8-K

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the
Securities Exchange Act of 1934

Date of Report (date of earliest event reported): September 2, 2003

Public Service Company of Colorado

(Exact name of registrant as specified in its charter)

Colorado

(State or other jurisdiction of incorporation)

001-3280	84-0296600
(Commission File Number)	(IRS Employer Identification No.)
1225 17th Street, Denver, Colorado	80202
(Address of principal executive offices)	(Zip Code)

Registrant’s telephone number, including area code: (303) 571-7511

(Former name or former address, if changed since last report)

TABLE OF CONTENTS

	Item 5. Other Events
	Item 7. Financial Statements and Exhibits.
SIGNATURES
EX-1.01 Underwriting Agreement
EX-4.01 Supplemental Indenture
EX-4.02 Supplemental Indenture No. 15

Item 5.      Other Events

On September 2, 2003, Public Service Company of Colorado, a Colorado corporation (the “Company”), entered into an Underwriting Agreement relating to $300,000,000 in aggregate principal amount of the Company’s 4.375% First Collateral Trust Bonds, Series No. 14 due 2008, and $275,000,000 in aggregate principal amount of the Company’s 5.50% First Collateral Trust Bonds, Series No. 15 due 2014.

Item 7.      Financial Statements and Exhibits.

	Exhibits
1.01	Underwriting Agreement dated September 2, 2003 between Public Service Company of Colorado and Banc One Capital Markets, Inc., McDonald Investments Inc. and UBS Securities LLC, as representatives of the Underwriters named therein, relating to $300,000,000 principal amount of 4.375% First Collateral Trust Bonds, Series No. 14 due 2008 and $275,000,000 principal amount of 5.50% First Collateral Trust Bonds, Series No. 15 due 2014.
4.01	Supplemental Indenture dated as of September 1, 2003 between Public Service Company of Colorado and U.S. Bank Trust National Association, as successor Trustee, creating an Issue of First Mortgage Bonds, Collateral Series N and an Issue of First Mortgage Bonds, Collateral Series O.
4.02	Supplemental Indenture No. 15 dated as of September 1, 2003 between Public Service Company of Colorado and U.S. Bank Trust National Association, as successor Trustee, creating $300,000,000 principal amount of 4.375% First Collateral Trust Bonds, Series No. 14 due 2008 and $275,000,000 principal amount of 5.50% First Collateral Trust bonds, Series No. 15 due 2014.

2

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, hereunto duly authorized.

Public Service Company of Colorado
By:	/s/ Benjamin G. S. Fowke III
Name: Benjamin G. S. Fowke III
Title: Vice President and Treasurer

Dated: September 2, 2003

3 EX-1.01 3 c79426exv1w01.txt EX-1.01 UNDERWRITING AGREEMENT PUBLIC SERVICE COMPANY OF COLORADO $575,000,000 $300,000,000 4.375% First Collateral Trust Bonds, Series No. 14, due 2008 $275,000,000 5.50% First Collateral Trust Bonds, Series No. 15, due 2014 UNDERWRITING AGREEMENT New York, New York September 2, 2003 Banc One Capital Markets, Inc. 1 Bank One Plaza Chicago, Illinois 60670 McDonald Investments Inc. 800 Superior Avenue Cleveland, Ohio 44114 UBS Securities LLC 677 Washington Boulevard Stamford, Connecticut 06901 As Representatives of the several Underwriters Ladies and Gentlemen: Public Service Company of Colorado, a corporation organized under the laws of the State of Colorado (the "Company"), proposes to issue and sell to the several parties named in Schedule I hereto (the "Underwriters"), for whom you (the "Representatives") are acting as representatives, $300,000,000 principal amount of the Company's 4.375% First Collateral Trust Bonds, Series No. 14, due 2008 and $275,000,000 principal amount of the Company's 5.50% First Collateral Trust Bonds, Series No. 15, due 2014 (collectively, the "Bonds"). The Bonds are to be issued under the Company's Indenture, dated as of October 1, 1993 (the "Original Indenture") to U.S. Bank Trust National Association, as successor trustee (the "Trustee"), as heretofore supplemented and as it will be further supplemented by a supplemental indenture creating the Bonds (said Original Indenture, as so supplemented and to be further supplemented, and said supplemental indenture being hereafter referred to as the "Indenture" and the "Supplemental Indenture", respectively). Certain terms used herein are defined in Section 16 hereof. 1. Representations and Warranties. The Company represents and warrants to, and agrees with, each Underwriter that: (a) (i) A registration statement on Form S-3 (File No. 333-104504) in respect of the Bonds and certain other securities has been prepared and filed with the Commission in accordance with the provisions of the Act; such registration statement and any post-effective amendment thereto have been declared effective by the Commission; such registration statement in the form in which it became effective and (including the exhibits thereto, but excluding the Statements of Eligibility in Form T-1) is hereinafter called the "Registration Statement"; and the prospectus relating to the Bonds, in the form in which it was included in the Registration Statement at the time it became effective, as supplemented by the prospectus supplement containing the terms of the Bonds and the terms of the offering thereof, in the form in which it is first filed with the Commission pursuant to Rule 424(b) under the Act, is hereinafter called the "Prospectus"; (ii) Pursuant to Rule 429 under the Act, the Prospectus will be used as a combined prospectus relating to the Registration Statement and to the registration statement filed by the Company with the Commission on June 29, 1999 (registration no. 333-81791) which became effective on July 6, 1999; unless the context otherwise requires, all references in this Agreement to the Registration Statement shall be deemed to include such prior registration statement; (iii) Any reference herein to the Registration Statement, any preliminary prospectus or the Prospectus shall be deemed to refer to and include the documents incorporated by reference therein pursuant to Item 12 of Form S-3 under the Act, as of the effective date for purposes of the Registration Statement or the date thereof for purposes of any preliminary prospectus or the Prospectus; any reference to any amendment to the Registration Statement shall be deemed to refer to and include any annual report of the Company filed pursuant to Section 13(a) or 15(d) of the Exchange Act after the effective date of the Registration Statement that is incorporated by reference in the Registration Statement; and any reference to any amendment or supplement to any preliminary prospectus or the Prospectus shall be deemed to refer to and include any documents filed after the date of such preliminary prospectus or Prospectus, under the Exchange Act, and incorporated by reference in such preliminary prospectus or Prospectus. (b) No stop order suspending the effectiveness of the Registration Statement has been issued and no proceeding for that purpose has been initiated or, to the best knowledge of the Company, threatened by the Commission and no order preventing or suspending the use of any preliminary prospectus or the Prospectus has been issued by the Commission; (c) The Registration Statement, when it became effective, conformed, and any further amendments thereto, when they become effective, will conform, in all material respects to the requirements of the Act and the Trust Indenture Act, and the Prospectus and any amendments or supplements thereto, when filed with the Commission, will conform in all material respects to the requirements of the Act and the Trust Indenture Act; (d) The Registration Statement, when it became effective, and any further amendments thereto when they become effective, did not and will not contain an untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein not misleading; and the Prospectus and any amendments and supplements thereto, when they are filed or transmitted for filing with the Commission and at the Closing Date, will not include an untrue statement of a material fact or omit to state a material fact necessary in order to make the statements made, in light of the 2 circumstances under which they were made, not misleading; provided, however, that the representations and warranties contained in this subsection (d) shall not apply to statements or omissions made in reliance upon and in conformity with information furnished in writing by an Underwriter through the Representatives expressly for use in the Registration Statement, the Prospectus or any amendment or supplement to either thereof; (e) The documents incorporated by reference in the Registration Statement or Prospectus, when they were filed with the Commission, and any further documents so filed and incorporated by reference, when they are filed with the Commission or become effective, as the case may be, complied with and will comply in all material respects with the requirements of the Exchange Act or the Act, as the case may be; (f) The Company is not, and after giving effect to the offering and sale of the Bonds and the application of the proceeds thereof as described in the Prospectus will not be, an "investment company" or an entity "controlled" by an "investment company" within the meaning of the Investment Company Act of 1940, as amended, without taking account of any exemption arising out of the number of holders of the Company's securities; (g) The Company is subject to and in full compliance with the reporting requirements of Section 13 or Section 15(d) of the Exchange Act; (h) The statements in the Prospectus under the headings "Supplemental Description of the First Collateral Trust Bonds," "Description of the First Collateral Trust Bonds," and "Description of the 1939 Mortgage" fairly summarize the matters therein described; (i) This Agreement has been duly authorized, executed and delivered by the Company; (j) The Indenture has been duly authorized and the Indenture (excluding the Supplemental Indenture) has been duly executed and delivered by the Company and is in due and proper form and (assuming the Indenture has been duly authorized, executed and delivered by the Trustee) when the Supplemental Indenture is duly executed and delivered the Indenture will constitute a legal, valid and binding mortgage of the Company, enforceable in accordance with its terms, except as enforcement thereof may be limited by laws and principles of equity affecting generally the enforcement of mortgagees' and other creditors' rights, including, without limitation, bankruptcy and insolvency laws and state laws which affect the enforcement of certain remedial provisions of the Indenture; provided, however, that such state laws will not render the remedies afforded by the Indenture inadequate for the practical realization of the benefit of the security provided thereby; (k) The issuance and sale by the Company of the Bonds pursuant to this Agreement have been duly authorized by all necessary corporate action; and, when issued, authenticated and delivered to the Underwriters pursuant to this Agreement against payment of the consideration therefor specified herein, the Bonds will be valid and binding obligations of the Company, enforceable in accordance with their terms, except as enforcement thereof may be limited by laws or principles of equity affecting generally the enforcement of mortgagees' and other creditors' rights, including, without limitation, bankruptcy and 3 insolvency laws and state laws which affect the enforcement of certain remedial provisions of the Indenture, and will be entitled to the benefits of the Indenture; (l) The PSCO 1939 Mortgage (as defined in the Indenture) has been duly authorized and the PSCO 1939 Mortgage (excluding the Mortgage Supplement) has been duly executed and delivered by the Company and is in due and proper form and (assuming the PSCO 1939 Mortgage has been duly authorized, executed and delivered by the trustee thereunder) when the Mortgage Supplement is duly executed and delivered the PSCO 1939 Mortgage will constitute a legal, valid and binding mortgage of the Company, enforceable in accordance with its terms, except as enforcement thereof may be limited by laws and principles of equity affecting generally the enforcement of mortgagees' and other creditors' rights, including, without limitation, bankruptcy and insolvency laws and state laws which affect the enforcement of certain remedial provisions of the PSCO 1939 Mortgage; provided, however, that such state laws will not render the remedies afforded by the PSCO 1939 Mortgage inadequate for the practical realization of the benefit of the security provided thereby; (m) The issuance and delivery by the Company of the Class A Bonds (as defined in the Indenture) to be made the basis of the authentication and delivery of the Bonds (the "Class A Bonds") have been duly authorized by all necessary corporate action; and when (i) the Class A Bonds have been issued, authenticated and delivered to the Trustee pursuant to the Indenture and (ii) the Bonds have been issued, authenticated and delivered to the Underwriters pursuant to this Agreement against payment of the consideration therefor specified herein, the Class A Bonds will be valid and binding obligations of the Company, enforceable in accordance with their terms, except as enforcement thereof may be limited by laws or principles of equity affecting generally the enforcement of mortgagees' and other creditors' rights, including, without limitation, bankruptcy and insolvency laws and state laws which affect the enforcement of certain remedial provisions of the PSCO 1939 Mortgage, and will be entitled to the benefits of the PSCO 1939 Mortgage; (n) The issuance and sale of the Bonds, and the issuance and delivery of the Class A Bonds, have been duly authorized and approved by an order of The Public Utilities Commission of the State of Colorado and such order is final and in full force and effect on the date hereof, the time for appeal therefrom or review thereof or intervention with respect thereto having expired; no further approval, authorization, consent or other order of any public board or body is legally required in connection with the transactions contemplated by this Agreement, the Indenture or the PSCO 1939 Mortgage, except for the registration under the Act of the Bonds and as may be required under the blue sky laws of any jurisdiction in connection with the purchase and distribution of the Bonds by the Underwriters in the manner contemplated herein and in the Prospectus; (o) Neither the execution and delivery of this Agreement or the Supplemental Indenture, the issue and sale of the Bonds, nor the consummation of any other of the transactions herein or therein contemplated, nor the fulfillment of the terms hereof or thereof will conflict with, result in a breach or violation or imposition of any lien, charge or encumbrance upon any property or assets of the Company or any of its subsidiaries, other than the liens and security interests created by the Indenture and the PSCo 1939 Mortgage, pursuant to, (i) the charter or by-laws of the Company or any of its subsidiaries; (ii) the terms of any indenture, contract, lease, mortgage, deed of trust, note agreement, loan agreement or 4 other agreement, obligation, condition, covenant or instrument to which the Company or any of its subsidiaries is a party or bound or to which its or their property is subject; or (iii) any statute, law, rule, regulation, judgment, order or decree applicable to the Company or any of its subsidiaries of any court, regulatory body, administrative agency, governmental body, arbitrator or other authority having jurisdiction over the Company or any of its subsidiaries or any of its or their properties except, in the case of clause (ii), any such conflict, breach or violation which would not, individually or in the aggregate, have a material adverse change in the condition (financial or otherwise), prospects, earnings, business or properties of the Company and its subsidiaries taken as a whole, whether or not arising from transactions in the ordinary course of business; (p) The Company has good title to the properties specifically or generally described or referred to in the Indenture and in the PSCO 1939 Mortgage as subject to the respective liens thereof (except such property as may have been sold, exchanged or otherwise disposed of) subject only to (a) in the case of all such properties, the lien of the PSCO 1939 Mortgage and "permitted encumbrances" (as defined in the PSCO 1939 Mortgage) and (b) in the case of such properties which are used or to be used in or in connection with the Electric Utility Business (as defined in the Indenture) (whether or not such is the sole use of such property) the lien of the Indenture and Permitted Liens (as defined in the Indenture); (q) The Indenture constitutes a mortgage lien on the properties specifically or generally described or referred to therein as subject to the lien thereof (except such properties as may have been sold, exchanged or otherwise disposed of or released from the lien thereof in accordance with the terms thereof), subject to no liens prior to the lien of the Indenture other than Permitted Liens and the lien of the PSCO 1939 Mortgage; and the Indenture by its terms effectively subjects to the lien thereof all property (except property of the kinds specifically excepted from the lien of the Indenture) acquired by the Company after the date of execution and delivery of the Indenture and used or to be used in or in connection with the Electric Utility Business, subject to Permitted Liens, the lien of the PSCO 1939 Mortgage, any lien thereon existing at the time of such acquisition and to any liens for unpaid portions of the purchase money placed thereon at the time of such acquisition, and also subject to the provisions of Article Thirteen of the Indenture and to certain possible claims of a trustee in bankruptcy and possible claims and taxes of the federal government; (r) The PSCO 1939 Mortgage constitutes a first mortgage lien on the properties specifically or generally described or referred to therein as subject to the lien thereof, including the shares of stock pledged thereunder (except such property as may have been sold, exchanged or otherwise disposed of or released from the lien thereof in accordance with the terms thereof), subject to no liens prior to the lien of the PSCO 1939 Mortgage other than "permitted encumbrances"; and the PSCO 1939 Mortgage by its terms effectively subjects to the lien thereof all property (except property of the kinds specifically excepted from the lien of the PSCO 1939 Mortgage) acquired by the Company after the date of the execution and delivery of the PSCO 1939 Mortgage, subject to "permitted encumbrances", to any lien thereon existing at the time of such acquisition and to any liens for unpaid portions of the purchase money placed thereon at the time of such acquisition, and also subject to the provisions of Article XI of the PSCO 1939 Mortgage and to certain possible claims of a trustee in bankruptcy and possible claims and taxes of the federal government; 5 (s) The consolidated historical financial statements and schedules of the Company and its consolidated subsidiaries included or incorporated by reference in the Registration Statement and Prospectus present fairly in all material respects the financial condition, results of operations, cash flows and changes in financial position of the Company as of the dates and for the periods indicated, comply as to form with the applicable accounting requirements of the Act and the Exchange Act and have been prepared in conformity with GAAP throughout the periods involved (except as otherwise noted therein); the selected financial data set forth under the caption "Selected Consolidated Financial Data" in the Prospectus fairly present, on the basis stated in the Prospectus, the information included therein. Except as disclosed in or incorporated by reference in the Registration Statement and Prospectus, neither the Company nor any of its subsidiaries has any contingent obligations which are material to the Company and its consolidated subsidiaries taken as a whole; (t) Deloitte & Touche LLP, which audited the financial statements incorporated by reference in the Registration Statement and Prospectus, (A) are independent public accountants as required by the Act and the rules and regulations of the Commission thereunder and (B) do not provide to the Company or its subsidiaries any non-audit services which are prohibited by Section 10A(g) or (h) of the Exchange Act; (u) The statistical and market-related data and forward-looking statements (within the meaning of Section 27A of the Act and Section 21E of the Exchange Act) included or incorporated by reference in the Prospectus are based on or derived from sources that the Company believes to be reliable and accurate in all material respects and represent good faith estimates that are made on the basis of data derived from such sources; (v) Except as may otherwise be reflected in or contemplated by the Registration Statement and Prospectus, since the respective dates as of which information is given in the Registration Statement and Prospectus (i) there has been no material adverse change in the condition (financial or otherwise), prospects, earnings, business or properties of the Company and its subsidiaries taken as a whole, whether or not arising from transactions in the ordinary course of business and (ii) neither the Company nor any of its subsidiaries has entered into any transactions which are material to the Company and its subsidiaries taken as a whole, other than in the ordinary course of business; and, except as so reflected or contemplated, neither the Company nor any of its subsidiaries has any contingent obligations which are material to the Company and its subsidiaries taken as a whole; (w) Each of the Company and its subsidiaries has been duly incorporated and is validly existing as a corporation in good standing under the laws of the jurisdiction in which it is chartered or organized with full corporate power and authority to own or lease, as the case may be, and to operate its properties and conduct its business as described in the Registration Statement and Prospectus, and is duly qualified to do business as a foreign corporation and is in good standing under the laws of each jurisdiction in which such qualification is required, whether by reason of the ownership or leasing of property or the conduct of business, except where the failure to be so qualified would not have a material adverse change in the condition (financial or otherwise), prospects, earnings, business or properties of the Company and its subsidiaries taken as a whole, whether or not arising from transactions in the ordinary course of business; 6 (x) All the outstanding shares of capital stock of each subsidiary have been duly and validly authorized and issued and are fully paid and nonassessable, and, except as otherwise set forth in the Registration Statement and Prospectus, all outstanding shares of capital stock of the subsidiaries are owned by the Company either directly or through wholly-owned subsidiaries free and clear of any perfected security interest or any other security interests, claims, liens or encumbrances; (y) The Company has no subsidiaries which would be deemed significant subsidiaries under Regulation S-X; (z) Neither the Company nor any of its subsidiaries is in violation or default of (i) any provision of its charter or bylaws; (ii) the terms of any indenture, contract, lease, mortgage, deed of trust, note agreement, loan agreement or other agreement, obligation, condition, covenant or instrument to which it is a party or bound or to which its property is subject; or (iii) any statute, law, rule, regulation, judgment, order or decree applicable to the Company or any of its subsidiaries of any court, regulatory body, administrative agency, governmental body, arbitrator or other authority having jurisdiction over the Company or such subsidiary or any of its properties, as applicable except, in the case of clause (ii) or (iii), any such conflict, breach or violation which would not, individually or in the aggregate, have a material adverse change in the condition (financial or otherwise), prospects, earnings, business or properties of the Company and its subsidiaries taken as a whole, whether or not arising from transactions in the ordinary course of business; (aa) The Company, either directly or through its parent, has filed all foreign, federal, state and local tax returns that are required to be filed or has requested extensions thereof (except in any case in which the failure so to file would not have a material adverse effect on the condition (financial or otherwise), prospects, earnings, business or properties of the Company and its subsidiaries, taken as a whole, whether or not arising from transactions in the ordinary course of business, except as set forth in or contemplated in the Registration Statement and Prospectus and has paid, either directly or through its parent, all taxes required to be paid by it and any other assessment, fine or penalty levied against it, to the extent it has notice that any of the foregoing is due and payable, except for any such assessment, fine or penalty that is currently being contested in good faith or as would not have a material adverse effect on the condition (financial or otherwise), prospects, earnings, business or properties of the Company and its subsidiaries, taken as a whole, whether or not arising from transactions in the ordinary course of business, except as set forth in or contemplated in the Registration Statement and Prospectus; (bb) The Company and each of its subsidiaries are insured by insurers of recognized financial responsibility against such losses and risks and in such amounts as are prudent and customary in the businesses in which they are engaged; all material policies of insurance and fidelity or surety bonds insuring the Company or any of its subsidiaries or their respective businesses, assets, employees, officers and directors are in full force and effect; the Company and its subsidiaries are in compliance with the terms of such material policies and instruments in all material respects; and there are no material claims by the Company or any of its subsidiaries under any such policy or instrument as to which any insurance company is denying liability or defending under a reservation of rights clause; neither the Company nor any such subsidiary has been refused any material insurance coverage sought or applied for; 7 (cc) No subsidiary of the Company is currently prohibited, directly or indirectly, from paying any dividends to the Company, from making any other distribution on such subsidiary's capital stock, from repaying to the Company any loans or advances to such subsidiary from the Company or from transferring any of such subsidiary's property or assets to the Company or any other subsidiary of the Company, except as described in or contemplated by the Registration Statement and Prospectus; (dd) Neither the Company, nor any of its subsidiaries, nor any director, officer, agent, employee or other person or entity acting on behalf of the Company or any of its subsidiaries has, in the course of its actions for, or on behalf of, the Company, used any corporate funds for any unlawful contribution, gift, entertainment or other unlawful expenses relating to political activity; made any direct or indirect unlawful payment to any foreign or domestic government official or employee from corporate funds; violated or is in violation of any provision of the U.S. Foreign Corrupt Practices Act of 1977, as amended; or made any unlawful bribe, rebate, payoff, influence payment, kickback or other unlawful payment to any foreign or domestic government official or employee; (ee) (A) The Company has established and maintains disclosure controls and procedures (as such term is defined in Rule 13a-15(e) under the Exchange Act, "Disclosure Controls"); and such Disclosure Controls are (i) designed to ensure that material information relating to the Company, including its consolidated subsidiaries, is properly recorded, processed, summarized and communicated to the Company's senior management, including its principal executive officer and its principal financial officer, by others within those entities as appropriate to allow timely decisions regarding required disclosure, (ii) evaluated by the Company's senior management on a quarterly basis and (iii) to the best knowledge of the Company, effective in all material respects to perform the functions for which they were established; (B) The Company has designed and maintains internal control over financial reporting (as such term is defined in Rule 13a-15(f) under the Exchange Act, "Reporting Controls"); and the Reporting Controls are (i) designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with GAAP and include, without limitation, those processes specifically referred to in Rule 13a-15(f) and (ii) to the best knowledge of the Company, effective to perform the functions for which they are maintained; (C) The Company has devised and maintains in effect a system of internal accounting controls ("Accounting Controls"); and such Accounting Controls are sufficient to provide reasonable assurances that (i) transactions involving the Company and its subsidiaries are executed in accordance with management's general or specific authorization; (ii) transactions are recorded as necessary (I) to permit preparation of financial statements in conformity with generally accepted accounting principles and (II) to maintain accountability for assets; (iii) access to assets is permitted only in accordance with management's general or specific authorization; and (iv) the recorded accountability for assets is compared with the existing assets at reasonable intervals and appropriate action is taken with respect to any differences; (D) Based on the most recent evaluation of the Company's internal controls referred to above, all significant deficiencies in the design or operation of such 8 internal controls which could adversely affect the Company's ability to record, process, summarize and report financial data required to be disclosed by the Company in its Exchange Act reports within the time periods specified in the Exchange Act, any material weaknesses in such internal controls and any fraud, whether or not material, that involves management or other employees who have a significant role in such internal controls have been identified and reported to the Company's auditors and the audit committee of the board of directors; and all such deficiencies and weaknesses, if any, have been rectified; (ff) Except as set forth in, or incorporated by reference in, the Registration Statement and Prospectus, the Company and its subsidiaries (i) are in compliance with any and all applicable federal, state and local laws and regulations relating to the protection of human health and safety, the environment or hazardous or toxic substances or wastes, pollutants or contaminants ("Environmental Laws"), (ii) have received all permits, licenses or other approvals required of them under applicable Environmental Laws to conduct their respective businesses, (iii) are in compliance with all terms and conditions of any such permits, licenses or approvals, and (iv) have not received notice of any actual or potential liability for the investigation or remediation of any disposal or release of hazardous or toxic substances or wastes, pollutants or contaminants, except where such non-compliance with Environmental Laws, failure to receive required permits, licenses or other approvals, or any such liability would not, individually or in the aggregate, have a material adverse change in the condition (financial or otherwise), prospects, earnings, business or properties of the Company and its subsidiaries, taken as a whole, whether or not arising from transactions in the ordinary course of business; (gg) With respect to each employee benefit plan (as defined in Section 3(3) of the Employee Retirement Income Security Act of 1974, as amended ("ERISA")) which the Company or any other organization that together with the Company is treated as a single employer under Sections 414(b), (c), (m) or (o) of the Internal Revenue Code of 1986, as amended (the "Code") (an "ERISA Affiliate"), has at any time sponsored, maintained, contributed to or been obligated to contribute to (a "Plan"): (i) the Company and each ERISA Affiliate have administered and operated each Plan sponsored or maintained by the Company or an ERISA Affiliate in compliance with ERISA, the Code and other applicable laws except for such instances of noncompliance as have not resulted in and could not reasonably be expected to result in a material liability to the Company or ERISA Affiliate; (ii) each Plan sponsored or maintained by the Company or an ERISA Affiliate intended to qualify under Section 401(a) of the Code so qualifies and to the Company's knowledge nothing has occurred, whether by action or failure to act, which could reasonably be expected to cause the loss of such qualification of any such Plan; (iii) neither the Company nor any ERISA Affiliate has incurred, and to the Company's knowledge no event, transaction or condition has occurred or exists under which the Company or any ERISA Affiliate could reasonably expect to incur, any material liability or the imposition of any lien on any of the rights, properties or assets of the Company or any ERISA Affiliate pursuant to Title I or Title IV of ERISA (other than routine claims for benefits) or applicable penalty or excise provisions of the Code; (iv) there has been no reportable event (within the meaning of Section 4043 of ERISA) with respect to any Plan subject to Title IV of ERISA that is sponsored or maintained by the Company or an ERISA Affiliate for which the 30-day reporting requirement has not been waived which could reasonably be expected to result in a material liability under Title IV of ERISA to the Company or an ERISA Affiliate; (v) no accumulated funding deficiency (within the meaning of Section 302 of ERISA and Section 9 412 of the Code), whether or not waived, exists with respect to any Plan subject to Title IV of ERISA that is sponsored or maintained by the Company; and (vi) neither the Company nor any ERISA Affiliate has incurred, and to the Company's knowledge no event, transaction or condition has occurred or exists under which the Company or any ERISA Affiliate could reasonably expect to incur, any material liability with respect to termination of, or withdrawal from, any Plan subject to Title IV of ERISA; (hh) The franchises held by the Company and its subsidiaries, together with the applicable Certificates of Convenience and Necessity issued by The Public Utilities Commission of the State of Colorado, give the Company and such subsidiaries all necessary authority for the maintenance and operation of their respective properties and business as now conducted, and are free from burdensome restrictions or conditions of an unusual character. Any certificate signed by any officer of the Company and delivered to the Representatives or counsel for the Representatives in connection with the offering of the Bonds shall be deemed a representation and warranty by the Company, as to matters covered thereby, to each Underwriter. 2. Purchase and Sale. Subject to the terms and conditions and in reliance upon the representations and warranties herein set forth, the Company agrees to sell to each Underwriter, severally and not jointly, and each Underwriter agrees, severally and not jointly, to purchase from the Company, (a) at a purchase price of 99.280% of the principal amount thereof, plus accrued interest, if any, from September 9, 2003 to the Closing Date, the principal amount of 4.375% First Collateral Trust Bonds, Series No. 14 due 2008 set forth opposite such Underwriter's name in Schedule I hereto and (b) at a purchase price of 98.611% of the principal amount thereof, plus accrued interest, if any, from September 9, 2003 to the Closing Date, the principal amount of 5.50% First Collateral Trust Bonds, Series No. 15, due 2014 set forth opposite such Underwriters name in Schedule 1 hereto. It is understood that the several underwriters propose to offer the Bonds for sale to the public as set forth in the Prospectus. 3. Delivery and Payment. Delivery of and payment for the Bonds shall be made at 10:00 A.M., New York City time, on September 9, 2003, or at such time on such later date as the Representatives shall designate, which date and time may be postponed by agreement between the Representatives and the Company or as provided in Section 8 hereof (such date and time of delivery and payment for the Bonds being herein called the "Closing Date"). Delivery of the Bonds shall be made to the Representatives for the respective accounts of the several Underwriters against payment by the several Underwriters through the Representatives of the purchase price thereof to or upon the order of the Company by wire transfer payable in same-day funds to the account specified by the Company. Delivery of the Bonds shall be made through the facilities of The Depository Trust Company. 4. Agreements. The Company agrees with each Underwriter: (a) To prepare the Prospectus in a form approved by the Representatives and to file such Prospectus pursuant to Rule 424(b) under the Act not later than the Commission's close of business on the second business day following the execution and delivery of this Agreement; to make no further amendment or any supplement to the Registration Statement or Prospectus prior to the Closing Date which shall be reasonably disapproved by the 10 Representatives promptly after reasonable notice thereof; during the period for which a prospectus is required to be delivered under the Act in connection with the offering and sale of the Bonds, to advise the Representatives, promptly after it receives notice thereof, of the time when any amendment to the Registration Statement has been filed or becomes effective or any supplement to the Prospectus or any amended Prospectus has been filed and to furnish the Representatives with copies thereof; to file promptly all reports and any definitive proxy or information statements required to be filed by the Company with the Commission pursuant to Section 13(a), 13(c), 14 or 15(d) of the Exchange Act subsequent to the date of the Prospectus and for so long as the delivery of a prospectus is required under the Act in connection with the offering or sale of the Bonds; to advise the Representatives, promptly after it receives notice thereof, of the issuance by the Commission of any stop order or of any order preventing or suspending the use of any prospectus, of the suspension of the qualification of the Bonds for offering or sale in any jurisdiction, of the initiation or threatening of any proceeding for any such purpose, or of any request by the Commission for the amending or supplementing of the Registration Statement or the Prospectus or for additional information; to use its best efforts to prevent the issuance of any stop order or of any order preventing or suspending the use of any prospectus or suspending any such qualification, and, in the event of the issuance of any such order, promptly to use its best efforts to obtain the withdrawal of such order; (b) Promptly from time to time to take such action as the Representatives may reasonably request to qualify the Bonds for offering and sale under the securities laws of such jurisdictions as the Representatives may request and to comply with such laws so as to permit the continuance of sales and dealings therein in such jurisdictions for as long as may be necessary to complete the distribution of the Bonds, provided that in connection therewith the Company shall not be required to qualify as a foreign corporation or to file a general consent to service of process in any jurisdiction; (c) Prior to 10:00 a.m., New York City time, on the third Business Day next succeeding the date of this Agreement and from time to time, to furnish the Underwriters with written and electronic copies of the Prospectus in such quantities as the Representatives may from time to time reasonably request, and, if the delivery of a prospectus is required under the Act at any time in connection with the offering or sale of the Bonds and if at such time any event shall have occurred as a result of which the Prospectus as then amended or supplemented would include an untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made when such Prospectus is delivered, not misleading, or, if for any other reason it shall be necessary during such period to amend or supplement the Prospectus or to file under the Exchange Act any document incorporated by reference in the Prospectus in order to comply with the Act, the Exchange Act or the Trust Indenture Act, to notify the Representatives and upon their reasonable request to file such document and to prepare and furnish without charge to each Underwriter and to any dealer in securities as many written and electronic copies as the Representatives may from time to time reasonably request of an amended Prospectus or a supplement to the Prospectus which will correct such statement or omission or effect such compliance; (d) To make generally available to its securityholders and to the Representatives as soon as practicable, but in any event not later than eighteen months after the effective date of the Registration Statement (as defined in Rule 158(c) under the Act), an earnings 11 statement of the Company and its subsidiaries (which need not be audited) covering a period of at least 12 months beginning after the later of (i) the effective date of the most recent post-effective amendment to the Registration Statement to become effective prior to the date of this Agreement and (ii) the date of the Company's most recent Annual Report on Form 10-K filed with the Commission prior to the date of this Agreement, which will satisfy the provisions of Section 11(a) of the Act and the rules and regulations thereunder including Rule 158; (e) For a period of 14 days following the Execution Time, without the prior written consent of the Representatives, not to offer, sell or contract to sell, or otherwise dispose of (or enter into any transaction which is designed to, or might reasonably be expected to, result in the disposition (whether by actual disposition or effective economic disposition due to cash settlement or otherwise) by the Company, directly or indirectly, or announce the offering of) any long-term debt securities issued or guaranteed by the Company, other than the Bonds and the bonds contemplated by any Shelf Registration Statement or Exchange Offer Registration Statement (as such terms are defined in the Registration Rights Agreement dated March 14, 2003, between the Company and Banc One Capital Markets Inc. and UBS Securities LLC, as representatives of the Initial Purchasers (as identified therein)); (f) To use the net proceeds received by it from the sale of the Bonds pursuant to this Agreement in the manner specified in the Prospectus under the caption "Use of Proceeds"; (g) To pay the costs and expenses relating to the following matters: (i) the preparation of the Supplemental Indenture the issuance of the Bonds and the fees of the Trustee; (ii) the preparation, printing and filing of the Registration Statement (including all exhibits thereto), the preliminary prospectus, the Prospectus (including all documents incorporated by reference therein) and any amendments thereof or supplements thereto and the printing and furnishing of such copies of each thereof to the Underwriters and to dealers (including postage, air freight charges and charges for counting and packaging), as may be reasonably requested for use in connection with the offering and sale of the Bonds; (iii) the preparation, printing, authentication, issuance and delivery of certificates for the Bonds, including any stamp or transfer taxes in connection with the original issuance and sale of the Bonds; (iv) the printing (or reproduction) and delivery of this Agreement, any blue sky memorandum and all other agreements or documents printed (or reproduced) and delivered in connection with the offering of the Bonds; (v) any registration or qualification of the Bonds for offer and sale under the securities or blue sky laws of the several states (including filing fees and the reasonable fees and expenses of counsel for the Underwriters relating to such registration and qualification); (vi) the transportation and other expenses incurred by or on behalf of Company representatives in connection with presentations to prospective purchasers of the Bonds; (vii) the fees and expenses of the Company's accountants and counsel (including local and special counsel); (viii) the fees and expenses of any rating agencies rating the Bonds and (ix) all other costs and expenses incident to the performance by the Company of its obligations hereunder. 5. Conditions to the Obligations of the Underwriters. The obligations of the Underwriters to purchase the Bonds shall be subject to the accuracy of the representations and warranties on the part of the Company contained herein at the Execution Time and the Closing Date, 12 to the accuracy of the statements of the Company made in any certificates pursuant to the provisions hereof, to the performance by the Company of its obligations hereunder and to the following additional conditions: (a) (i) The Prospectus shall have been filed with the Commission pursuant to Rule 424(b) within the applicable time period prescribed for such filing by the rules and regulations under the Act and in accordance with Section 4(a) hereof; (ii) no stop order suspending the effectiveness of the Registration Statement or any part thereof shall have been issued and no proceeding for that purpose shall have been initiated or threatened by the Commission; and (iii) all requests for additional information on the part of the Commission shall have been complied with to the Representatives' reasonable satisfaction; (b) At the Closing Date, the Representatives shall have received opinions, dated the Closing Date, of Ann E. Hopfenbeck, Assistant General Counsel, Xcel Energy Services, Attorney for the Company, Jones Day and LeBoeuf, Lamb, Greene and MacRae, LLP, counsel for the Company, substantially to the effect set forth in Exhibit A hereto and other related matters as the Representatives may reasonably require, with reproduced or conformed copies thereof for each of the Purchasers, and the Company shall have furnished to such counsel such documents as they request for the purpose of enabling them to pass upon such matters; (c) At the Closing Date, the Representatives shall have received from Dewey Ballantine LLP, counsel for the Underwriters, such opinion or opinions, dated the Closing Date and addressed to the Representatives, with respect to the issuance and sale of the Bonds, the Indenture, the Registration Statement, the Prospectus and other related matters as the Representatives may reasonably require, and the Company shall have furnished to such counsel such documents as they request for the purpose of enabling them to pass upon such matters; (d) The Company shall have furnished to the Representatives a certificate of the Company, signed by the President or any Vice President and the Treasurer of the Company, dated the Closing Date, to the effect that the signer of such certificate has carefully examined the Registration Statement and all amendments thereto, the Prospectus and all amendments or supplements thereto and this Agreement and that: (i) the representations and warranties of the Company in this Agreement are true and correct in all material respects on and as of the Closing Date with the same effect as if made on the Closing Date, and the Company has complied with all the agreements and satisfied all the conditions on its part to be performed or satisfied hereunder at or prior to the Closing Date; and (ii) since the date of the most recent financial statements included or incorporated by reference in the Prospectus, there has been no material adverse change in the condition (financial or otherwise), prospects, earnings, business or properties of the Company and its subsidiaries taken as a whole, whether or not arising from transactions in the ordinary course of business, except as set forth in or contemplated by the Prospectus. (e) At the Execution Time and at the Closing Date, the Company shall have requested and caused Deloitte & Touche LLP to furnish to the Representatives letters, dated 13 respectively as of the Execution Time and as of the Closing Date, substantially to the effect set forth in Exhibit B hereto; (f) Subsequent to the Execution Time or, if earlier, the dates as of which information is given in the Prospectus, there shall not have been (i) any change or decrease specified in the letter or letters referred to in paragraph (e) of this Section 5; or (ii) any change, or any development involving a prospective change, in or affecting the financial condition, business or properties of the Company and its subsidiaries, taken as a whole, whether or not arising from transactions in the ordinary course of business, except as set forth in or contemplated in the Prospectus the effect of which, in any case referred to in clause (i) or (ii) above, is, in the sole judgment of the Representatives, so material and adverse as to make it impractical or inadvisable to market the Bonds as contemplated by the Prospectus. (g) Subsequent to the Execution Time, there shall not have been any decrease in the rating or outlook of any of the Company's debt securities by any "nationally recognized statistical rating organization" (as defined for purposes of Rule 436(g) under the Act) or any public announcement of any intended or potential decrease in any such rating or outlook or of a possible change in any such rating or outlook that does not indicate the direction of the possible change; (h) The Company shall have complied with the provisions of Section 4(c) hereof with respect to the furnishing of prospectuses. (i) Prior to the Closing Date, the Company shall have furnished to the Representatives such further information, certificates and documents as the Representatives may reasonably request. If any of the conditions specified in this Section 5 shall not have been fulfilled in all material respects when and as provided in this Agreement, or if any of the opinions and certificates mentioned above or elsewhere in this Agreement shall not be in all material respects reasonably satisfactory in form and substance to the Representatives and counsel for the Underwriters, this Agreement and all obligations of the Underwriters hereunder may be cancelled at, or at any time prior to, the Closing Date by the Representatives. Notice of such cancellation shall be given to the Company in writing or by telephone or facsimile confirmed in writing. The documents required to be delivered by this Section 5 will be delivered at the office of counsel for the Company, at Jones Day, on the Closing Date. 6. Reimbursement of Expenses. If the sale of the Bonds provided for herein is not consummated because any condition to the obligations of the Underwriters set forth in Section 5 hereof is not satisfied, because of any termination pursuant to clause (i) of Section 9 hereof or because of any refusal, inability or failure on the part of the Company to perform any agreement herein or comply with any provision hereof, other than by reason of a default by any of the Underwriters, the Company will reimburse the Underwriters on demand for all out-of-pocket expenses (including reasonable fees and disbursements of counsel) that shall have been incurred by them in connection with the proposed purchase and sale of the Bonds. 7. Indemnification and Contribution. (a) The Company agrees to indemnify and hold harmless each Underwriter, the directors, members, officers, employees and agents of each 14 Underwriter and each person who controls any Underwriter within the meaning of either the Act or the Exchange Act against any and all losses, claims, damages or liabilities, joint or several, to which they or any of them may become subject under the Act, the Exchange Act or other Federal or state statutory law or regulation, at common law or otherwise, insofar as such losses, claims, damages or liabilities (or actions in respect thereof) arise out of or are based upon any untrue statement or alleged untrue statement of a material fact contained in the Registration Statement or any amendment thereto, in any preliminary prospectus or preliminary prospectus supplement or in the Prospectus or any amendment or supplement thereto, or arise out of or are based upon the omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading, and agrees to reimburse each such indemnified party, as incurred, for any legal or other expenses reasonably incurred by them in connection with investigating or defending any such loss, claim, damage, liability or action; provided, however, that the Company will not be liable in any such case to the extent that any such loss, claim, damage or liability arises out of or is based upon any such untrue statement or alleged untrue statement or omission or alleged omission made in the Registration Statement or any amendment thereto, in any preliminary prospectus or preliminary prospectus supplement or in the Prospectus or any amendment or supplement thereto, in reliance upon and in conformity with written information furnished to the Company by or on behalf of any Underwriter through the Representatives specifically for inclusion therein; provided, further, that with respect to any such untrue statement in or omission from any preliminary prospectus, the indemnity contained in this paragraph (a) shall not inure to the benefit of any Underwriter or its directors, members, officers, employees and agents, and each person, if any, who controls such Underwriter to the extent that the sale to the person asserting any such loss, claim, damage or liability was an initial sale by such Underwriter and any such loss, claim, damage or liability of or with respect to such Underwriter results from the fact that both (i) to the extent required by applicable law, a copy of the Prospectus was not sent or given to such person at or prior to the written confirmation of the sale of the Bonds to such person and (ii) the untrue statement in or omission from such preliminary prospectus was corrected in the Prospectus unless, in either case, such failure to deliver the Prospectus was a result of non-compliance by the Company with the provisions of Section 4(c) hereof. This indemnity agreement will be in addition to any liability which the Company may otherwise have; (b) Each Underwriter severally and not jointly agrees to indemnify and hold harmless the Company, and each of its directors, officers, employees and agents, and each person who controls the Company within the meaning of either the Act or the Exchange Act, to the same extent as the foregoing indemnity from the Company to each Underwriter, but only with reference to written information relating to such Underwriter furnished to the Company by or on behalf of such Underwriter through the Representatives specifically for inclusion in the Prospectus or any amendment or supplement thereto. This indemnity agreement will be in addition to any liability which such Underwriter may otherwise have. The Company acknowledges that the statements set forth in (i) the last sentence of the cover page of the Prospectus regarding the delivery of the Bonds, (ii) the third paragraph of text under the caption "Underwriting" in the Prospectus, (iii) the first, second and third sentences of the sixth paragraph of text under the caption "Underwriting" in the Prospectus and (iv) the seventh and eighth paragraphs of text under the caption "Underwriting" in the Prospectus constitute the only information furnished in writing by or on behalf of the Underwriters for inclusion in the Prospectus (or any amendment or supplement thereto); (c) Promptly after receipt by an indemnified party under this Section 7 of notice of the commencement of any action, such indemnified party will, if a claim in respect thereof is to be made against the indemnifying party under this Section 7, notify the indemnifying party in writing of 15 the commencement thereof; but the failure so to notify the indemnifying party (i) will not relieve it from liability under paragraph (a) or (b) above unless and to the extent it did not otherwise learn of such action and such failure results in the forfeiture by the indemnifying party of substantial rights and defenses; and (ii) will not, in any event, relieve the indemnifying party from any obligations to any indemnified party other than the indemnification obligation provided in paragraph (a) or (b) above. The indemnifying party shall be entitled to appoint counsel of the indemnifying party's choice at the indemnifying party's expense to represent the indemnified party in any action for which indemnification is sought (in which case the indemnifying party shall not thereafter be responsible for the fees and expenses of any separate counsel retained by the indemnified party or parties except as set forth below); provided, however, that such counsel shall be reasonably satisfactory to the indemnified party. Notwithstanding the indemnifying party's election to appoint counsel to represent the indemnified party in an action, the indemnified party shall have the right to employ separate counsel (including local counsel), and the indemnifying party shall bear the reasonable fees, costs and expenses of such separate counsel if (i) the use of counsel chosen by the indemnifying party to represent the indemnified party would present such counsel with a conflict of interest; (ii) the actual or potential defendants in, or targets of, any such action include both the indemnified party and the indemnifying party and the indemnified party shall have reasonably concluded that there may be legal defenses available to it and/or other indemnified parties which are different from or additional to those available to the indemnifying party; (iii) the indemnifying party shall not have employed counsel satisfactory to the indemnified party to represent the indemnified party within a reasonable time after notice of the institution of such action; or (iv) the indemnifying party shall authorize the indemnified party to employ separate counsel at the expense of the indemnifying party, it being understood, however, that in each case the indemnifying party shall not, in connection with any one such action or separate but substantially similar or related actions in the same jurisdiction arising out of the same general allegations or circumstances, be liable for the reasonable fees and expenses of more than one separate firm of attorneys (in addition to any local counsel) at any time for all such indemnified parties, which firm shall be designated by the Representatives if the indemnified parties consist of the Underwriters or their directors, members, officers, employees or agents. An indemnifying party will not, without the prior written consent of the indemnified parties, settle or compromise or consent to the entry of any judgment with respect to any pending or threatened claim, action, suit or proceeding in respect of which indemnification or contribution may be sought hereunder (whether or not the indemnified parties are actual or potential parties to such claim or action) unless such settlement, compromise or consent includes an unconditional release of each indemnified party from all liability arising out of such claim, action, suit or proceeding; (d) In the event that the indemnity provided in paragraph (a) or (b) of this Section 7 is for any reason held to be unenforceable by an indemnified party although applicable in accordance with its terms, the Company and the Underwriters agree to contribute to the aggregate losses, claims, damages and liabilities (including legal or other expenses reasonably incurred in connection with investigating or defending same) (collectively, "Losses") to which the Company and one or more of the Underwriters may be subject in such proportion as is appropriate to reflect the relative benefits received by the Company on the one hand and by the Underwriters on the other from the offering of the Bonds; provided, however, that in no case shall any Underwriter (except as may be provided in any agreement among the Underwriters relating to the offering of the Bonds) be responsible for any amount in excess of the purchase discount or commission applicable to the Bonds purchased by such Underwriter hereunder; provided, further, that each Underwriter's obligation to contribute to Losses hereunder shall be several and not joint. If the allocation provided by the immediately preceding sentence is unavailable for any reason, the Company and the Underwriters shall contribute in such proportion as is appropriate to reflect not only such relative benefits but also 16 the relative fault of the Company on the one hand and of the Underwriters on the other in connection with the statements or omissions which resulted in such Losses, as well as any other relevant equitable considerations. Benefits received by the Company shall be deemed to be equal to the total net proceeds from the offering (before deducting expenses) received by it, and benefits received by the Underwriters shall be deemed to be equal to the total underwriting discounts and commissions in each case set forth on the cover of the Prospectus Supplement. Relative fault shall be determined by reference to, among other things, whether any untrue or any alleged untrue statement of a material fact or the omission or alleged omission to state a material fact relates to information provided by the Company on the one hand or the Underwriters on the other, the intent of the parties and their relative knowledge, information and opportunity to correct or prevent such untrue statement or omission. The Company and the Underwriters agree that it would not be just and equitable if contribution were determined by pro rata allocation or any other method of allocation which does not take account of the equitable considerations referred to above. Notwithstanding the provisions of this paragraph (d), no person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Act) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation. For purposes of this Section 7, each person who controls an Underwriter within the meaning of either the Act or the Exchange Act and each director, member, officer, employee and agent of an Underwriter shall have the same rights to contribution as such Underwriter, and each person who controls the Company within the meaning of either the Act or the Exchange Act and each officer, director, member, employee or agent of the Company shall have the same rights to contribution as the Company, subject in each case to the applicable terms and conditions of this paragraph (d); 8. Default by an Underwriter. If any one or more Underwriters shall fail to purchase and pay for any of the Bonds agreed to be purchased by such Underwriter hereunder and such failure to purchase shall constitute a default in the performance of its or their obligations under this Agreement, the remaining Underwriters shall be obligated severally to take up and pay for (in the respective proportions which the amount of Bonds set forth opposite their names in Schedule I hereto bears to the aggregate amount of Bonds set forth opposite the names of all the remaining Underwriters) the Bonds which the defaulting Underwriter or Underwriters agreed but failed to purchase; provided, however, that in the event that the aggregate amount of Bonds which the defaulting Underwriter or Underwriters agreed but failed to purchase shall exceed 10% of the aggregate amount of Bonds set forth in Schedule I hereto, the remaining Underwriters shall have the right to purchase all, but shall not be under any obligation to purchase any, of the Bonds, and if such nondefaulting Underwriters do not purchase all the Bonds, this Agreement will terminate without liability to any nondefaulting Underwriter or the Company. In the event of a default by any Underwriter as set forth in this Section 8, the Closing Date shall be postponed for such period, not exceeding five Business Days, as the Representatives shall determine in order to effect whatever changes may thereby be made necessary in the Registration Statement or the Prospectus or any amendment or supplement to either thereof, or in any other documents or arrangements, and the Company agrees to file promptly any amendments or supplements to the Registration Statement or the Prospectus which in the opinion of the Representatives may thereby be made necessary. The term "Underwriter" as used in this Agreement shall include any person substituted under this Section with like effect as if such person had originally been a party to this Agreement. Nothing contained in this Agreement shall relieve any defaulting Underwriter of its liability, if any, to the Company or any nondefaulting Underwriter for damages occasioned by its default hereunder. 9. Termination. This Agreement shall be subject to termination in the absolute discretion of the Representatives, by notice given to the Company prior to delivery of and payment 17 for the Bonds, if at any time after the date hereof and prior to the delivery of and payment for the Bonds (i) trading in the common stock of Xcel Energy Inc. shall have been suspended by the Commission or the New York Stock Exchange or trading in securities generally on the New York Stock Exchange shall have been suspended or limited or minimum prices shall have been established on such Exchange; (ii) a banking moratorium shall have been declared either by Federal or New York State authorities; (iii) there shall have occurred a material disruption in commercial banking or securities settlement or clearance services in the United States or Europe; or (iv) there shall have occurred any outbreak or escalation of hostilities, declaration by the United States of a national emergency or war or other calamity or crisis the effect of which on financial markets is such as to make it, in the sole judgment of the Representatives, impracticable or inadvisable to proceed with the offering or delivery of the Bonds as contemplated by the Prospectus. 10. Indemnities to Survive. The respective agreements, representations, warranties, indemnities and other statements of the Company or its officers and of the Underwriters set forth in or made pursuant to this Agreement will remain in full force and effect, regardless of any investigation made by or on behalf of the Underwriters or the Company or any of the officers, directors or controlling persons referred to in Section 7 hereof, and will survive delivery of and payment for the Bonds. The provisions of Sections 6 and 7 hereof shall survive the termination or cancellation of this Agreement. 11. Notices. All communications hereunder will be in writing and effective only on receipt, and, if sent to the Representatives, will be mailed, delivered or telefaxed to Banc One Capital Markets, Inc., at fax no. (312) 732-4773, and confirmed to Banc One Capital Markets, Inc., 1 Bank One Plaza, Suite IL1 0595, 8th Floor, Chicago, Illinois 60670, Attention: Structuring & Execution, and to McDonald Investments Inc., 800 Superior Avenue, Cleveland, Ohio 44114, and to UBS Securities LLC, at fax no. (203) 719-0495, and confirmed to UBS Securities LLC, 677 Washington Blvd., Stamford, Connecticut 06901, Attention: Fixed Income Syndicate; or, if sent to the Company, will be mailed, delivered or telefaxed to Public Service Company of Colorado, 1225 17th Street, Denver, Colorado 80202, Attention: Vice President and Treasurer (fax no.: (612) 215-5445) and confirmed to the General Counsel (fax no.: (612) 215-4501). 12. Successors. This Agreement will inure to the benefit of and be binding upon the parties hereto and their respective successors and the officers and directors and controlling persons referred to in Section 7 hereof, and no other person will have any right or obligation hereunder. 13. Applicable Law. This Agreement will be governed by and construed in accordance with the laws of the State of New York applicable to contracts made and to be performed within the State of New York. 14. Counterparts. This Agreement may be executed in one or more counterparts, each of which shall constitute an original and all of which together shall constitute one and the same instrument. 15. Headings. The section headings used herein are for convenience only and shall not affect the construction hereof. 16. Definitions. The terms which follow, when used in this Agreement, shall have the meanings indicated. 18 "Act" shall mean the Securities Act of 1933, as amended, and the rules and regulations of the Commission promulgated thereunder. "Business Day" shall mean any day other than a Saturday, a Sunday or a legal holiday or a day on which banking institutions or trust companies are authorized or obligated by law to close in the City of New York. "Closing Date" shall have the meaning specified in Section 3 hereof. "Commission" shall mean the Securities and Exchange Commission. "Exchange Act" shall mean the Securities Exchange Act of 1934, as amended, and the rules and regulations of the Commission promulgated thereunder. "Execution Time" shall mean the date and time that this Agreement is executed and delivered by the parties hereto. "GAAP" shall mean United States generally accepted accounting principles applied on a consistent basis. "Mortgage Supplement" shall mean the Supplemental Indenture, dated as of September 1, 2003, between the Company and U.S. Bank Trust National Association, as trustee, supplemental to the PSCO 1939 Mortgage. "Trust Indenture Act" shall mean the Trust Indenture Act of 1939, as amended, and the rules and regulations of the Commission promulgated thereunder. 17. Underwriters' Counsel. The Company and the Underwriters acknowledge that Dewey Ballantine LLP (a) is acting as counsel to the Underwriters in connection with this Agreement and the transactions contemplated hereby and (b) has acted, and may continue to act, as counsel to the Company's parent company, Xcel Energy Inc., and certain of its subsidiaries in connection with certain regulatory matters, and the Company and the Underwriters consent to such representation. 19 If the foregoing is in accordance with your understanding of our agreement, please sign and return to us the enclosed duplicate hereof, whereupon this Agreement and your acceptance shall represent a binding agreement between the Company and the several Underwriters. Very truly yours, PUBLIC SERVICE COMPANY OF COLORADO By: /s/ Benjamin G. S. Fowke III ----------------------------- Name: Benjamin G. S. Fowke III Title: Vice President and Treasurer The foregoing Agreement is hereby confirmed and accepted as of the date first above written. BANC ONE CAPITAL MARKETS, INC. MCDONALD INVESTMENTS INC. UBS SECURITIES LLC For themselves and the other several Underwriters named in Schedule I to the foregoing Agreement. By: UBS SECURITIES LLC By: /s/ Christopher Forshner ---------------------------- Name: Christopher Forshner Title: Executive Director By: /s/ Scott Whitney ---------------------------- Name: Scott Whitney Title: Director SCHEDULE I

Principal Amount Principal Amount of 4.375% First of 5.50% First Collateral Trust Collateral Trust Bonds due 2008 Bonds due 2014 Underwriters to be Purchased to be Purchased ------------ ---------------- ---------------- Banc One Capital Markets, Inc.................................................. $ 80,000,000 $ 73,333,334 McDonald Investments Inc. $ 80,000,000 $ 73,333,333 UBS Securities LLC ............................................................ $ 80,000,000 $ 73,333,333 U.S. Bancorp Piper Jaffray Inc................................................. $ 24,000,000 $ 22,000,000 Wells Fargo Brokerage Services, LLC............................................ $ 24,000,000 $ 22,000,000 Citigroup Global Markets, Inc. ................................................ $ 12,000,000 $ 11,000,000 ---------------- ---------------- Total........................................................ $ 300,000,000 $ 275,000,000

EXHIBIT A-1 FORM OF OPINION OF ANN E. HOPFENBECK Ladies and Gentlemen: For the purpose of rendering this opinion, I have examined the proceedings taken by Public Service Company of Colorado, a Colorado corporation (the "Company"), with respect to the issue and sale by the Company of $ 300,000,000 principal amount of 4.375% First Collateral Trust Bonds, Series No. 14 due 2008 and $ 275,000,000 principal amount of 5.50% First Collateral Trust Bonds, Series No. 15 due 2014 (collectively, the "Bonds"). In connection therewith I have participated in the preparation of the proceedings for the issuance and sale of the Bonds including the Underwriting Agreement dated September 2, 2003, between you and the Company relating to your purchase of the Bonds (the "Agreement"), and have either participated in the preparation of or examined the Trust Indenture dated October 1, 1993, from the Company to U.S. Bank Trust National Association, as successor trustee (the "Trustee"), as heretofore supplemented and as it will be further supplemented by Supplemental Indenture No. 15 creating the Bonds (said indenture, as so supplemented and to be further supplemented, being hereafter referred to as the "Indenture") and the PSCo 1939 Mortgage (as defined in the Indenture). This letter is furnished to the Underwriters pursuant to Section 5(b) of the Agreement. Except as otherwise defined herein, terms used in this letter that are defined in the Agreement are used herein as so defined. I also have participated in the preparation of or examined the registration statement and any amendments thereto and the accompanying prospectuses and any amendments or supplements thereto, as filed under the Act, with respect to the Bonds. My examination has extended to all statutes, records, instruments, and documents which I have deemed necessary to examine for the purposes of this opinion. I am of the opinion that: 1. The Company has been duly incorporated and is validly existing as a corporation in good standing under the laws of the State of Colorado with corporate power and authority to own, lease and operate its properties and conduct its business as described in the Prospectus and to enter into and perform its obligations under the Agreement; 2. The Agreement has been duly authorized, executed and delivered by the Company; 3. The issuance and sale of the Bonds, and the issuance and delivery of the Class A Bonds, have been duly authorized and approved by an order of The Public Utilities Commission of the State of Colorado and such order is final and in full force and effect on the date hereof, the time for appeal therefrom or review thereof or intervention with respect thereto having expired; no further approval, authorization, consent or other order of any public board or body in the State of Colorado is legally required in connection with the transactions contemplated by the Agreement, the Indenture or the PSCo 1939 Mortgage, except as may be required under the blue sky laws of any jurisdiction in connection with the purchase and distribution of the Bonds by the Underwriters in the manner contemplated by the Agreement and in the Prospectus; A-1-1 4. Neither the execution and delivery of the Agreement, the issue and sale of the Bonds, nor the consummation of any other of the transactions therein contemplated, nor the fulfillment of the terms thereof will conflict with, result in a breach or violation or imposition of any lien, charge or encumbrance upon any property or assets of the Company or any of its subsidiaries, other than the security interest created by the Bonds, the Indenture and the PSCo 1939 Mortgage, under (i) the Restated Articles of Incorporation, as amended, or By-Laws of the Company or any of its subsidiaries; (ii) the terms of any indenture, contract, lease, mortgage, deed of trust, note agreement, loan agreement or other agreement, obligation, condition, covenant or instrument to which the Company or any of its subsidiaries is a party or bound or to which its or their property is subject; or (iii) any statute, law, rule, regulation, judgment, order or decree applicable to the Company or any of its subsidiaries of any court, regulatory body, administrative agency, governmental body, arbitrator or other authority having jurisdiction over the Company or any of its subsidiaries or any of its or their properties except, in the case of clause (ii) or (iii), any such conflict, breach or violation, if it did exist, would not, individually or in the aggregate, have a material adverse change in the condition (financial or otherwise), prospects, earnings, business or properties of the Company and its subsidiaries taken as a whole, whether or not arising from transactions in the ordinary course of business; 5. The facsimile signature of a Senior Vice President or Vice President of the Company in lieu of his manual signature on the Bonds and the Class A Bonds and the facsimile signature of the Secretary or an Assistant Secretary of the Company attesting the corporate seal in lieu of his manual signature on the Bonds and the Class A Bonds have been duly and properly authorized by the Board of Directors of the Company, are not inconsistent with the provisions of the Restated Articles of Incorporation, as amended, or By-Laws of the Company and are valid and effective under the laws of the State of Colorado; and the facsimile signatures of such officers on the Bonds and the Class A Bonds have the same legal effect as though they had manually signed and attested the Bonds and the Class A Bonds as such respective officers; 6. The descriptions in the Registration Statement and Prospectus of Colorado state statutes and legal and governmental proceedings are accurate in all material respects; to the best of my knowledge, there are no franchises, contracts, indentures, mortgages, loan agreements, notes, leases or other instruments that would be required to be described in the documents incorporated by reference in the Prospects that are not described or referred to in such incorporated documents, and the descriptions thereof or references thereto are correct in all material respects; 7. There is no pending, or to my knowledge, threatened suit or proceeding before any court or governmental agency, authority or body or any arbitration involving the Company or any of its subsidiaries required to be disclosed in the Prospectus which is not adequately disclosed in the Prospectus; and 8. The franchises held by the Company, together with the applicable Certificates of Convenience and Necessity issued by The Public Utilities Commission of the State of Colorado, give the Company all necessary authority for the maintenance and operation of its properties and business as now conducted, and are free from burdensome restrictions or conditions of an unusual character. In the course of my participation in the preparation or examination of the Registration Statement and any amendments thereto and the Prospectus and any amendments or supplements thereto A-1-2 I made investigations as to the accuracy of certain of the statements of fact contained therein, I discussed other matters with officers, employees, and representatives of the Company, and I examined various corporate records and data. While I do not pass upon or assume responsibility for, and shall not be deemed to have independently verified, the accuracy and completeness of the statements contained in the Registration Statement or the Prospectus (except as to matters set forth in paragraphs 6 and 7 above), nothing has come to my attention that would lead me to believe that the Registration Statement, at the time it became effective, contained an untrue statement of a material fact or omitted to state a material fact required to be stated therein or necessary in order to make the statements therein, not misleading, or that the Prospectus, at the time it was filed with the Commission pursuant to Rule 424(b) under the Act and at the date hereof, contained or contains an untrue statement of material fact or omitted or omits to state a material fact necessary in order to make the statements therein, in light of the circumstances under which they were made, not misleading. My opinions herein are limited to the laws of the State of Colorado. For purposes of rendering their opinion of even date herewith to the Underwriters, Dewey Ballantine LLP are entitled to rely on my opinions in paragraphs 1, 2 and 3 above as to all matters of Colorado law as if such opinions were addressed to them. Respectfully submitted, By: ____________________________________ Ann E. Hopfenbeck Assistant General Counsel Xcel Energy Services, Inc. A-1-3 EXHIBIT A-2 FORM OF OPINION OF JONES DAY Ladies and Gentlemen: We have acted as special counsel to Public Service Company of Colorado, a Colorado corporation (the "Company"), in connection with the sale by the Company pursuant to the Underwriting Agreement, dated as of September 2, 2003 (the "Agreement"), by and among the Company and the Underwriters named on Schedule I thereto (the "Underwriters"), for whom you are acting as representatives (the "Representatives"), of $300,000,000 aggregate principal amount of 4.375% First Collateral Trust Bonds, Series 14 due 2008, and $275,000,000 aggregate principal amount of 5.50% First Collateral Trust Bonds, Series 15 due 2014 of the Company (collectively, the "Bonds") being issued on this date under the Company's Indenture, dated as of October 1, 1993, to U.S. Bank Trust National Association, as successor trustee (the "Trustee"), as heretofore supplemented and as it is being further supplemented by a supplemental indenture creating the Bonds (said Indenture, as so supplemented, being hereafter referred to as the "Indenture"). This letter is furnished to the Underwriters pursuant to Section 5(b) of the Agreement. Except as otherwise defined herein, terms used in this letter that are defined in the Agreement are used herein as so defined. In connection with the opinions expressed herein, we have examined such documents and records, including an examination of originals or copies certified or otherwise identified to our satisfaction, and matters of law as we have deemed necessary for purposes of this opinion. Based upon the foregoing and subject to the further assumptions, qualifications and limitations stated herein, we are of the opinion that: 1. Assuming that the Agreement has been duly (a) authorized by the Company and (b) executed and delivered by the Company under Colorado law, the Agreement has been duly executed and delivered by the Company to the extent such execution and delivery are questions of New York law. 2. The Company is not, and after giving effect to the offering and sale of the Bonds and the application of the proceeds thereof as described in the Prospectus will not be, an "investment company" or an entity "controlled" by an "investment company" within the meaning of the Investment Company Act of 1940, as amended, without taking account of any exemption arising out of the number of holders of the Company's securities. 3. Assuming that the issuance and sale of the Bonds, and the issuance and delivery of the Class A Bonds, have been duly authorized and approved by an order of The Public Utilities Commission of the State of Colorado and such order is final and in full force and effect on the date hereof, and that the time for appeal therefrom or review thereof or intervention with respect thereto have expired, no approval, authorization, consent or order of any public board or body under the laws of the United States of America is legally required in connection with the transactions contemplated by the Agreement, the Indenture or the PSCo 1939 Mortgage, except those that already have been obtained and are in full force and effect. A-2-1 4. The Registration Statement has been declared effective by the Commission under the Act, the Prospectus has been filed with the Commission pursuant to Rule 424(b) under the Act in the manner and within the time period required by Rule 424(b) under the Act; and no stop order suspending the effectiveness of the Registration Statement has been issued under the Act and, to the best of our knowledge, no proceedings for that purpose have been instituted or are pending or are threatened by the Commission; 5. Except as to the financial statements or other financial or statistical data included or incorporated by reference therein, as to which we express no opinion, the Registration Statement, at the time it became effective, and the Prospectus, at the time it was filed with the Commission pursuant to Rule 424(b), complied as to form in all material respects with the applicable requirements of the Act and the Trust Indenture Act. 6. Except as to the financial statements or other financial or statistical data included or incorporated by reference therein, as to which we express no opinion, the documents incorporated by reference in the Prospectus, when they were filed with the Commission, compiled as to form in all material respects with the applicable requirements of the Exchange Act. 7. The descriptions in the Registration Statement and the Prospectus of United States federal statutes are accurate and fairly present the information purported to be given. We have not independently verified and are not passing upon, and do not assume any responsibility for, the accuracy, completeness or fairness, except and to the extent as set forth in paragraph 8 above, of the information included in the Registration Statement or Prospectus. We have participated in the preparation of the Registration Statement and Prospectus. From time to time in connection therewith, we have had discussions with officers, directors and employees of the Company and Xcel Energy Inc., a Minnesota corporation and the parent corporation of the Company, with representatives of Deloitte & Touche LLP, the independent accountants who examined certain of the financial statements of the Company, and with the Underwriters and counsel to the Underwriters. Based upon our participation and discussions described above, nothing has come to our attention that would lead us to believe that the Registration Statement, at the time it became effective, contained an untrue statement of a material fact or omitted to state a material fact required to be stated therein or necessary in order to make the statements therein, not misleading, or that the Prospectus, at the time it was filed with the Commission pursuant to Rule 424(b) under the Act and at the date hereof, contained or contains an untrue statement of material fact or omitted or omits to state a material fact necessary in order to make the statements therein, in light of the circumstances under which they were made, not misleading (except that we express no view as to the financial statements, financial schedules and other financial data included or incorporated by reference in the Prospectus). The opinions and views set forth above are subject to the following assumptions, qualifications and limitations: We have assumed, for purposes of the opinions and views expressed herein, the legal capacity of all natural persons executing documents, the genuineness of all signatures, the authenticity of original and certified documents and the conformity to original or certified copies of all copies submitted to us as conformed or reproduction copies. For the purposes of the opinions and views expressed herein, we also have assumed that each of the Underwriters and the Trustee has duly authorized, executed and delivered the documents to which each of them is a party and that each of A-2-2 such documents is the valid, binding and enforceable obligation of each of the Underwriters and the Trustee, respectively. Our examination of matters of law in connection with the opinions expressed herein have been limited to, and accordingly our opinions herein are limited to, the federal laws of the United States of America and the laws of the State of New York, in each case as currently in effect. In connection with our opinions set forth herein, we express no opinion as to any matters of, or that relate to, the laws of any other jurisdiction, including the laws of the State of Colorado. To the extent such opinions relate to any provision of Colorado law, we direct you to the opinion dated the date hereof of Ann E. Hopfenbeck, Esq., Assistant General Counsel of Xcel Energy Services, Inc. and a member of the Colorado bar, which opinion previously has been delivered to you. It should be understood that the scope of our representation does not include providing legal services to any financial institution or financial institution-affiliated party with regard to any matter (a "financial institutions regulatory matter") the resolution of which requires reference to any provision of Title 12 of the United States Code as in effect from time to time, the policies, procedures, guidelines or practices of any state regulator with respect to any such federal or state law or regulation, or any other federal or state law or regulation or regulatory policy, procedure or practice expressly applicable to financial institutions or, in their capacities as such, financial institution-affiliated parties or, if not expressly applicable, then to the extent applicable by implication or actually applied to a financial institution or financial institution-affiliated party. We express no opinion regarding the compliance by any Underwriter with any such financial institutions regulatory matter. This letter is furnished by us, as special counsel to the Company, to you, as the Representatives, solely for the benefit of the Underwriters and solely with respect to the purchase of the Bonds from the Company by the Underwriters upon the understanding that we are not hereby assuming any professional responsibility to any other person whatsoever, and that this letter is not to be used, circulated, quoted or otherwise referred to for any other purpose. Very truly yours, A-2-3 EXHIBIT A-3 FORM OF OPINION OF LEBOEUF, LAMB, GREENE & MACRAE, L.L.P. Ladies and Gentlemen: We have acted as counsel to Public Service Company of Colorado (the "Company"), with respect to matters relating to the Indenture dated as of December 31, 1939 (the "1939 PSCo Mortgage") between the Company and U.S. Bank Trust National Association (formerly First Trust of New York, National Association), as successor trustee (the "1939 Trustee"), and the Indenture dated as of October 1, 1993, as amended and supplemented (the "Indenture"), between the Company and U.S. Bank Trust National Association (formerly First Trust of New York, National Association), as successor trustee (the "Trustee") in connection with the sale by the Company of $300,000,000 aggregate principal amount of its First Collateral Trust Bonds, Series No. 14 due 2008 and $275,000,000 aggregate principal amount of its First Collateral Trust Bonds, Series No. 15 due 2014 (collectively, the "Bonds") on the basis of an equivalent amount of Class A Bonds (as defined in the Indenture). This opinion is being delivered pursuant to Section 5(b) of the Underwriting Agreement, dated September 2, 2003 (the "Agreement"), between the Company and you as representatives of the Underwriters (the "Representatives"). Unless otherwise stated, defined terms used herein shall have the respective meanings given to them in the Agreement. We are not general counsel to the Company and our representation of the Company consists of advising it with respect to corporate and regulatory matters as to which we have been specifically consulted. We are familiar with the legal matters pertaining to, and the corporate proceedings of the Company taken with respect to, the authorization and the issuance and sale by the Company of the Bonds and the authorization and the issuance and delivery by the Company of the Class A Bonds. We have examined, among other things, the Registration Statement and Prospectus and any amendment and supplement thereto, the corporate records of the Company, the Indenture (including the Supplemental Indenture creating the Bonds), the PSCo 1939 Mortgage (including the supplemental indenture thereto under which the Class A Bonds are being issued), and such other proceedings, papers and documents as we have deemed relevant for the purposes of rendering the opinions enumerated below. In such examination, we have assumed the genuineness of all signatures, the authenticity of all documents submitted to us as originals, the conformity to the original documents of all documents submitted to us as copies and the authenticity of all such latter documents. We have relied as to various questions of fact upon discussions with officers and representatives of the Company and the representations and warranties of the Company contained in the Agreement and upon the certificates of public officials and of officers of the Company being delivered to you thereunder. With respect to the opinions expressed in paragraphs 5, 6 and 7 below, we have relied upon information obtained from public records and from the Company. On the basis of and subject to the foregoing, and subject to the further limitations and qualifications set forth below, it is our opinion that: 1. The Indenture has been duly and validly authorized, executed and delivered by the Company and is in due and proper form and (assuming the Indenture has been duly authorized, executed and delivered by the Trustee) constitutes a legal, valid and binding A-2-1 mortgage of the Company, enforceable in accordance with its terms, subject to bankruptcy, insolvency, moratorium, fraudulent conveyance and transfer, and other similar laws affecting the rights of mortgagees and creditors generally, state laws which affect the enforcement of certain remedial provisions of the Indenture, and general principles of equity (regardless of whether such principles are considered in a proceeding at law or in equity); provided, however, that such state laws which affect the enforcement of certain remedial provisions of the Indenture will not, in our opinion, render the remedies afforded by the Indenture inadequate for the practical realization of the benefit of the security provided thereby; 2. The Bonds are in due and proper form and the issuance and sale of the Bonds have been duly authorized by all necessary corporate action, and when duly executed, authenticated and delivered to the Underwriters pursuant to the Agreement against payment of the consideration set forth therein, the Bonds will be legal, valid and binding obligations of the Company enforceable (subject to the exceptions and limitations referred to in paragraph 1 hereof) in accordance with their terms and entitled to the benefits and security of the Indenture; and the Bonds will be secured equally and ratably with all other bonds outstanding under the Indenture; 3. The PSCo 1939 Mortgage has been duly and validly authorized, executed and delivered by the Company and is in due and proper form and (assuming the PSCo 1939 Mortgage has been duly authorized, executed and delivered by the 1939 Trustee) constitutes a legal, valid and binding mortgage of the Company, enforceable in accordance with its terms, subject to bankruptcy, insolvency, moratorium, fraudulent conveyance and transfer, and other similar laws affecting the rights of mortgagees and creditors generally, state laws which affect the enforcement of certain remedial provisions of the PSCo 1939 Mortgage and general principles of equity (regardless of whether such principles are considered in a proceeding at law or in equity); provided, however, that such state laws which affect the enforcement of certain remedial provisions of the Indenture will not, in our opinion, render the remedies afforded by the PSCo 1939 Mortgage inadequate for the practical realization of the benefit of the security provided thereby; 4. The Class A Bonds are in due and proper form and the issuance and delivery of the Class A Bonds have been duly authorized by all necessary corporate action; and when (a) the Class A Bonds have been duly executed, authenticated and delivered to the Trustee pursuant to the PSCo 1939 Mortgage and (b) the Bonds have been duly executed, authenticated and delivered to the Underwriters pursuant to the Agreement against payment of the consideration set forth therein, the Class A Bonds will be legal, valid and binding obligations of the Company enforceable (subject to the exceptions and limitations referred to in paragraph 3 hereof) in accordance with their terms and entitled to the benefits and security of the PSCo 1939 Mortgage; and the Class A Bonds will be secured equally and ratably with all other bonds outstanding under the PSCo 1939 Mortgage (except to the extent that any sinking, amortization, improvement or other fund may afford additional security for such bonds of any particular series); 5. The Company has good title to the real properties specifically or generally described or referred to in the Indenture and in the PSCo 1939 Mortgage as subject to the respective liens thereof (except such real property as may have been sold, exchanged or otherwise disposed of), subject only to (a) in the case of all such properties, the lien of the PSCo 1939 Mortgage and "permitted encumbrances" (as defined in the PSCo 1939 Mortgage) and (b) A-2-2 in the case of such properties which are used or to be used in or in connection with the Electric Utility Business (as defined in the Indenture) (whether or not such use is the sole use of such property), the lien of the Indenture and Permitted Liens (as defined in the Indenture); 6. The Indenture and the filings and recordations made in connection therewith constitute a mortgage lien on the properties specifically or generally described or referred to therein as subject to the lien thereof (except such properties as may have been sold, exchanged or otherwise disposed of or released from the lien thereof in accordance with the terms thereof), subject to no liens prior to the lien of the Indenture other than Permitted Liens and the lien of the PSCo 1939 Mortgage; and the Indenture by its terms effectively subjects to the lien thereof all property (except property of the kinds specifically excepted from the lien of the Indenture by the terms thereof) acquired by the Company after the date of execution and delivery of the Indenture and used or to be used in or in connection with the Electric Utility Business, subject to Permitted Liens, the lien of the PSCo 1939 Mortgage, any lien thereon existing at the time of such acquisition and to any liens for unpaid portions of the purchase money placed thereon at the time of such acquisition, and also subject to the provisions of Article Thirteen of the Indenture and to certain possible claims of a trustee in bankruptcy and possible claims and taxes of the federal government; 7. The PSCo 1939 Mortgage and the filings and recordations made in connection therewith constitute a first mortgage lien on the properties specifically or generally described or referred to therein as subject to the lien thereof (except such property as may have been sold, exchanged or otherwise disposed of or released from the lien thereof in accordance with the terms thereof), and, with respect to the shares of stock pledged thereunder, the PSCo 1939 Mortgage and the possession by the Trustee of such stock and appropriate stock powers in the State of New York pursuant to the PSCo 1939 Mortgage is sufficient to create a security interest under Article 9 of the Uniform Commercial Code as in effect in the State of New York with respect to such stock (except such stock as may have been sold, exchanged or otherwise disposed of or released from the lien thereof in accordance with the terms thereof), subject to no liens or security interests prior to the lien and security interest created by the PSCo 1939 Mortgage other than "permitted encumbrances"; and the PSCo 1939 Mortgage by its terms effectively subjects to the lien or security interest thereof all property (except property of the kinds specifically excepted from the lien of the PSCo 1939 Mortgage by the terms thereof) acquired by the Company after the date of execution and delivery of the PSCo 1939 Mortgage, subject to "permitted encumbrances", to any lien thereon existing at the time of such acquisition and to any liens for unpaid portions of the purchase money placed thereon at the time of acquisition and also subject to the provisions of Article XI of the PSCo 1939 Mortgage and to certain possible claims of a trustee in bankruptcy and possible claims and taxes of the federal government; and 8. The Bonds, the Indenture, the Class A Bonds, and the PSCo 1939 Mortgage conform as to legal matters to the descriptions of the terms thereof contained in the Prospectus under the captions "Supplemental Description of the First Collateral Trust Bonds," "Description of the First Collateral Trust Bonds" and "Description of the 1939 Mortgage". This opinion is limited to the laws of the State of New York and the State of Colorado and the federal law of the United States of America. This opinion speaks as of the date hereof and we undertake no responsibility to advise you of any change in circumstances after the date hereof. A-2-3 Dewey Ballantine LLP is hereby authorized to rely upon paragraphs 1, 2, 3, 4 and 8 of this letter as to matters governed by the law of the State of Colorado as if this letter, solely with respect to aforementioned paragraphs, were addressed to them. This letter is not being delivered for the benefit of, nor may it be relied upon by, the holders of the Bonds or any other party to which it is not specifically addressed or to which reliance has not expressly been permitted hereby. This letter may be relied upon only by the addressees hereof in connection with the issuance and sale of the Bonds and may not be relied upon for any other purpose. Very truly yours, A-2-4 EXHIBIT B FORM OF LETTER OF DELOITTE & TOUCHE LLP A-3-1 EX-4.01 4 c79426exv4w01.txt EX-4.01 SUPPLEMENTAL INDENTURE SUPPLEMENTAL INDENTURE (DATED AS OF SEPTEMBER 1, 2003) -------------- PUBLIC SERVICE COMPANY OF COLORADO TO U.S. BANK TRUST NATIONAL ASSOCIATION, AS TRUSTEE -------------- CREATING TWO ISSUES OF FIRST MORTGAGE BONDS, COLLATERAL SERIES N AND COLLATERAL SERIES O -------------- (SUPPLEMENTAL TO INDENTURE DATED AS OF DECEMBER 1, 1939, AS AMENDED) SUPPLEMENTAL INDENTURE, dated as of September 1, 2003, between PUBLIC SERVICE COMPANY OF COLORADO, a corporation organized and existing under the laws of the State of Colorado (the "Company"), party of the first part, and U.S. BANK TRUST NATIONAL ASSOCIATION (FORMERLY FIRST TRUST OF NEW YORK, NATIONAL ASSOCIATION), a national banking association, as successor trustee (the "Trustee") to Morgan Guaranty Trust Company of New York (formerly Guaranty Trust Company of New York), party of the second part. WHEREAS, the Company heretofore executed and delivered to the Trustee its Indenture, dated as of December 1, 1939 (the "Principal Indenture"), to secure its First Mortgage Bonds from time to time issued thereunder; and WHEREAS, the Company has heretofore executed and delivered to the Trustee the Supplemental Indentures referred to in Schedule A hereto for certain purposes, including the creation of series of bonds, the subjection to the lien of the Principal Indenture of property acquired after the execution and delivery thereof, the amendment of certain provisions of the Principal Indenture and the appointment of the successor Trustee; and WHEREAS, the Principal Indenture as supplemented and amended by all Supplemental Indentures heretofore executed by the Company and the Trustee is hereinafter referred to as the "Indenture", and, unless the context requires otherwise, references herein to Articles and Sections of the Indenture shall be to Articles and Sections of the Principal Indenture as so amended; and WHEREAS, the Company proposes to create two new series of First Mortgage Bonds to be designated as First Mortgage Bonds, Collateral Series N (the "Collateral Series N Bonds") and First Mortgage Bonds, Collateral Series O (the "Collateral Series O Bonds"), to be issued and delivered to the trustee under the 1993 Mortgage (as hereinafter defined) as the basis for the authentication and delivery under the 1993 Mortgage of First Collateral Trust Bonds, Series No. 14 and First Collateral Trust Bonds, Series No. 15, respectively, all as hereinafter provided, and to vary in certain respects the covenants and provisions contained in Article V of the Indenture, to the extent that such covenants and provisions apply to the Collateral Series N Bonds and the Collateral Series O Bonds; and WHEREAS, the Company, pursuant to the provisions of the Indenture, has, by appropriate corporate action, duly resolved and determined to execute this Supplemental Indenture for the purpose of providing for the creation of the Collateral Series N Bonds and the Collateral Series O Bonds and of specifying the form, provisions and particulars thereof, as in the Indenture provided or permitted and of giving to the Collateral Series N Bonds and the Collateral Series O Bonds the protection and security of the Indenture; and WHEREAS, the Company represents that all acts and proceedings required by law and by the charter and by-laws of the Company, including all action requisite on the part of its shareholders, directors and officers, necessary to make the Collateral Series N Bonds and the Collateral Series O Bonds , when executed by the Company, authenticated and delivered by the Trustee and duly issued, the valid, binding and legal obligations of the Company, and to constitute the Principal Indenture and all indentures supplemental thereto, including this 1 Supplemental Indenture, valid, binding and legal instruments for the security of the bonds of all series, including the Collateral Series N Bonds and the Collateral Series O Bonds , in accordance with the terms of such bonds and such instruments, have been done, performed and fulfilled, and the execution and delivery hereof have been in all respects duly authorized; NOW, THEREFORE, THIS SUPPLEMENTAL INDENTURE WITNESSETH: That Public Service Company of Colorado, the Company named in the Indenture, in consideration of the premises and of One Dollar to it duly paid by the Trustee at or before the ensealing and delivery of these presents, the receipt whereof is hereby acknowledged, and in pursuance of the direction and authority of the Board of Directors of the Company given at a meeting thereof duly called and held, and in order to create the Collateral Series N Bonds and the Collateral Series O Bonds and to specify the form, terms and provisions thereof, and to secure the payment of the principal of and premium, if any, and interest, if any, on all bonds from time to time outstanding under the Indenture, including the Collateral Series N Bonds and the Collateral Series O Bonds, according to the terms of said bonds, and to secure the performance and observance of all of the covenants and conditions contained in the Indenture, has executed and delivered this Supplemental Indenture and has granted, bargained, sold, warranted, aliened, remised, released, conveyed, assigned, transferred, mortgaged, pledged, set over and confirmed unto U.S. Bank Trust National Association, as Trustee, and its successor or successors in the trust and its and their assigns forever; TO HAVE AND TO HOLD all and singular the properties, rights, privileges and franchises described in the Principal Indenture and in the several Supplemental Indentures hereinabove referred to and owned by the Company on the date of the execution and delivery hereof (other than property of a character expressly excepted from the lien of the Indenture as therein set forth) unto the Trustee and its successor or successors and assigns forever; SUBJECT, HOWEVER, to permitted encumbrances as defined in the Indenture; IN TRUST, NEVERTHELESS, upon the terms and trusts set forth in the Indenture, for the equal and proportionate benefit and security of all present and future holders of the bonds and coupons issued and to be issued under the Indenture, including the Collateral Series N Bonds and the Collateral Series O Bonds, without preference, priority or distinction as to lien (except as any sinking, amortization, improvement or other fund established in accordance with the provisions of the Indenture or any indenture supplemental thereto may afford additional security for the bonds of any particular series) of any of said bonds over any others thereof by reason of series, priority in the time of the issue or negotiation thereof, or otherwise howsoever, except as provided in Section 2 of Article IV of the Indenture. ARTICLE ONE CREATION AND DESCRIPTION OF THE COLLATERAL SERIES N BONDS SECTION 1. A new series of bonds to be issued under and secured by the Indenture is hereby created, the bonds of such new series to be designated First Mortgage Bonds, Collateral Series N. The Collateral Series N Bonds shall be limited to an aggregate principal 2 amount of Three Hundred Million dollars ($300,000,000). The Collateral Series N Bonds shall mature on October 1, 2008. The Collateral Series N Bonds shall not bear interest. The principal of each of the Collateral Series N Bonds shall be payable, upon presentation thereof, at the office or agency of the Company in the city in which the principal corporate trust office of the 1993 Mortgage Trustee (as hereinafter defined) is located, in any coin or currency of the United States of America which at the time of payment shall be legal tender for the payment of public and private debts. The Collateral Series N Bonds shall be issued and delivered by the Company to U.S. Bank Trust National Association, as successor trustee under the Indenture, dated as of October 1, 1993, as supplemented (the "1993 Mortgage"), of the Company to such successor trustee (the "1993 Mortgage Trustee"), as the basis for the authentication and delivery under the 1993 Mortgage of First Collateral Trust Bonds, Series No. 14. As provided in the 1993 Mortgage, the Collateral Series N Bonds will be registered in the name of the 1993 Mortgage Trustee or its nominee and will be owned and held by the 1993 Mortgage Trustee, subject to the provisions of the 1993 Mortgage, for the benefit of the holders of all securities from time to time outstanding under the 1993 Mortgage, and the Company shall have no interest therein. Any payment by the Company under the 1993 Mortgage of the principal of the securities which shall have been authenticated and delivered under the 1993 Mortgage on the basis of the issuance and delivery to the 1993 Mortgage Trustee of Collateral Series N Bonds (other than by the application of the proceeds of a payment in respect of such Collateral Series N Bonds), shall, to the extent thereof, be deemed to satisfy and discharge the obligation of the Company, if any, to make a payment of principal of such Collateral Series N Bonds which is then due. The Trustee may conclusively presume that the obligation of the Company to pay the principal of the Collateral Series N Bonds as the same shall become due and payable shall have been fully satisfied and discharged unless and until it shall have received a written notice from the 1993 Mortgage Trustee, signed by an authorized officer thereof, stating that the principal of specified Collateral Series N Bonds has become due and payable and has not been fully paid, and specifying the amount of funds required to make such payment. Each Collateral Series N Bond shall be dated as of the date of its authentication. The Collateral Series N Bonds shall be issued as fully registered bonds only, in denominations of $1,000 and multiples thereof. The Collateral Series N Bonds shall be registerable and exchangeable at the office or agency of the Company in the city in which the principal corporate trust office of the 1993 Mortgage Trustee is located, in the manner and upon the terms set forth in Section 5 of Article II of the Indenture; provided, however, that none of the Collateral Series N Bonds shall be transferable except to a successor trustee under the 1993 Mortgage. No service charge shall be made for any exchange or transfer of any Collateral Series N Bond. SECTION 2. The text of the Collateral Series N Bonds shall be substantially in the form attached hereto as Exhibit A. 3 SECTION 3. The Collateral Series N Bonds may be executed by the Company and delivered to the Trustee and, upon compliance with all applicable provisions and requirements of the Indenture in respect thereof, shall be authenticated by the Trustee and delivered (without awaiting the filing or recording of this Supplemental Indenture) in accordance with the written order or orders of the Company. ARTICLE TWO CREATION AND DESCRIPTION OF THE COLLATERAL SERIES O BONDS SECTION 1. A new series of bonds to be issued under and secured by the Indenture is hereby created, the bonds of such new series to be designated First Mortgage Bonds, Collateral Series O. The Collateral Series O Bonds shall be limited to an aggregate principal amount of Two Hundred Seventy-Five Million dollars ($275,000,000). The Collateral Series O Bonds shall mature on April 1, 2014. The Collateral Series O Bonds shall not bear interest. The principal of each of the Collateral Series O Bonds shall be payable, upon presentation thereof, at the office or agency of the Company in the city in which the principal corporate trust office of the 1993 Mortgage Trustee is located, in any coin or currency of the United States of America which at the time of payment shall be legal tender for the payment of public and private debts. The Collateral Series O Bonds shall be issued and delivered by the Company to the 1993 Mortgage Trustee, as the basis for the authentication and delivery under the 1993 Mortgage of First Collateral Trust Bonds, Series No. 15. As provided in the 1993 Mortgage, the Collateral Series O Bonds will be registered in the name of the 1993 Mortgage Trustee or its nominee and will be owned and held by the 1993 Mortgage Trustee, subject to the provisions of the 1993 Mortgage, for the benefit of the holders of all securities from time to time outstanding under the 1993 Mortgage, and the Company shall have no interest therein. Any payment by the Company under the 1993 Mortgage of the principal of the securities which shall have been authenticated and delivered under the 1993 Mortgage on the basis of the issuance and delivery to the 1993 Mortgage Trustee of Collateral Series O Bonds (other than by the application of the proceeds of a payment in respect of such Collateral Series O Bonds), shall, to the extent thereof, be deemed to satisfy and discharge the obligation of the Company, if any, to make a payment of principal of such Collateral Series O Bonds which is then due. The Trustee may conclusively presume that the obligation of the Company to pay the principal of the Collateral Series O Bonds as the same shall become due and payable shall have been fully satisfied and discharged unless and until it shall have received a written notice from the 1993 Mortgage Trustee, signed by an authorized officer thereof, stating that the principal of specified Collateral Series O Bonds has become due and payable and has not been fully paid, and specifying the amount of funds required to make such payment. Each Collateral Series O Bond shall be dated as of the date of its authentication. 4 The Collateral Series O Bonds shall be issued as fully registered bonds only, in denominations of $1,000 and multiples thereof. The Collateral Series O Bonds shall be registerable and exchangeable at the office or agency of the Company in the city in which the principal corporate trust office of the 1993 Mortgage Trustee is located, in the manner and upon the terms set forth in Section 5 of Article II of the Indenture; provided, however, that none of the Collateral Series O Bonds shall be transferable except to a successor trustee under the 1993 Mortgage. No service charge shall be made for any exchange or transfer of any Collateral Series O Bond. SECTION 2. The text of the Collateral Series O Bonds shall be substantially in the form attached hereto as Exhibit B. SECTION 3. The Collateral Series O Bonds may be executed by the Company and delivered to the Trustee and, upon compliance with all applicable provisions and requirements of the Indenture in respect thereof, shall be authenticated by the Trustee and delivered (without awaiting the filing or recording of this Supplemental Indenture) in accordance with the written order or orders of the Company. ARTICLE THREE REDEMPTION OF THE COLLATERAL SERIES N BONDS AND THE COLLATERAL SERIES O BONDS SECTION 1. Each Collateral Series N Bond and Collateral Series Bond shall be redeemable at the option of the Company in whole at any time, or in part from time to time, prior to maturity, at a redemption price equal to 100% of the principal amount thereof to be redeemed. SECTION 2. The provisions of Sections 3, 4, 5, 6 and 7 of Article V of the Indenture shall be applicable to the Collateral Series N Bonds and the Collateral Series O Bonds, except that (a) no publication of notice of redemption of the Collateral Series N Bonds or the Collateral Series O Bonds shall be required and (b) if less than all the Collateral Series N Bonds or the Collateral Series O Bonds are to be redeemed, the Collateral Series N Bonds or the Collateral Series O Bonds to be redeemed shall be selected in the principal amounts designated to the Trustee by the Company, and except as such provisions may otherwise be inconsistent with the provisions of this Article Three. SECTION 3. The holder of each and every Collateral Series N Bond and Collateral Series O Bond hereby agrees to accept payment thereof prior to maturity on the terms and conditions provided for in this Article Three. 5 ARTICLE FOUR ACKNOWLEDGMENT OF RIGHT TO VOTE OR CONSENT WITH RESPECT TO CERTAIN AMENDMENTS TO INDENTURE The Company hereby acknowledges the right of the holders of the Collateral Series N Bonds and the Collateral Series O Bonds to vote or consent with respect to any or all of the modifications to the Indenture referred to in Article Three of the Supplemental Indenture, dated as of March 1, 1980, irrespective of the fact that the Bonds of the Second 1987 Series are no longer outstanding; provided, however, that such acknowledgment shall not impair (a) the right of the Company to make such modifications without the consent or other action of the holders of the Bonds of the 2020 Series or the bonds of any other series subsequently created under the Indenture with respect to which the Company has expressly reserved such right or (b) the right of the Company to reserve the right to make such modifications without the consent or other action of the holders of bonds of one or more, or any or all, series created subsequent to the creation of the Collateral Series N Bonds and the Collateral Series O Bonds. ARTICLE FIVE THE TRUSTEE The Trustee accepts the trusts created by this Supplemental Indenture upon the terms and conditions set forth in the Indenture and this Supplemental Indenture. The recitals in this Supplemental Indenture are made by the Company only and not by the Trustee. Each and every term and condition contained in Article XII of the Indenture shall apply to this Supplemental Indenture with the same force and effect as if the same were herein set forth in full, with such omissions, variations and modifications thereof as may be appropriate to make the same conform to this Supplemental Indenture. ARTICLE SIX MISCELLANEOUS PROVISIONS SECTION 1. Subject to the variations contained in Article Three of this Supplemental Indenture, the Indenture is in all respects ratified and confirmed and the Principal Indenture, this Supplemental Indenture and all other indentures supplemental to the Principal Indenture shall be read, taken and construed as one and the same instrument. Neither the execution of this Supplemental Indenture nor anything herein contained shall be construed to impair the lien of the Indenture on any of the properties subject thereto, and such lien shall remain in full force and effect as security for all bonds now outstanding or hereafter issued under the Indenture. All covenants and provisions of the Indenture shall continue in full force and effect and this Supplemental Indenture shall form part of the Indenture. 6 SECTION 2. If the date for making any payment or the last date for performance of any act or the exercising of any right, as provided in this Supplemental Indenture, shall not be a Business Day (as defined in the 1993 Mortgage), such payment may be made or act performed or right exercised on the next succeeding Business Day with the same force and effect as if done on the nominal date provided in this Supplemental Indenture. SECTION 3. The terms defined in the Indenture shall, for all purposes of this Supplemental Indenture, have the meaning specified in the Indenture except as set forth in Section 4 of this Article or otherwise set forth in this Supplemental Indenture or unless the context clearly indicates some other meaning to be intended. SECTION 4. Any term defined in Section 303 of the Trust Indenture Act of 1939, as amended, and not otherwise defined in the Indenture shall, with respect to this Supplemental Indenture, the Collateral Series N Bonds and the Collateral Series O Bonds, have the meaning assigned to such term in Section 303 as in force on the date of the execution of this Supplemental Indenture. SECTION 5. This Supplemental Indenture may be executed in any number of counterparts, and all of said counterparts executed and delivered, each as an original, shall constitute but one and the same instrument. 7 IN WITNESS WHEREOF, Public Service Company of Colorado, party hereto of the first part, has caused its corporate name to be hereunto affixed, and this instrument to be signed by its President, an Executive Vice President, a Senior Vice President or a Vice President, and its corporate seal to be hereunto affixed and attested by its Secretary or an Assistant Secretary for and in its behalf; and U.S. Bank Trust National Association, the party hereto of the second part, in evidence of its acceptance of the trust hereby created, has caused its corporate name to be hereunto affixed, and this instrument to be signed and its corporate seal to be affixed by one of its Assistant Vice Presidents and attested by one of its Trust Officers, for and in its behalf, all as of the day and year first above written. PUBLIC SERVICE COMPANY OF COLORADO By: /s/ Benjamin G. S. Fowke III ---------------------------------------- Name: Benjamin G. S. Fowke III Title: Vice President and Treasurer ATTEST: /s/ Anne M. Ziebell ------------------------------------- Name: Anne M. Ziebell Title: Assistant Secretary STATE OF MINNESOTA ) ) ss.: CITY OF MINNEAPOLIS ) On this 1st day of September, 2003, before me, Sharon M. Quellhorst, a duly authorized Notary Public in and for said City in the State aforesaid, personally appeared Benjamin G. S. Fowke III and Anne M. Ziebell to me known to be a Vice President and Treasurer and the Assistant Secretary, respectively, of PUBLIC SERVICE COMPANY OF COLORADO, a corporation organized and existing under the laws of the State of Colorado, one of the corporations that executed the within and foregoing instrument; and the said Vice President and Treasurer and Assistant Secretary severally acknowledged the said instrument to be the free and voluntary act and deed of said corporation, for the uses and purposes therein mentioned, and on oath stated that they were authorized to execute said instrument and that the seal affixed thereto is the corporate seal of said corporation. IN WITNESS WHEREOF, I have hereunto set my hand and affixed my official seal the day and year first above written. /s/ Sharon M. Quellhorst --------------------------------------- Name: Sharon M. Quellhorst Notary Public, State of Minnesota Commission Expires: January 31, 2005 8 U.S. BANK TRUST NATIONAL ASSOCIATION, as Trustee By: /s/ Ignazio Tamburello ----------------------------------------- Name: Ignazio Tamburello Title: Assistant Vice President ATTEST: /s/ Adam Berman ------------------------------- Name: Adam Berman Title: Trust Officer STATE OF NEW YORK ) ) ss.: CITY AND COUNTY OF NEW YORK ) On this 2nd day of September, 2003, before me, Rouba Fakih, a duly authorized Notary Public in and for said City and County in the State aforesaid, personally appeared Ignazio Tamburello and Adam Berman to me known to be an Assistant Vice President and a Trust Officer, respectively, of U.S. BANK TRUST NATIONAL ASSOCIATION, a national banking association, one of the corporations that executed the within and foregoing instrument; and the said Assistant Vice President and Trust Officer severally acknowledged the said instrument to be the free and voluntary act and deed of said corporation, for the uses and purposes therein mentioned, and on oath stated that they were authorized to execute said instrument and that the seal affixed thereto is the corporate seal of said corporation. IN WITNESS WHEREOF, I have hereunto set my hand and affixed my official seal the day and year first above written. /s/ Rouba Fakih ---------------------------------------------- Name: Rouba Fakih Notary Public, State of New York Commission Expires: February 20, 2007 9 EXHIBIT A FORM OF COLLATERAL SERIES N BOND THIS BOND IS NOT TRANSFERABLE EXCEPT TO A SUCCESSOR TRUSTEE UNDER THE INDENTURE, DATED AS OF OCTOBER 1, 1993, AS SUPPLEMENTED, BETWEEN PUBLIC SERVICE COMPANY OF COLORADO AND U.S. BANK TRUST NATIONAL ASSOCIATION (FORMERLY FIRST TRUST OF NEW YORK, NATIONAL ASSOCIATION), AS SUCCESSOR TRUSTEE THEREUNDER. PUBLIC SERVICE COMPANY OF COLORADO FIRST MORTGAGE BOND, Collateral Series N DUE 2008 REGISTERED REGISTERED No. _________________ $__________________ FOR VALUE RECEIVED, PUBLIC SERVICE COMPANY OF COLORADO, a corporation organized and existing under the laws of the State of Colorado (hereinafter sometimes called the "Company"), promises to pay to U.S. Bank Trust National Association (formerly known as First Trust of New York, National Association), as successor trustee (the "1993 Mortgage Trustee") under the Indenture, dated as of October 1, 1993 (the "1993 Mortgage"), of the Company, or registered assigns, Dollars on October 1, 2008, at the office or agency of the Company in the city in which the principal corporate trust office of the 1993 Mortgage Trustee is located. This bond shall not bear interest. The principal of this bond shall be payable in any coin or currency of the United States of America which at the time of payment shall be legal tender for the payment of public and private debts. Any payment by the Company under the 1993 Mortgage of the principal of securities which shall have been authenticated and delivered under the 1993 Mortgage on the basis of the issuance and delivery to the 1993 Mortgage Trustee of this bond (other than by the application of the proceeds of a payment in respect of this bond) shall, to the extent thereof, be deemed to satisfy and discharge the obligation of the Company, if any, to make a payment of principal of this bond which is then due. This bond is one of an issue of bonds of the Company, issued and to be issued in one or more series under and equally and ratably secured (except as any sinking, amortization, improvement or other fund, established in accordance with the provisions of the indenture Exhibit A-1 hereinafter mentioned, may afford additional security for the bonds of any particular series) by a certain indenture, dated as of December 1, 1939, made by the Company to U.S. BANK TRUST NATIONAL ASSOCIATION (formerly First Trust of New York, National Association), as successor trustee (hereinafter called the "Trustee") to Morgan Guaranty Trust Company of New York (formerly Guaranty Trust Company of New York), as amended and supplemented by several indentures supplemental thereto, including the Supplemental Indenture dated as of September 1, 2003 (said Indenture as amended and supplemented by said indentures supplemental thereto being hereinafter called the "Indenture"), to which Indenture reference is hereby made for a description of the property mortgaged, the nature and extent of the security, the rights and limitations of rights of the Company, the Trustee, and the holders of said bonds, under the Indenture, and the terms and conditions upon which said bonds are secured, to all of the provisions of which Indenture and of all indentures supplemental thereto in respect of such security, including the provisions of the Indenture permitting the issue of bonds of any series for property which, under the restrictions and limitations therein specified, may be subject to liens prior to the lien of the Indenture, the holder, by accepting this bond, assents. To the extent permitted by and as provided in the Indenture, the rights and obligations of the Company and of the holders of said bonds (including those pertaining to any sinking or other fund) may be changed and modified, with the consent of the Company, by the holders of at least 75% in aggregate principal amount of the bonds then outstanding (excluding bonds disqualified from voting by reason of the Company's interest therein as provided in the Indenture); provided, however, that without the consent of the holder hereof no such modification or alteration shall be made which will extend the time of payment of the principal of this bond or reduce the principal amount hereof or effect any other modification of the terms of payment of such principal or will reduce the percentage of bonds required for the aforesaid actions under the Indenture. The Company has reserved the right to amend the Indenture without any consent or other action by holders of any series of bonds created after October 31, 1975 (including this series) so as to change 75% in the foregoing sentence to 60% and to change certain procedures relating to bondholders' meetings. This bond is one of a series of bonds designated as the First Mortgage Bonds, Collateral Series N, of the Company. This bond shall be redeemable at the option of the Company in whole at any time, or in part from time to time, prior to maturity, at a redemption price equal to 100% of the principal amount thereof to be redeemed. The principal of this bond may be declared or may become due before the maturity hereof, on the conditions, in the manner and at the times set forth in the Indenture, upon the happening of an event of default as therein provided. This bond is not transferable except to a successor trustee under the 1993 Mortgage, any such transfer to be made at the office or agency of the Company in the city in which the principal corporate trust office of the 1993 Mortgage Trustee is located, upon surrender and cancellation of this bond, and thereupon a new bond of this series of a like principal amount will be issued to the transferee in exchange therefor, as provided in the Indenture. The Company, the Trustee, any paying agent and any registrar may deem and treat the person in whose name this bond is registered as the absolute owner hereof for the purpose of receiving payment and for all other purposes. This bond, alone or with other bonds of this series, may in like manner be exchanged at such office or agency for one or more new bonds of this series of the same aggregate principal Exhibit A-2 amount, all as provided in the Indenture. No service charge shall be made to any holder of any bond of this series for any exchange or transfer of bonds. No recourse under or upon any covenant or obligation of the Indenture, or of any bonds thereby secured, or for any claim based thereon, or otherwise in any manner in respect thereof, shall be had against any incorporator, subscriber to the capital stock, shareholder, officer or director, as such, of the Company, whether former, present or future, either directly, or indirectly through the Company or the Trustee, by the enforcement of any subscription to capital stock, assessment or otherwise, or by any legal or equitable proceeding by virtue of any statute or otherwise (including, without limiting the generality of the foregoing, any proceeding to enforce any claimed liability of shareholders of the Company based upon any theory of disregarding the corporate entity of the Company or upon any theory that the Company was acting as the agent or instrumentality of the shareholders), any and all such liability of incorporators, shareholders, subscribers, officers and directors, as such, being released by the holder hereof, by the acceptance of this bond, and being likewise waived and released by the terms of the Indenture under which this bond is issued. This bond shall not be valid or become obligatory for any purpose until the certificate of authentication endorsed hereon shall have been signed by U.S. Bank Trust National Association, or its successor, as Trustee under the Indenture. IN WITNESS WHEREOF, Public Service Company of Colorado has caused this bond to be signed in its name by a Vice President and its corporate seal to be affixed hereto and attested by its Secretary or an Assistant Secretary. Dated: PUBLIC SERVICE COMPANY OF COLORADO By: ______________________________ [Vice President] ATTEST:________________________ [Assistant Secretary] CERTIFICATE OF AUTHENTICATION This is one of the securities of the series designated therein referred to in the within-mentioned Supplemental Indenture. Dated: U.S. BANK TRUST NATIONAL ASSOCIATION, AS TRUSTEE By: ______________________________ Authorized Officer Exhibit A-3 EXHIBIT B FORM OF COLLATERAL SERIES O BOND THIS BOND IS NOT TRANSFERABLE EXCEPT TO A SUCCESSOR TRUSTEE UNDER THE INDENTURE, DATED AS OF OCTOBER 1, 1993, AS SUPPLEMENTED, BETWEEN PUBLIC SERVICE COMPANY OF COLORADO AND U.S. BANK TRUST NATIONAL ASSOCIATION (FORMERLY FIRST TRUST OF NEW YORK, NATIONAL ASSOCIATION), AS SUCCESSOR TRUSTEE THEREUNDER. PUBLIC SERVICE COMPANY OF COLORADO FIRST MORTGAGE BOND, Collateral Series O DUE 2014 REGISTERED REGISTERED No._______________ $______________ FOR VALUE RECEIVED, PUBLIC SERVICE COMPANY OF COLORADO, a corporation organized and existing under the laws of the State of Colorado (hereinafter sometimes called the "Company"), promises to pay to U.S. Bank Trust National Association (formerly known as First Trust of New York, National Association), as successor trustee (the "1993 Mortgage Trustee") under the Indenture, dated as of October 1, 1993 (the "1993 Mortgage"), of the Company, or registered assigns, Dollars on April 1, 2014, at the office or agency of the Company in the city in which the principal corporate trust office of the 1993 Mortgage Trustee is located. This bond shall not bear interest. The principal of this bond shall be payable in any coin or currency of the United States of America which at the time of payment shall be legal tender for the payment of public and private debts. Any payment by the Company under the 1993 Mortgage of the principal of securities which shall have been authenticated and delivered under the 1993 Mortgage on the basis of the issuance and delivery to the 1993 Mortgage Trustee of this bond (other than by the application of the proceeds of a payment in respect of this bond) shall, to the extent thereof, be deemed to satisfy and discharge the obligation of the Company, if any, to make a payment of principal of this bond which is then due. This bond is one of an issue of bonds of the Company, issued and to be issued in one or more series under and equally and ratably secured (except as any sinking, amortization, improvement or other fund, established in accordance with the provisions of the indenture Exhibit B-1 hereinafter mentioned, may afford additional security for the bonds of any particular series) by a certain indenture, dated as of December 1, 1939, made by the Company to U.S. BANK TRUST NATIONAL ASSOCIATION (formerly First Trust of New York, National Association), as successor trustee (hereinafter called the "Trustee") to Morgan Guaranty Trust Company of New York (formerly Guaranty Trust Company of New York), as amended and supplemented by several indentures supplemental thereto, including the Supplemental Indenture dated as of September 1, 2003 (said Indenture as amended and supplemented by said indentures supplemental thereto being hereinafter called the "Indenture"), to which Indenture reference is hereby made for a description of the property mortgaged, the nature and extent of the security, the rights and limitations of rights of the Company, the Trustee, and the holders of said bonds, under the Indenture, and the terms and conditions upon which said bonds are secured, to all of the provisions of which Indenture and of all indentures supplemental thereto in respect of such security, including the provisions of the Indenture permitting the issue of bonds of any series for property which, under the restrictions and limitations therein specified, may be subject to liens prior to the lien of the Indenture, the holder, by accepting this bond, assents. To the extent permitted by and as provided in the Indenture, the rights and obligations of the Company and of the holders of said bonds (including those pertaining to any sinking or other fund) may be changed and modified, with the consent of the Company, by the holders of at least 75% in aggregate principal amount of the bonds then outstanding (excluding bonds disqualified from voting by reason of the Company's interest therein as provided in the Indenture); provided, however, that without the consent of the holder hereof no such modification or alteration shall be made which will extend the time of payment of the principal of this bond or reduce the principal amount hereof or effect any other modification of the terms of payment of such principal or will reduce the percentage of bonds required for the aforesaid actions under the Indenture. The Company has reserved the right to amend the Indenture without any consent or other action by holders of any series of bonds created after October 31, 1975 (including this series) so as to change 75% in the foregoing sentence to 60% and to change certain procedures relating to bondholders' meetings. This bond is one of a series of bonds designated as the First Mortgage Bonds, Collateral Series O, of the Company. This bond shall be redeemable at the option of the Company in whole at any time, or in part from time to time, prior to maturity, at a redemption price equal to 100% of the principal amount thereof to be redeemed. The principal of this bond may be declared or may become due before the maturity hereof, on the conditions, in the manner and at the times set forth in the Indenture, upon the happening of an event of default as therein provided. This bond is not transferable except to a successor trustee under the 1993 Mortgage, any such transfer to be made at the office or agency of the Company in the city in which the principal corporate trust office of the 1993 Mortgage Trustee is located, upon surrender and cancellation of this bond, and thereupon a new bond of this series of a like principal amount will be issued to the transferee in exchange therefor, as provided in the Indenture. The Company, the Trustee, any paying agent and any registrar may deem and treat the person in whose name this bond is registered as the absolute owner hereof for the purpose of receiving payment and for all other purposes. This bond, alone or with other bonds of this series, may in like manner be exchanged at such office or agency for one or more new bonds of this series of the same aggregate principal Exhibit B-2 amount, all as provided in the Indenture. No service charge shall be made to any holder of any bond of this series for any exchange or transfer of bonds. No recourse under or upon any covenant or obligation of the Indenture, or of any bonds thereby secured, or for any claim based thereon, or otherwise in any manner in respect thereof, shall be had against any incorporator, subscriber to the capital stock, shareholder, officer or director, as such, of the Company, whether former, present or future, either directly, or indirectly through the Company or the Trustee, by the enforcement of any subscription to capital stock, assessment or otherwise, or by any legal or equitable proceeding by virtue of any statute or otherwise (including, without limiting the generality of the foregoing, any proceeding to enforce any claimed liability of shareholders of the Company based upon any theory of disregarding the corporate entity of the Company or upon any theory that the Company was acting as the agent or instrumentality of the shareholders), any and all such liability of incorporators, shareholders, subscribers, officers and directors, as such, being released by the holder hereof, by the acceptance of this bond, and being likewise waived and released by the terms of the Indenture under which this bond is issued. This bond shall not be valid or become obligatory for any purpose until the certificate of authentication endorsed hereon shall have been signed by U.S. Bank Trust National Association, or its successor, as Trustee under the Indenture. IN WITNESS WHEREOF, Public Service Company of Colorado has caused this bond to be signed in its name by a Vice President and its corporate seal to be affixed hereto and attested by its Secretary or an Assistant Secretary. Dated: PUBLIC SERVICE COMPANY OF COLORADO By: __________________________ [Vice President] ATTEST:________________________ [Assistant Secretary] CERTIFICATE OF AUTHENTICATION This is one of the securities of the series designated therein referred to in the within-mentioned Supplemental Indenture. Dated: U.S. BANK TRUST NATIONAL ASSOCIATION, AS TRUSTEE By: _________________________________ Authorized Officer Exhibit B-3 SCHEDULE A SUPPLEMENTAL INDENTURES

DATE OF PRINCIPAL SUPPLEMENTAL PRINCIPAL AMOUNT INDENTURE SERIES OF BONDS AMOUNT ISSUED OUTSTANDING --------- --------------- ------------- ----------- March 14, 1941 None -- -- May 14, 1941 None -- -- April 28, 1942 None -- -- April 14, 1943 None -- -- April 27, 1944 None -- -- April 18, 1945 None -- -- April 23, 1946 None -- -- April 9, 1947 None -- -- June 1, 1947* 2-7/8% Series due 1977 $ 40,000,000 None April 1, 1948 None -- -- May 20, 1948 None -- -- October 1, 1948 3-1/8% Series due 1978 10,000,000 None April 20, 1949 None -- -- April 24, 1950 None -- -- April 18, 1951 None -- -- October 1, 1951 3-1/4% Series due 1981 15,000,000 None April 21, 1952 None -- -- December 1, 1952 None -- -- April 15, 1953 None -- -- April 19, 1954 None -- -- October 1, 1954* 3-1/8% Series due 1984 20,000,000 None April 18, 1955 None -- -- April 24, 1956 None -- -- May 1, 1957* 4-3/8% Series due 1987 30,000,000 None April 10, 1958 None -- -- May 1, 1959 4-5/8% Series due 1989 20,000,000 None April 18, 1960 None -- -- April 19, 1961 None -- -- October 1, 1961 4-1/2% Series due 1991 30,000,000 None March 1, 1962 4-5/8% Series due 1992 8,800,000 None June 1, 1964 4-1/2% Series due 1994 35,000,000 None May 1, 1966 5-3/8% Series due 1996 35,000,000 None July 1, 1967* 5-7/8% Series due 1997 35,000,000 None July 1, 1968* 6-3/4% Series due 1998 25,000,000 None April 25, 1969 None -- --

Schedule A-1

DATE OF PRINCIPAL SUPPLEMENTAL PRINCIPAL AMOUNT INDENTURE SERIES OF BONDS AMOUNT ISSUED OUTSTANDING - ------------ --------------- ------------- ----------- April 21, 1970 None -- -- September 1, 1970 8-3/4% Series due 2000 35,000,000 None February 1, 1971 7-1/4% Series due 2001 40,000,000 None August 1, 1972 7-1/2% Series due 2002 50,000,000 None June 1, 1973 7-5/8% Series due 2003 50,000,000 None March 1, 1974 Pollution Control Series A 24,000,000 None December 1, 1974 Pollution Control Series B 50,000,000 None October 1, 1975 9-3/8% Series due 2005 50,000,000 None April 28, 1976 None -- -- April 28, 1977 None -- -- November 1, 1977* 8-1/4% Series due 2007 50,000,000 None April 28, 1978 None -- -- October 1, 1978 9-1/4% Series due 2008 50,000,000 None October 1, 1979* Pollution Control Series C 50,000,000 None March 1, 1980* 15% Series due 1987 50,000,000 None April 28, 1981 None -- -- November 1, 1981* Pollution Control Series D 27,380,000 None December 1, 1981* 16-1/4% Series due 2011 50,000,000 None April 29, 1982 None -- -- May 1, 1983* Pollution Control Series E 42,000,000 None April 30, 1984 None -- -- March 1, 1985* 13% Series due 2015 50,000,000 None November 1, 1986* Pollution Control Series F 27,250,000 None May 1, 1987* 8.95% Series due 1992 75,000,000 None July 1, 1990* 9-7/8% Series due 2020 75,000,000 None December 1, 1990* Secured Medium-Term Notes, Series A 191,500,000** None March 1, 1992* 8-1/8% Series due 2004 and 100,000,000 100,000,000 8-3/4% Series due 2022 150,000,000 None April 1, 1993* Pollution Control Series G 79,500,000 79,500,000 June 1, 1993* Pollution Control Series H 50,000,000 50,000,000 November 1, 1993* Collateral Series A 134,500,000 134,500,000 January 1, 1994* Collateral Series B due 2001 and 102,667,000 None Collateral Series B due 2024 110,000,000 110,000,000 September 2, 1994 None -- -- (Appointment of Successor Trustee) May 1, 1996 Collateral Series C 125,000,000 125,000,000

Schedule A-2

DATE OF PRINCIPAL SUPPLEMENTAL PRINCIPAL AMOUNT INDENTURE SERIES OF BONDS AMOUNT ISSUED OUTSTANDING --------- --------------- ------------- ----------- November 1, 1996 Collateral Series D 250,000,000 175,000,000 February 1, 1997 Collateral Series E 150,000,000 None April 1, 1998 Collateral Series F 250,000,000 None August 15, 2002 Collateral Series G 48,750,000 48,750,000 September 1, 2002 Collateral Series H 600,000,000 None September 15, 2002 Collateral Series I 530,000,000 None April 1, 2003 Collateral Series J 600,000,000 600,000,000 March 1, 2003 Collateral Series K 250,000,000 250,000,000 May 1, 2003 Collateral Series M 350,000,000 350,000,000

- -------------------------- * Contains amendatory provisions ** $200,000,000 authorized Schedule A-3 EX-4.02 5 c79426exv4w02.txt EX-4.02 SUPPLEMENTAL INDENTURE NO. 15 PUBLIC SERVICE COMPANY OF COLORADO TO U.S. BANK TRUST NATIONAL ASSOCIATION, AS TRUSTEE ----------------------- SUPPLEMENTAL INDENTURE NO. 15 Dated as of September 1, 2003 Supplemental to the Indenture dated as of October 1, 1993 ----------------------- Establishing the Securities of Series No. 14 and Series No. 15, designated First Collateral Trust Bonds, Series No. 14 and First Collateral Trust Bonds, Series No. 15, respectively SUPPLEMENTAL INDENTURE NO. 15, dated as of September 1, 2003, between PUBLIC SERVICE COMPANY OF COLORADO, a corporation duly organized and existing under the laws of the State of Colorado (hereinafter sometimes called the "Company"), and U.S. BANK TRUST NATIONAL ASSOCIATION (FORMERLY FIRST TRUST OF NEW YORK, NATIONAL ASSOCIATION), a national banking association, as successor trustee (hereinafter sometimes called the "Trustee") to Morgan Guaranty Trust Company of New York under the Indenture, dated as of October 1, 1993 (hereinafter called the "Original Indenture"), as previously supplemented and as further supplemented by this Supplemental Indenture No. 15. The Original Indenture and any and all indentures and all other instruments supplemental thereto are hereinafter sometimes collectively called the "Indenture". RECITALS OF THE COMPANY The Original Indenture was authorized, executed and delivered by the Company to provide for the issuance from time to time of its Securities (such term and all other capitalized terms used herein without definition having the meanings assigned to them in the Original Indenture), to be issued in one or more series as contemplated therein, and to provide security for the payment of the principal of and premium, if any, and interest, if any, on the Securities. The Company has heretofore executed and delivered to the Trustee the Supplemental Indentures referred to in Schedule A hereto for the purpose of establishing a series of bonds and appointing the successor Trustee. The Company desires to establish two new series of Securities to be designated "First Collateral Trust Bonds, Series No. 14" and "First Collateral Trust Bonds, Series No. 15", such series of Securities to be hereinafter sometimes called "Series No. 14" and "Series No. 15," respectively. The Company has duly authorized the execution and delivery of this Supplemental Indenture No. 15 to establish the Securities of Series No. 14 and Series No. 15 and has duly authorized the issuance of such Securities; and all acts necessary to make this Supplemental Indenture No. 15 a valid agreement of the Company, and to make the Securities of Series No. 14 and Series No. 15 valid obligations of the Company, have been performed. GRANTING CLAUSES NOW, THEREFORE, THIS SUPPLEMENTAL INDENTURE NO. 15 WITNESSETH, that, in consideration of the premises and of the purchase of the Securities by the Holders thereof, and in order to secure the payment of the principal of and premium, if any, and interest, if any, on all Securities from time to time Outstanding and the performance of the covenants contained therein and in the Indenture and to declare the terms and conditions on which such Securities are secured, the Company hereby grants, bargains, sells, releases, conveys, assigns, transfers, mortgages, pledges, sets over and confirms to the Trustee, and grants to the Trustee a security interest in, the following: GRANTING CLAUSE FIRST All right, title and interest of the Company, as of the date of the execution and delivery of this Supplemental Indenture No. 15, in and to property (other than Excepted Property), real, personal and mixed and wherever situated, in any case used or to be used in or in connection with the Electric Utility Business (whether or not such use is the sole use of such property), including without limitation (a) all lands, easements, servitudes, licenses, permits, rights of way and other rights and interests in or relating to real property used or to be used in or in connection with the Electric Utility Business or relating to the occupancy or use of such real property, subject however, to the exceptions and exclusions set forth in clause (a) of Granting Clause First of the Original Indenture; (b) all plants, generators, turbines, engines, boilers, fuel handling and transportation facilities, air and water pollution control and sewage and solid waste disposal facilities and other machinery and facilities for the generation of electric energy; (c) all switchyards, lines, towers, substations, transformers and other machinery and facilities for the transmission of electric energy; (d) all lines, poles, conduits, conductors, meters, regulators and other machinery and facilities for the distribution of electric energy; (e) all buildings, offices, warehouses and other structures used or to be used in or in connection with the Electric Utility Business; (f) all pipes, cables, insulators, ducts, tools, computers and other data processing and/or storage equipment and other equipment, apparatus and facilities used or to be used in or in connection with the Electric Utility Business; (g) any or all of the foregoing properties in the process of construction; and (h) all other property, of whatever kind and nature, ancillary to or otherwise used or to be used in conjunction with any or all of the foregoing or otherwise, directly or indirectly, in furtherance of the Electric Utility Business; GRANTING CLAUSE SECOND Subject to the applicable exceptions permitted by Section 810(c), Section 1303 and Section 1305 of the Original Indenture, all property (other than Excepted Property) of the kind and nature described in Granting Clause First which may be hereafter acquired by the Company, it being the intention of the Company that all such property acquired by the Company after the date of the execution and delivery of this Supplemental Indenture No. 15 shall be as fully embraced within and subjected to the Lien hereof as if such property were owned by the Company as of the date of the execution and delivery of this Supplemental Indenture No. 15; GRANTING CLAUSE FOURTH All other property of whatever kind and nature subjected or required to be subjected to the Lien of the Indenture by any of the provisions thereof; EXCEPTED PROPERTY Expressly excepting and excluding, however, from the Lien and operation of the Indenture all Excepted Property of the Company, whether now owned or hereafter acquired; TO HAVE AND TO HOLD all such property, real, personal and mixed, unto the Trustee, its successors in trust and their assigns forever; SUBJECT, HOWEVER, to (a) Liens existing at the date of the execution and delivery of the Original Indenture (including, but not limited to, the Lien of the PSCO 1939 Mortgage), (b) as to property acquired by the Company after the date of the execution and delivery of the Original Indenture, Liens existing or placed thereon at the time of the acquisition thereof (including, but not limited to, the Lien of any Class A Mortgage and purchase money Liens), (c) Retained Interests and (d) any other Permitted Liens, it being understood that, with respect to any property which was at the date of execution and delivery of the Original Indenture or thereafter became or hereafter becomes subject to the Lien of any Class A Mortgage, the Lien of the Indenture shall at all times be junior, subject and subordinate to the Lien of such Class A Mortgage; 2 IN TRUST, NEVERTHELESS, for the equal and proportionate benefit and security of the Holders from time to time of all Outstanding Securities without any priority of any such Security over any other such Security; PROVIDED, HOWEVER, that the right, title and interest of the Trustee in and to the Mortgaged Property shall cease, terminate and become void in accordance with, and subject to the conditions set forth in, Article Nine of the Original Indenture, and if, thereafter, the principal of and premium, if any, and interest, if any, on the Securities shall have been paid to the Holders thereof, or shall have been paid to the Company pursuant to Section 603 of the Original Indenture, then and in that case the Indenture shall terminate, and the Trustee shall execute and deliver to the Company such instruments as the Company shall require to evidence such termination; otherwise the Indenture, and the estate and rights thereby granted shall be and remain in full force and effect; and THE PARTIES HEREBY FURTHER COVENANT AND AGREE as follows: ARTICLE ONE SECURITIES OF SERIES NO. 14 There are hereby established the Securities of Series No. 14, which shall have the terms and characteristics set forth below (the lettered subdivisions set forth below corresponding to the lettered subdivisions of Section 301 of the Original Indenture): (a) the title of the Securities of Series No. 14 shall be "First Collateral Trust Bonds, Series No. 14"; provided, however, that, at any time after the PSCO 1939 Mortgage shall have been satisfied and discharged, the Company shall have the right, without any consent or other action by the Holders of the Securities, to change the title of the series in such manner as shall be deemed by the Company to be appropriate to reflect such satisfaction and discharge, such change to be evidenced in an Officer's Certificate; (b) the Securities of Series No. 14 shall be initially authenticated and delivered in the aggregate principal amount of $300,000,000; (c) interest on the Securities of Series No. 14 shall be payable to the Persons in whose names such Securities are registered at the close of business on the Regular Record Date for such interest, except as otherwise expressly provided in the form of such Securities attached as Exhibit A hereto; (d) the principal of the Securities of Series No. 14 shall be payable on October 1, 2008, the Stated Maturity for Series No. 14; (e) the Securities of Series No. 14 shall bear interest at a rate of 4.375% per annum; interest shall accrue on the Securities of Series No. 14 from September 9, 2003, or the most recent date to which interest has been paid or duly provided for; the Interest Payment Dates for such Securities shall be April 1 and October 1 in each year, commencing April 1, 2004, and the Regular Record Dates with respect to the Interest Payment Dates for such Securities shall be March 15 and September 15 in each year, respectively (whether or not a Business Day); 3 (f) the Corporate Trust Office of U.S. Bank Trust National Association in New York, New York shall be the place at which (i) the principal of, premium, if any, and interest, if any, on the Securities of Series No. 14 shall be payable, (ii) registration of transfer of such Securities may be effected, (iii) exchanges of such Securities may be effected and (iv) notices and demands to or upon the Company in respect of such Securities and the Indenture may be served; and U.S. Bank Trust National Association shall be the Security Registrar for such Securities; provided, however, that the Company reserves the right to change, by one or more Officer's Certificates, any such place or the Security Registrar; and provided, further, that the Company reserves the right to designate, by one or more Officer's Certificates, its principal office in Denver, Colorado as any such place or itself as the Security Registrar; (g) the Securities of Series No. 14 shall be redeemable at the option of the Company at any time prior to their Maturity, in whole or in part, at a redemption price equal to the greater of (i) 100% of the principal amount thereof to be redeemed, or (ii) the sum of the present values of the remaining scheduled payments of principal and interest on such Securities to be redeemed, discounted to the Redemption Date on a semi-annual basis (assuming a 360-day year consisting of twelve 30-day months) at the Treasury Yield plus 15 basis points, plus in each case, accrued and unpaid interest to the Redemption Date. For purposes hereof, the following defined terms shall have the meaning ascribed to them: "Treasury Yield" means, for any Redemption Date, the rate per annum equal to the semi-annual equivalent yield to maturity of the Comparable Treasury Issue, assuming a price for the Comparable Treasury Issue (expressed as a percentage of its principal amount) equal to the Comparable Treasury Price for the Redemption Date. "Comparable Treasury Issue" means the United States Treasury security selected by the Independent Investment Banker as having a maturity comparable to the remaining term of the Securities of Series No. 14 that would be utilized, at the time of selection and in accordance with customary financial practice, in pricing new issues of corporate debt securities of comparable maturity to the remaining term of the Securities of Series No. 14. "Comparable Treasury Price" means, for any Redemption Date, (i) the average of the bid and asked prices for the Comparable Treasury Issue (expressed in each case as a percentage of its principal amount) on the third Business Day preceding the Redemption Date, as set forth in the daily statistical release (or any successor release) published by the Federal Reserve Bank of New York and designated "Composite 3:30 p.m. Quotations for U.S. Government Securities" or (ii) if that release (or any successor release) is not published or does not contain those prices on that Business Day, (A) the average of the Reference Treasury Dealer Quotations for the Redemption Date, after excluding the highest and lowest Reference Treasury Dealer Quotations for the Redemption Date, or (B) if the Trustee obtains fewer than four Reference Treasury Dealer Quotations, the average of all of the Quotations. "Independent Investment Banker" means Banc One Capital Markets, Inc., or its successor or, if such firm or its successor is unwilling or unable to select the Comparable Treasury Issue, one of the remaining Reference Treasury Dealers appointed by the Trustee after consultation with the Company. "Reference Treasury Dealer" means (i) each of Banc One Capital Markets, Inc., McDonald Investments Inc. or UBS Securities LLC and any other Primary Treasury Dealer 4 designated by, and not affiliated with, Banc One Capital Markets, Inc., McDonald Investments Inc. or UBS Securities LLC and their respective successors, provided, however, that if any of the foregoing or any of its designees ceases to be a Primary Treasury Dealer, the Company will appoint another Primary Treasury Dealer as a substitute and (ii) any other Primary Treasury Dealer selected by the Company. "Primary Treasury Dealer" means any primary U.S. Government securities dealer in the United States. "Reference Treasury Dealer Quotations" means, for each Reference Treasury Dealer and any Redemption Date, the average, as determined by the Independent Investment Banker, of the bid and asked prices for the Comparable Treasury Issue (expressed in each case as a percentage of its principal amount) quoted in writing to the Independent Investment Banker by the Reference Treasury Dealer at 5:00 p.m. on the third Business Day preceding the Redemption Date. (h) not applicable; (i) not applicable; (j) not applicable; (k) not applicable; (l) not applicable; (m) not applicable; (n) not applicable; (o) not applicable; (p) not applicable; (q) the Securities of Series No. 14 are to be initially registered in the name of Cede & Co., as nominee for The Depository Trust Company (the "Depositary"). Such Securities shall not be transferable or exchangeable, nor shall any purported transfer be registered, except as follows: (i) such Securities may be transferred in whole, and appropriate registration of transfer effected, if such transfer is by such nominee to the Depositary, or by the Depositary to another nominee thereof, or by any nominee of the Depositary to any other nominee thereof, or by the Depositary or any nominee thereof to any successor securities depositary or any nominee thereof; and (ii) such Securities may be exchanged for definitive Securities registered in the respective names of the beneficial holders thereof, and thereafter shall be transferable without restriction, if: (A) the Depositary, or any successor securities depositary, shall have notified the Company and the Trustee that it is unwilling or unable to continue to act as securities depositary with respect to such Securities or the Depositary has ceased to be a clearing agency registered under the 5 Securities Exchange Act of 1934, as amended, and the Trustee shall not have been notified by the Company within ninety (90) days of the identity of a successor securities depositary with respect to such Securities; or (B) the Company shall have delivered to the Trustee a Company Order to the effect that such Securities shall be so exchangeable on and after a date specified therein; (r) not applicable; (s) no service charge shall be made for the registration of transfer or exchange of the Securities of Series No. 14; provided, however, that the Company may require payment of a sum sufficient to cover any tax or other governmental charge payable in connection with the exchange or transfer; (t) not applicable; (u) (i) If the Company shall have caused the Company's indebtedness in respect of any Securities of Series No. 14 to have been satisfied and discharged prior to the Maturity of such Securities, as provided in Section 901 of the Original Indenture, the Company shall, promptly after the date of such satisfaction and discharge, give a notice to each Person who was a Holder of any of such Securities on such date stating (A)(1) the aggregate principal amount of such Securities and (2) the aggregate amount of any money (other than amounts, if any, deposited in respect of accrued interest on such Securities) and the aggregate principal amount of, the rate or rates of interest on, and the aggregate fair market value of, any Eligible Obligations deposited pursuant to Section 901 of the Original Indenture with respect to such Securities and (B) that the Company will provide (and the Company shall promptly so provide) to such Person, or any beneficial owner of such Securities holding through such Person (upon written request to the Company sent to an address specified in such notice), such other information as such Person or beneficial owner, as the case may be, reasonably may request in order to enable it to determine the federal income tax consequences to it resulting from the satisfaction and discharge of the Company's indebtedness in respect of such Securities. Thereafter, the Company shall, within forty-five (45) days after the end of each calendar year, give to each Person who at any time during such calendar year was a Holder of such Securities a notice containing (X) such information as may be necessary to enable such Person to report its income, gain or loss for federal income tax purposes with respect to such Securities or the assets held on deposit in respect thereof during such calendar year or the portion thereof during which such Person was a Holder of such Securities, as the case may be (such information to be set forth for such calendar year as a whole and for each month during such year) and (Y) a statement to the effect that the Company will provide (and the Company shall promptly so provide) to such Person, or any beneficial owner of such Securities holding through such Person (upon written request to the Company sent to an address specified in such notice), such other information as such Person or beneficial owner, as the case may be, reasonably may request in order to enable it to determine its income, gain or loss for federal income tax purposes with respect to such Securities or such assets for such year or portion 6 thereof, as the case may be. The obligation of the Company to provide or cause to be provided information for purposes of income tax reporting by any Person as described in the first two sentences of this paragraph shall be deemed to have been satisfied to the extent that the Company has provided or caused to be provided substantially comparable information pursuant to any requirements of the Internal Revenue Code of 1986, as amended from time to time (the "Code") and United States Treasury regulations thereunder. (ii) Notwithstanding the provisions of subparagraph (i) above, the Company shall not be required to give any notice specified in such subparagraph or to otherwise furnish any of the information contemplated therein if the Company shall have delivered to the Trustee an Opinion of Counsel to the effect that the Holders of such Securities will not recognize income, gain or loss for federal income tax purposes as a result of the satisfaction and discharge of the Company's indebtedness in respect of such Securities and such Holders will be subject to federal income taxation on the same amounts and in the same manner and at the same times as if such satisfaction and discharge had not occurred. (iii) Anything in this clause (u) to the contrary notwithstanding, the Company shall not be required to give any notice specified in subparagraph (i) or to otherwise furnish the information contemplated therein or to deliver any Opinion of Counsel contemplated by subparagraph (ii) if the Company shall have caused Securities of Series No. 14 to be deemed to have been paid for purposes of the Indenture, as provided in Section 901 of the Original Indenture, but shall not have effected the satisfaction and discharge of its indebtedness in respect of such Securities pursuant to such Section. (v) The Securities of Series No. 14 shall be substantially in the form attached hereto as Exhibit A and shall have such further terms as are set forth in such form. ARTICLE TWO SECURITIES OF SERIES NO. 15 There are hereby established the Securities of Series No. 15, which shall have the terms and characteristics set forth below (the lettered subdivisions set forth below corresponding to the lettered subdivisions of Section 301 of the Original Indenture): (a) the title of the Securities of Series No. 15 shall be "First Collateral Trust Bonds, Series No. 15"; provided, however, that, at any time after the PSCO 1939 Mortgage shall have been satisfied and discharged, the Company shall have the right, without any consent or other action by the Holders of the Securities, to change the title of the series in such manner as shall be deemed by the Company to be appropriate to reflect such satisfaction and discharge, such change to be evidenced in an Officer's Certificate; (b) the Securities of Series No. 15 shall be initially authenticated and delivered in the aggregate principal amount of $275,000,000; (c) interest on the Securities of Series No. 15 shall be payable to the Persons in whose names such Securities are registered at the close of business on the Regular 7 Record Date for such interest, except as otherwise expressly provided in the form of such Securities attached as Exhibit B hereto; (d) the principal of the Securities of Series No. 15 shall be payable on April 1, 2014, the Stated Maturity for Series No. 15; (e) the Securities of Series No. 15 shall bear interest at a rate of 5.50% per annum; interest shall accrue on the Securities of Series No. 15 from September 9, 2003, or the most recent date to which interest has been paid or duly provided for; the Interest Payment Dates for such Securities shall be April 1 and October 1 in each year, commencing April 1, 2004, and the Regular Record Dates with respect to the Interest Payment Dates for such Securities shall be March 15 and September 15 in each year, respectively (whether or not a Business Day); (f) the Corporate Trust Office of U.S. Bank Trust National Association in New York, New York shall be the place at which (i) the principal of, premium, if any, and interest, if any, on the Securities of Series No. 15 shall be payable, (ii) registration of transfer of such Securities may be effected, (iii) exchanges of such Securities may be effected and (iv) notices and demands to or upon the Company in respect of such Securities and the Indenture may be served; and U.S. Bank Trust National Association shall be the Security Registrar for such Securities; provided, however, that the Company reserves the right to change, by one or more Officer's Certificates, any such place or the Security Registrar; and provided, further, that the Company reserves the right to designate, by one or more Officer's Certificates, its principal office in Denver, Colorado as any such place or itself as the Security Registrar; (g) the Securities of Series No. 15 shall be redeemable at the option of the Company at any time prior to their Maturity, in whole or in part, at a redemption price equal to the greater of (i) 100% of the principal amount thereof to be redeemed, or (ii) the sum of the present values of the remaining scheduled payments of principal and interest on such Securities to be redeemed, discounted to the Redemption Date on a semi-annual basis (assuming a 360-day year consisting of twelve 30-day months) at the Treasury Yield plus 20 basis points, plus in each case, accrued and unpaid interest to the Redemption Date. For purposes hereof, the following defined terms shall have the meaning ascribed to them: "Treasury Yield" means, for any Redemption Date, the rate per annum equal to the semi-annual equivalent yield to maturity of the Comparable Treasury Issue, assuming a price for the Comparable Treasury Issue (expressed as a percentage of its principal amount) equal to the Comparable Treasury Price for the Redemption Date. "Comparable Treasury Issue" means the United States Treasury security selected by the Independent Investment Banker as having a maturity comparable to the remaining term of the Securities of Series No. 15 that would be utilized, at the time of selection and in accordance with customary financial practice, in pricing new issues of corporate debt securities of comparable maturity to the remaining term of the Securities of Series No. 15. "Comparable Treasury Price" means, for any Redemption Date, (i) the average of the bid and asked prices for the Comparable Treasury Issue (expressed in each case as a percentage of its principal amount) on the third Business Day preceding the Redemption Date, as set forth in the daily statistical release (or any successor release) published by the Federal Reserve Bank of New 8 York and designated "Composite 3:30 p.m. Quotations for U.S. Government Securities" or (ii) if that release (or any successor release) is not published or does not contain those prices on that Business Day, (A) the average of the Reference Treasury Dealer Quotations for the Redemption Date, after excluding the highest and lowest Reference Treasury Dealer Quotations for the Redemption Date, or (B) if the Trustee obtains fewer than four Reference Treasury Dealer Quotations, the average of all of the Quotations. "Independent Investment Banker" means Banc One Capital Markets, Inc., or its successor or, if such firm or its successor is unwilling or unable to select the Comparable Treasury Issue, one of the remaining Reference Treasury Dealers appointed by the Trustee after consultation with the Company. "Reference Treasury Dealer" means (i) each of Banc One Capital Markets, Inc., McDonald Investments Inc. or UBS Securities LLC and any other Primary Treasury Dealer designated by, and not affiliated with, Banc One Capital Markets, Inc., McDonald Investments Inc. or UBS Securities LLC and their respective successors, provided, however, that if any of the foregoing or any of its designees ceases to be a Primary Treasury Dealer, the Company will appoint another Primary Treasury Dealer as a substitute and (ii) any other Primary Treasury Dealer selected by the Company. "Primary Treasury Dealer" means any primary U.S. Government securities dealer in the United States. "Reference Treasury Dealer Quotations" means, for each Reference Treasury Dealer and any Redemption Date, the average, as determined by the Independent Investment Banker, of the bid and asked prices for the Comparable Treasury Issue (expressed in each case as a percentage of its principal amount) quoted in writing to the Independent Investment Banker by the Reference Treasury Dealer at 5:00 p.m. on the third Business Day preceding the Redemption Date. (h) not applicable; (i) not applicable; (j) not applicable; (k) not applicable; (l) not applicable; (m) not applicable; (n) not applicable; (o) not applicable; (p) not applicable; (q) the Securities of Series No. 15 are to be initially registered in the name of Cede & Co., as nominee for The Depository Trust Company (the "Depositary"). Such Securities shall not be transferable or exchangeable, nor shall any purported transfer be registered, except as follows: 9 (i) such Securities may be transferred in whole, and appropriate registration of transfer effected, if such transfer is by such nominee to the Depositary, or by the Depositary to another nominee thereof, or by any nominee of the Depositary to any other nominee thereof, or by the Depositary or any nominee thereof to any successor securities depositary or any nominee thereof; and (ii) such Securities may be exchanged for definitive Securities registered in the respective names of the beneficial holders thereof, and thereafter shall be transferable without restriction, if: (A) the Depositary, or any successor securities depositary, shall have notified the Company and the Trustee that it is unwilling or unable to continue to act as securities depositary with respect to such Securities or the Depositary has ceased to be a clearing agency registered under the Securities Exchange Act of 1934, as amended, and the Trustee shall not have been notified by the Company within ninety (90) days of the identity of a successor securities depositary with respect to such Securities; or (B) the Company shall have delivered to the Trustee a Company Order to the effect that such Securities shall be so exchangeable on and after a date specified therein; (r) not applicable; (s) no service charge shall be made for the registration of transfer or exchange of the Securities of Series No. 15; provided, however, that the Company may require payment of a sum sufficient to cover any tax or other governmental charge payable in connection with the exchange or transfer; (t) not applicable; (u) (i) If the Company shall have caused the Company's indebtedness in respect of any Securities of Series No. 15 to have been satisfied and discharged prior to the Maturity of such Securities, as provided in Section 901 of the Original Indenture, the Company shall, promptly after the date of such satisfaction and discharge, give a notice to each Person who was a Holder of any of such Securities on such date stating (A)(1) the aggregate principal amount of such Securities and (2) the aggregate amount of any money (other than amounts, if any, deposited in respect of accrued interest on such Securities) and the aggregate principal amount of, the rate or rates of interest on, and the aggregate fair market value of, any Eligible Obligations deposited pursuant to Section 901 of the Original Indenture with respect to such Securities and (B) that the Company will provide (and the Company shall promptly so provide) to such Person, or any beneficial owner of such Securities holding through such Person (upon written request to the Company sent to an address specified in such notice), such other information as such Person or beneficial owner, as the case may be, reasonably may request in order to enable it to determine the federal income tax consequences to it resulting from the satisfaction and discharge of the Company's indebtedness in respect of such Securities. Thereafter, the Company shall, within forty-five (45) days after the end of each calendar year, give to each 10 Person who at any time during such calendar year was a Holder of such Securities a notice containing (X) such information as may be necessary to enable such Person to report its income, gain or loss for federal income tax purposes with respect to such Securities or the assets held on deposit in respect thereof during such calendar year or the portion thereof during which such Person was a Holder of such Securities, as the case may be (such information to be set forth for such calendar year as a whole and for each month during such year) and (Y) a statement to the effect that the Company will provide (and the Company shall promptly so provide) to such Person, or any beneficial owner of such Securities holding through such Person (upon written request to the Company sent to an address specified in such notice), such other information as such Person or beneficial owner, as the case may be, reasonably may request in order to enable it to determine its income, gain or loss for federal income tax purposes with respect to such Securities or such assets for such year or portion thereof, as the case may be. The obligation of the Company to provide or cause to be provided information for purposes of income tax reporting by any Person as described in the first two sentences of this paragraph shall be deemed to have been satisfied to the extent that the Company has provided or caused to be provided substantially comparable information pursuant to any requirements of the Internal Revenue Code of 1986, as amended from time to time (the "Code") and United States Treasury regulations thereunder. (i) Notwithstanding the provisions of subparagraph (i) above, the Company shall not be required to give any notice specified in such subparagraph or to otherwise furnish any of the information contemplated therein if the Company shall have delivered to the Trustee an Opinion of Counsel to the effect that the Holders of such Securities will not recognize income, gain or loss for federal income tax purposes as a result of the satisfaction and discharge of the Company's indebtedness in respect of such Securities and such Holders will be subject to federal income taxation on the same amounts and in the same manner and at the same times as if such satisfaction and discharge had not occurred. (ii) Anything in this clause (u) to the contrary notwithstanding, the Company shall not be required to give any notice specified in subparagraph (i) or to otherwise furnish the information contemplated therein or to deliver any Opinion of Counsel contemplated by subparagraph (ii) if the Company shall have caused Securities of Series No. 15 to be deemed to have been paid for purposes of the Indenture, as provided in Section 901 of the Original Indenture, but shall not have effected the satisfaction and discharge of its indebtedness in respect of such Securities pursuant to such Section. (v) The Securities of Series No. 15 shall be substantially in the form attached hereto as Exhibit B and shall have such further terms as are set forth in such form. 11 ARTICLE THREE MISCELLANEOUS PROVISIONS This Supplemental Indenture No. 15 is a supplement to the Original Indenture. As previously supplemented and further supplemented by this Supplemental Indenture No. 15, the Original Indenture is in all respects ratified, approved and confirmed, and the Original Indenture, all previous supplements thereto and this Supplemental Indenture No. 15 shall together constitute one and the same instrument. 12 IN WITNESS WHEREOF, the parties hereto have caused this Supplemental Indenture No. 15 to be duly executed as of the day and year first above written. PUBLIC SERVICE COMPANY OF COLORADO By: /s/ Benjamin G. S. Fowke III -------------------------------------- Name: Benjamin G. S. Fowke III Title: Vice President and Treasurer STATE OF MINNESOTA ) ) ss.: CITY OF MINNEAPOLIS ) On the 1st day of September, 2003, before me personally came Benjamin G. S. Fowke III to me known, who, being by me duly sworn, did depose and say that he is a Vice President and Treasurer of Public Service Company of Colorado, one of the corporations described in and which executed the foregoing instrument; and that he signed his name thereto by authority of the Board of Directors of said corporation. /s/ Sharon M. Quellhorst ------------------------------------------ Name: Sharon M. Quellhorst Notary Public, State of Minnesota Commission Expires: January 31, 2005 13 U.S. BANK TRUST NATIONAL ASSOCIATION, Trustee By: /s/ Ignazio Tamburello -------------------------------------- Name: Ignazio Tamburello Title: Assistant Vice President STATE OF NEW YORK ) ) ss.: CITY AND COUNTY OF NEW YORK ) On the 2nd day of September, 2003, before me personally came Ignazio Tamburello, to me known, who, being by me duly sworn, did depose and say that he is an Assistant Vice President of U.S. Bank Trust National Association, the banking association described in and which executed the foregoing instrument; and that he signed his name thereto by authority of the Board of Directors of said banking association. /s/ Rouba Fakih ------------------------------------------ Name: Rouba Fakih Notary Public, State of New York Commission Expires: February 20, 2007 14 EXHIBIT A FORM OF SECURITY (See legend at the end of this Security for restrictions on transfer) PUBLIC SERVICE COMPANY OF COLORADO First Collateral Trust Bond, Series No. 14 Original Interest Accrual Date September 9, 2003 Interest Rate: 4.375% Stated Maturity: October 1, 2008 Interest Payment Dates: April 1 and October 1 Regular Record Dates: March 15 and September 15 This Security is not a Discount Security within the meaning of the within-mentioned Indenture Principal Amount Registered No. $ CUSIP 744448 BW 0 PUBLIC SERVICE COMPANY OF COLORADO, a corporation duly organized and existing under the laws of the State of Colorado (herein called the "Company," which term includes any successor corporation under the Indenture referred to below), for value received, hereby promises to pay to , or registered assigns, the principal sum of Dollars on the Stated Maturity specified above, and to pay interest thereon from the Original Interest Accrual Date specified above or from the most recent Interest Payment Date to which interest has been paid or duly provided for, semi-annually in arrears on the Interest Payment Dates specified above in each year, commencing April 1, 2004, and at Maturity, at the Interest Rate per annum specified above, until the principal hereof is paid or duly provided for. The interest so payable, and paid or duly provided for, on any Interest Payment Date shall, as provided in such Indenture, be paid to the Person in whose name this Security (or one or more Predecessor Securities) is registered at the close of business on the Regular Record Date specified above (whether or not a Business Day) next preceding such Interest Payment Date. Notwithstanding the foregoing, interest payable at Maturity shall be paid to the Person to whom principal shall be paid. Except as otherwise provided in said Indenture, any such interest not so paid or duly provided for shall forthwith cease to be payable to the Holder on such Regular Record Date and may either be paid to the Person in whose name this Security (or one or more Predecessor Securities) is registered at the close of business on a Special Record Date for the payment of such Defaulted Interest to be fixed by the Trustee, notice of which shall be given to Holders of Securities of this series not less than 15 days prior to such Special Record Date, or be paid in such other manner as permitted by the Indenture. EXHIBIT A-1 Payment of the principal of this Security and interest hereon at Maturity shall be made upon presentation of this Security at the Corporate Trust Office of U.S. Bank Trust National Association, in New York, New York or at such other office or agency as may be designated for such purpose by the Company from time to time. Payment of interest on this Security (other than interest at Maturity) shall be made by check mailed to the address of the Person entitled thereto as such address shall appear in the Security Register, except that if such Person shall be a securities depositary, such payment may be made by such other means in lieu of check as shall be agreed upon by the Company, the Trustee and such Person. Payment of the principal of and interest on this Security, as aforesaid, shall be made in such coin or currency of the United States of America as at the time of payment shall be legal tender for the payment of public and private debts. This Security is one of a duly authorized issue of securities of the Company (herein called the "Securities"), issued and issuable in one or more series under and equally secured by an Indenture, dated as of October 1, 1993 (such Indenture as originally executed and delivered and as supplemented or amended from time to time thereafter, together with any constituent instruments establishing the terms of particular Securities, being herein called the "Indenture"), between the Company and U.S. Bank Trust National Association (formerly First Trust of New York, National Association) as successor trustee (herein called the "Trustee," which term includes any successor trustee under the Indenture), to which Indenture and all indentures supplemental thereto reference is hereby made for a description of the property mortgaged, pledged and held in trust, the nature and extent of the security and the respective rights, limitations of rights, duties and immunities of the Company, the Trustee and the Holders of the Securities thereunder and of the terms and conditions upon which the Securities are, and are to be, authenticated and delivered and secured. The acceptance of this Security shall be deemed to constitute the consent and agreement by the Holder hereof to all of the terms and provisions of the Indenture. This Security is one of the series designated above. If any Interest Payment Date or the Stated Maturity shall not be a Business Day (as hereinafter defined), payment of the amounts due on this Security on such date may be made on the next succeeding Business Day; and, if such payment is made or duly provided for on such Business Day, no interest shall accrue on such amounts for the period from and after such Interest Payment Date or Stated Maturity, as the case may be, to such Business Day. This Security shall be redeemable at the option of the Company at any time prior to Maturity, in whole or in part, at a redemption price equal to the greater of (i) 100% of the principal amount hereof to be redeemed, or (ii) the sum of the present values of the remaining scheduled payments of principal and interest on this Security to be redeemed, discounted to the Redemption Date on a semi-annual basis (assuming a 360-day year consisting of twelve 30-day months) at the Treasury Yield plus 15 basis points, plus in each case, accrued and unpaid interest to the Redemption Date. For purposes hereof, the following defined terms shall have the meaning ascribed to them: "Treasury Yield" means, for any Redemption Date, the rate per annum equal to the semi-annual equivalent yield to maturity of the Comparable Treasury Issue, assuming a price for the Comparable Treasury Issue (expressed as a percentage of its principal amount) equal to the Comparable Treasury Price for the Redemption Date. "Comparable Treasury Issue" means the United States Treasury security selected by the Independent Investment Banker as having a maturity comparable to the remaining term of the Securities of Series No. 14 that would be utilized, at the time of selection and in accordance with customary financial practice, in pricing new issues of corporate debt securities of comparable maturity to the remaining term of the Securities of Series No. 14. EXHIBIT A-2 "Comparable Treasury Price" means, for any Redemption Date, (i) the average of the bid and asked prices for the Comparable Treasury Issue (expressed in each case as a percentage of its principal amount) on the third Business Day preceding the Redemption Date, as set forth in the daily statistical release (or any successor release) published by the Federal Reserve Bank of New York and designated "Composite 3:30 p.m. Quotations for U.S. Government Securities" or (ii) if that release (or any successor release) is not published or does not contain those prices on that Business Day, (A) the average of the Reference Treasury Dealer Quotations for the Redemption Date, after excluding the highest and lowest Reference Treasury Dealer Quotations for the Redemption Date, or (B) if the Trustee obtains fewer than four Reference Treasury Dealer Quotations, the average of all of the Quotations. "Independent Investment Banker" means Banc One Capital Markets, Inc. or its successor or, if such firm or its successor is unwilling or unable to select the Comparable Treasury Issue, one of the remaining Reference Treasury Dealers appointed by the Trustee after consultation with the Company. "Reference Treasury Dealer" means (i) each of Banc One Capital Markets, Inc., McDonald Investments Inc. or UBS Securities LLC and any other Primary Treasury Dealer designated by, and not affiliated with, Banc One Capital Markets, Inc., McDonald Investments Inc. or UBS Securities LLC and their respective successors, provided, however, that if any of the foregoing or any of its designees ceases to be a Primary Treasury Dealer, the Company will appoint another Primary Treasury Dealer as a substitute and (ii) any other Primary Treasury Dealer selected by the Company. "Primary Treasury Dealer" means any primary U.S. Government securities dealer in the United States. "Reference Treasury Dealer Quotations" means, for each Reference Treasury Dealer and any Redemption Date, the average, as determined by the Independent Investment Banker, of the bid and asked prices for the Comparable Treasury Issue (expressed in each case as a percentage of its principal amount) quoted in writing to the Independent Investment Banker by the Reference Treasury Dealer at 5:00 p.m. on the third Business Day preceding the Redemption Date. If an Event of Default shall occur and be continuing, the principal of this Security may be declared due and payable in the manner and with the effect provided in the Indenture. The Indenture permits, with certain exceptions as therein provided, the Trustee to enter into one or more supplemental indentures for the purpose of adding any provisions to, or changing in any manner or eliminating any of the provisions of, the Indenture with the consent of the Holders of not less than a majority in aggregate principal amount of the Securities of all series then Outstanding under the Indenture, considered as one class; provided, however, that if there shall be Securities of more than one series Outstanding under the Indenture and if a proposed supplemental indenture shall directly affect the rights of the Holders of Securities of one or more, but less than all, of such series, then the consent only of the Holders of a majority in aggregate principal amount of the Outstanding Securities of all series so directly affected, considered as one class, shall be required; and provided, further, that if the Securities of any series shall have been issued in more than one Tranche and if the proposed supplemental indenture shall directly affect the rights of the Holders of Securities of one or more, but less than all, of such Tranches, then the consent only of the Holders of a majority in aggregate principal amount of the Outstanding Securities of all Tranches so directly affected, considered as one class, shall be required; and provided, further, that the Indenture permits the Trustee to enter into one or more supplemental indentures for limited purposes without the consent of any Holders of Securities. The Indenture also contains provisions permitting the Holders of a majority in principal amount of the Securities then Outstanding, on behalf of the Holders of all Securities, to waive compliance by the Company with certain provisions of the Indenture and certain past defaults under the Indenture and their consequences. Any such consent or EXHIBIT A-3 waiver by the Holder of this Security shall be conclusive and binding upon such Holder and upon all future Holders of this Security and of any Security issued upon the registration of transfer hereof or in exchange therefor or in lieu hereof, whether or not notation of such consent or waiver is made upon this Security. As provided in the Indenture and subject to certain limitations therein set forth, this Security or any portion of the principal amount hereof will be deemed to have been paid for all purposes of the Indenture and to be no longer Outstanding thereunder, and, at the election of the Company, the Company's entire indebtedness in respect thereof will be satisfied and discharged, if there has been irrevocably deposited with the Trustee or any Paying Agent (other than the Company), in trust, money in an amount which will be sufficient and/or Eligible Obligations, the principal of and interest on which when due, without regard to any reinvestment thereof, will provide moneys which, together with moneys so deposited, will be sufficient, to pay when due the principal of and interest on this Security when due. As provided in the Indenture and subject to certain limitations therein set forth, the transfer of this Security is registrable in the Security Register, upon surrender of this Security for registration of transfer at the office of U.S. Bank Trust National Association, in New York, New York or such other office or agency as may be designated by the Company from time to time, duly endorsed by, or accompanied by a written instrument of transfer in form satisfactory to the Company and the Security Registrar duly executed by, the Holder hereof or his attorney duly authorized in writing, and thereupon one or more new Securities of this series of authorized denominations and of like tenor and aggregate principal amount, will be issued to the designated transferee or transferees. The Securities of this series are issuable only as registered Securities, without coupons, and in denominations of $1,000 and integral multiples thereof. As provided in the Indenture and subject to certain limitations therein set forth, Securities of this series are exchangeable for a like aggregate principal amount of Securities of the same series, of any authorized denominations, as requested by the Holder surrendering the same, and of like tenor upon surrender of the Security or Securities to be exchanged at the office of U.S. Bank Trust National Association, in New York, New York or such other office or agency as may be designated by the Company from time to time. No service charge shall be made for any such registration of transfer or exchange, but the Company may require payment of a sum sufficient to cover any tax or other governmental charge payable in connection therewith. Prior to due presentment of this Security for registration of transfer, the Company, the Trustee and any agent of the Company or the Trustee may treat the Person in whose name this Security is registered as the absolute owner hereof for all purposes, whether or not this Security be overdue, and neither the Company, the Trustee nor any such agent shall be affected by notice to the contrary. The Indenture and the Securities shall be governed by and construed in accordance with the laws of the State of New York. As used herein "Business Day" means any day, other than a Saturday or Sunday, which is not a day on which banking institutions or trust companies in The City of New York, New York or other city in which is located any office or agency maintained for the payment of principal or interest on this Security, are authorized or required by law, regulation or executive order to remain closed. All other terms used in this Security which are defined in the Indenture shall have the meanings assigned to them in the Indenture. EXHIBIT A-4 As provided in the Indenture, no recourse shall be had for the payment of the principal of or interest on any Securities, or any part thereof, or for any claim based thereon or otherwise in respect thereof, or of the indebtedness represented thereby, or upon any obligation, covenant or agreement under the Indenture, against, and no personal liability whatsoever shall attach to, or be incurred by, any incorporator, shareholder, officer or director, as such, past, present or future of the Company or of any predecessor or successor corporation (either directly or through the Company or a predecessor or successor corporation), whether by virtue of any constitutional provision, statute or rule of law, or by the enforcement of any assessment or penalty or otherwise; it being expressly agreed and understood that the Indenture and all the Securities are solely corporate obligations and that any such personal liability is hereby expressly waived and released as a condition of, and as part of the consideration for, the execution of the Indenture and the issuance of the Securities. Unless the certificate of authentication hereon has been executed by the Trustee or an Authenticating Agent by manual signature, this Security shall not be entitled to any benefit under the Indenture or be valid or obligatory for any purpose. EXHIBIT A-5 IN WITNESS WHEREOF, the Company has caused this instrument to be duly executed and its corporate seal to be hereunto affixed and attested. PUBLIC SERVICE COMPANY OF COLORADO By: ______________________________________ [Title] Attest: ______________________________ [Title] CERTIFICATE OF AUTHENTICATION This is one of the Securities of the series designated therein referred to in the within-mentioned Indenture. Dated: _______________________________ U.S. BANK TRUST OR U.S. BANK TRUST NATIONAL ASSOCIATION, NATIONAL ASSOCIATION, as Trustee as Trustee By:_____________________________ By:___________________________ Authorized Officer AS AUTHENTICATING AGENT By:___________________________ Authorized Officer UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), TO THE COMPANY OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE, OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR IN SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE TO CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE, OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN. THIS SECURITY MAY NOT BE TRANSFERRED OR EXCHANGED, NOR MAY ANY PURPORTED TRANSFER BE REGISTERED, EXCEPT (i) THIS SECURITY MAY BE TRANSFERRED IN WHOLE, AND APPROPRIATE REGISTRATION OF TRANSFER EFFECTED, IF SUCH TRANSFER IS BY CEDE & CO., AS NOMINEE FOR THE DEPOSITORY TRUST COMPANY (THE "DEPOSITARY"), TO THE DEPOSITARY, OR BY THE DEPOSITARY TO ANOTHER NOMINEE THEREOF, OR BY ANY NOMINEE OF THE DEPOSITARY TO ANY OTHER NOMINEE THEREOF, OR BY THE DEPOSITARY OR ANY NOMINEE THEREOF TO ANY SUCCESSOR SECURITIES DEPOSITARY OR ANY NOMINEE THEREOF; AND (ii) THIS SECURITY MAY BE EXCHANGED FOR DEFINITIVE SECURITIES REGISTERED IN THE RESPECTIVE NAMES OF THE BENEFICIAL HOLDERS HEREOF, AND THEREAFTER SHALL BE TRANSFERABLE WITHOUT RESTRICTIONS IF: (A) THE DEPOSITARY, OR ANY SUCCESSOR SECURITIES DEPOSITARY, SHALL HAVE NOTIFIED THE COMPANY AND THE TRUSTEE THAT IT IS UNWILLING OR UNABLE TO CONTINUE TO ACT AS SECURITIES DEPOSITARY WITH RESPECT TO THE SECURITIES AND THE TRUSTEE SHALL NOT HAVE BEEN NOTIFIED BY THE COMPANY WITHIN NINETY (90) DAYS OF THE IDENTITY OF A SUCCESSOR EXHIBIT A-6 SECURITIES DEPOSITARY WITH RESPECT TO THE SECURITIES; OR (B) THE COMPANY SHALL HAVE DELIVERED TO THE TRUSTEE A COMPANY ORDER TO THE EFFECT THAT THE SECURITIES SHALL BE SO EXCHANGEABLE ON AND AFTER A DATE SPECIFIED THEREIN. EXHIBIT A-7 FOR VALUE RECEIVED the undersigned hereby sells, assigns and transfers unto ________________________________________________________________________________ [please insert social security or other identifying number of assignee] ________________________________________________________________________________ [please print or typewrite name and address of assignee] ________________________________________________________________________________ the within Security of PUBLIC SERVICE COMPANY OF COLORADO and does hereby irrevocably constitute and appoint __________________________________ , Attorney, to transfer said Security on the books of the within-mentioned Company, with full power of substitution in the premises. Dated:____________________________ ___________________________________________ Notice: The signature to this assignment must correspond with the name as written upon the face of the Security in every particular without alteration or enlargement or any change whatsoever. EXHIBIT A-8 EXHIBIT B FORM OF SECURITY (See legend at the end of this Security for restrictions on transfer) PUBLIC SERVICE COMPANY OF COLORADO First Collateral Trust Bond, Series No. 15 Original Interest Accrual Date September 9, 2003 Interest Rate: 5.50% Stated Maturity: April 1, 2014 Interest Payment Dates: April 1 and October 1 Regular Record Dates: March 15 and September 15 This Security is not a Discount Security within the meaning of the within-mentioned Indenture ----------------------------------------- Principal Amount Registered No. $ CUSIP 744448 BX 8 PUBLIC SERVICE COMPANY OF COLORADO, a corporation duly organized and existing under the laws of the State of Colorado (herein called the "Company," which term includes any successor corporation under the Indenture referred to below), for value received, hereby promises to pay to , or registered assigns, the principal sum of Dollars on the Stated Maturity specified above, and to pay interest thereon from the Original Interest Accrual Date specified above or from the most recent Interest Payment Date to which interest has been paid or duly provided for, semi-annually in arrears on the Interest Payment Dates specified above in each year, commencing April 1, 2004, and at Maturity, at the Interest Rate per annum specified above, until the principal hereof is paid or duly provided for. The interest so payable, and paid or duly provided for, on any Interest Payment Date shall, as provided in such Indenture, be paid to the Person in whose name this Security (or one or more Predecessor Securities) is registered at the close of business on the Regular Record Date specified above (whether or not a Business Day) next preceding such Interest Payment Date. Notwithstanding the foregoing, interest payable at Maturity shall be paid to the Person to whom principal shall be paid. Except as otherwise provided in said Indenture, any such interest not so paid or duly provided for shall forthwith cease to be payable to the Holder on such Regular Record Date and may either be paid to the Person in whose name this Security (or one or more Predecessor Securities) is registered at the close of business on a Special Record Date for the payment of such Defaulted Interest to EXHIBIT B-1 be fixed by the Trustee, notice of which shall be given to Holders of Securities of this series not less than 15 days prior to such Special Record Date, or be paid in such other manner as permitted by the Indenture. Payment of the principal of this Security and interest hereon at Maturity shall be made upon presentation of this Security at the Corporate Trust Office of U.S. Bank Trust National Association, in New York, New York or at such other office or agency as may be designated for such purpose by the Company from time to time. Payment of interest on this Security (other than interest at Maturity) shall be made by check mailed to the address of the Person entitled thereto as such address shall appear in the Security Register, except that if such Person shall be a securities depositary, such payment may be made by such other means in lieu of check as shall be agreed upon by the Company, the Trustee and such Person. Payment of the principal of and interest on this Security, as aforesaid, shall be made in such coin or currency of the United States of America as at the time of payment shall be legal tender for the payment of public and private debts. This Security is one of a duly authorized issue of securities of the Company (herein called the "Securities"), issued and issuable in one or more series under and equally secured by an Indenture, dated as of October 1, 1993 (such Indenture as originally executed and delivered and as supplemented or amended from time to time thereafter, together with any constituent instruments establishing the terms of particular Securities, being herein called the "Indenture"), between the Company and U.S. Bank Trust National Association (formerly First Trust of New York, National Association) as successor trustee (herein called the "Trustee," which term includes any successor trustee under the Indenture), to which Indenture and all indentures supplemental thereto reference is hereby made for a description of the property mortgaged, pledged and held in trust, the nature and extent of the security and the respective rights, limitations of rights, duties and immunities of the Company, the Trustee and the Holders of the Securities thereunder and of the terms and conditions upon which the Securities are, and are to be, authenticated and delivered and secured. The acceptance of this Security shall be deemed to constitute the consent and agreement by the Holder hereof to all of the terms and provisions of the Indenture. This Security is one of the series designated above. If any Interest Payment Date or the Stated Maturity shall not be a Business Day (as hereinafter defined), payment of the amounts due on this Security on such date may be made on the next succeeding Business Day; and, if such payment is made or duly provided for on such Business Day, no interest shall accrue on such amounts for the period from and after such Interest Payment Date or Stated Maturity, as the case may be, to such Business Day. This Security shall be redeemable at the option of the Company at any time prior to Maturity, in whole or in part, at a redemption price equal to the greater of (i) 100% of the principal amount hereof to be redeemed, or (ii) the sum of the present values of the remaining scheduled payments of principal and interest on this Security to be redeemed, discounted to the Redemption Date on a semi-annual basis (assuming a 360-day year consisting of twelve 30-day months) at the Treasury Yield plus 20 basis points, plus in each case, accrued and unpaid interest to the Redemption Date. For purposes hereof, the following defined terms shall have the meaning ascribed to them: "Treasury Yield" means, for any Redemption Date, the rate per annum equal to the semi-annual equivalent yield to maturity of the Comparable Treasury Issue, assuming a price for the Comparable Treasury Issue (expressed as a percentage of its principal amount) equal to the Comparable Treasury Price for the Redemption Date. "Comparable Treasury Issue" means the United States Treasury security selected by the Independent Investment Banker as having a maturity comparable to the remaining term of the Securities of Series No. 15 that would be utilized, at the time of selection and in accordance with customary EXHIBIT B-2 financial practice, in pricing new issues of corporate debt securities of comparable maturity to the remaining term of the Securities of Series No. 15. "Comparable Treasury Price" means, for any Redemption Date, (i) the average of the bid and asked prices for the Comparable Treasury Issue (expressed in each case as a percentage of its principal amount) on the third Business Day preceding the Redemption Date, as set forth in the daily statistical release (or any successor release) published by the Federal Reserve Bank of New York and designated "Composite 3:30 p.m. Quotations for U.S. Government Securities" or (ii) if that release (or any successor release) is not published or does not contain those prices on that Business Day, (A) the average of the Reference Treasury Dealer Quotations for the Redemption Date, after excluding the highest and lowest Reference Treasury Dealer Quotations for the Redemption Date, or (B) if the Trustee obtains fewer than four Reference Treasury Dealer Quotations, the average of all of the Quotations. "Independent Investment Banker" means Banc One Capital Markets, Inc. or its successor or, if such firm or its successor is unwilling or unable to select the Comparable Treasury Issue, one of the remaining Reference Treasury Dealers appointed by the Trustee after consultation with the Company. "Reference Treasury Dealer" means (i) each of Banc One Capital Markets, Inc., McDonald Investments Inc. or UBS Securities LLC and any other Primary Treasury Dealer designated by, and not affiliated with, Banc One Capital Markets, Inc., McDonald Investments Inc. or UBS Securities LLC and their respective successors, provided, however, that if any of the foregoing or any of its designees ceases to be a Primary Treasury Dealer, the Company will appoint another Primary Treasury Dealer as a substitute and (ii) any other Primary Treasury Dealer selected by the Company. "Primary Treasury Dealer" means any primary U.S. Government securities dealer in the United States. "Reference Treasury Dealer Quotations" means, for each Reference Treasury Dealer and any Redemption Date, the average, as determined by the Independent Investment Banker, of the bid and asked prices for the Comparable Treasury Issue (expressed in each case as a percentage of its principal amount) quoted in writing to the Independent Investment Banker by the Reference Treasury Dealer at 5:00 p.m. on the third Business Day preceding the Redemption Date. If an Event of Default shall occur and be continuing, the principal of this Security may be declared due and payable in the manner and with the effect provided in the Indenture. The Indenture permits, with certain exceptions as therein provided, the Trustee to enter into one or more supplemental indentures for the purpose of adding any provisions to, or changing in any manner or eliminating any of the provisions of, the Indenture with the consent of the Holders of not less than a majority in aggregate principal amount of the Securities of all series then Outstanding under the Indenture, considered as one class; provided, however, that if there shall be Securities of more than one series Outstanding under the Indenture and if a proposed supplemental indenture shall directly affect the rights of the Holders of Securities of one or more, but less than all, of such series, then the consent only of the Holders of a majority in aggregate principal amount of the Outstanding Securities of all series so directly affected, considered as one class, shall be required; and provided, further, that if the Securities of any series shall have been issued in more than one Tranche and if the proposed supplemental indenture shall directly affect the rights of the Holders of Securities of one or more, but less than all, of such Tranches, then the consent only of the Holders of a majority in aggregate principal amount of the Outstanding Securities of all Tranches so directly affected, considered as one class, shall be required; and provided, further, that the Indenture permits the Trustee to enter into one or more supplemental indentures for limited purposes without the consent of any Holders of Securities. The Indenture also contains EXHIBIT B-3 provisions permitting the Holders of a majority in principal amount of the Securities then Outstanding, on behalf of the Holders of all Securities, to waive compliance by the Company with certain provisions of the Indenture and certain past defaults under the Indenture and their consequences. Any such consent or waiver by the Holder of this Security shall be conclusive and binding upon such Holder and upon all future Holders of this Security and of any Security issued upon the registration of transfer hereof or in exchange therefor or in lieu hereof, whether or not notation of such consent or waiver is made upon this Security. As provided in the Indenture and subject to certain limitations therein set forth, this Security or any portion of the principal amount hereof will be deemed to have been paid for all purposes of the Indenture and to be no longer Outstanding thereunder, and, at the election of the Company, the Company's entire indebtedness in respect thereof will be satisfied and discharged, if there has been irrevocably deposited with the Trustee or any Paying Agent (other than the Company), in trust, money in an amount which will be sufficient and/or Eligible Obligations, the principal of and interest on which when due, without regard to any reinvestment thereof, will provide moneys which, together with moneys so deposited, will be sufficient, to pay when due the principal of and interest on this Security when due. As provided in the Indenture and subject to certain limitations therein set forth, the transfer of this Security is registrable in the Security Register, upon surrender of this Security for registration of transfer at the office of U.S. Bank Trust National Association, in New York, New York or such other office or agency as may be designated by the Company from time to time, duly endorsed by, or accompanied by a written instrument of transfer in form satisfactory to the Company and the Security Registrar duly executed by, the Holder hereof or his attorney duly authorized in writing, and thereupon one or more new Securities of this series of authorized denominations and of like tenor and aggregate principal amount, will be issued to the designated transferee or transferees. The Securities of this series are issuable only as registered Securities, without coupons, and in denominations of $1,000 and integral multiples thereof. As provided in the Indenture and subject to certain limitations therein set forth, Securities of this series are exchangeable for a like aggregate principal amount of Securities of the same series, of any authorized denominations, as requested by the Holder surrendering the same, and of like tenor upon surrender of the Security or Securities to be exchanged at the office of U.S. Bank Trust National Association, in New York, New York or such other office or agency as may be designated by the Company from time to time. No service charge shall be made for any such registration of transfer or exchange, but the Company may require payment of a sum sufficient to cover any tax or other governmental charge payable in connection therewith. Prior to due presentment of this Security for registration of transfer, the Company, the Trustee and any agent of the Company or the Trustee may treat the Person in whose name this Security is registered as the absolute owner hereof for all purposes, whether or not this Security be overdue, and neither the Company, the Trustee nor any such agent shall be affected by notice to the contrary. The Indenture and the Securities shall be governed by and construed in accordance with the laws of the State of New York. As used herein "Business Day" means any day, other than a Saturday or Sunday, which is not a day on which banking institutions or trust companies in The City of New York, New York or other city in which is located any office or agency maintained for the payment of principal or interest on this Security, are authorized or required by law, regulation or executive order to remain closed. All other terms used in EXHIBIT B-4 this Security which are defined in the Indenture shall have the meanings assigned to them in the Indenture. As provided in the Indenture, no recourse shall be had for the payment of the principal of or interest on any Securities, or any part thereof, or for any claim based thereon or otherwise in respect thereof, or of the indebtedness represented thereby, or upon any obligation, covenant or agreement under the Indenture, against, and no personal liability whatsoever shall attach to, or be incurred by, any incorporator, shareholder, officer or director, as such, past, present or future of the Company or of any predecessor or successor corporation (either directly or through the Company or a predecessor or successor corporation), whether by virtue of any constitutional provision, statute or rule of law, or by the enforcement of any assessment or penalty or otherwise; it being expressly agreed and understood that the Indenture and all the Securities are solely corporate obligations and that any such personal liability is hereby expressly waived and released as a condition of, and as part of the consideration for, the execution of the Indenture and the issuance of the Securities. Unless the certificate of authentication hereon has been executed by the Trustee or an Authenticating Agent by manual signature, this Security shall not be entitled to any benefit under the Indenture or be valid or obligatory for any purpose. EXHIBIT B-5 IN WITNESS WHEREOF, the Company has caused this instrument to be duly executed and its corporate seal to be hereunto affixed and attested. PUBLIC SERVICE COMPANY OF COLORADO By:_______________________________________ [Title] Attest:_______________________________ [Title] CERTIFICATE OF AUTHENTICATION This is one of the Securities of the series designated therein referred to in the within-mentioned Indenture. Dated:________________________________ U.S. BANK TRUST OR U.S. BANK TRUST NATIONAL ASSOCIATION, NATIONAL ASSOCIATION, as Trustee as Trustee By:_____________________________ By:____________________________ Authorized Officer AS AUTHENTICATING AGENT By:____________________________ Authorized Officer UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), TO THE COMPANY OR ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE, OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR IN SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE TO CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE, OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN. THIS SECURITY MAY NOT BE TRANSFERRED OR EXCHANGED, NOR MAY ANY PURPORTED TRANSFER BE REGISTERED, EXCEPT (i) THIS SECURITY MAY BE TRANSFERRED IN WHOLE, AND APPROPRIATE REGISTRATION OF TRANSFER EFFECTED, IF SUCH TRANSFER IS BY CEDE & CO., AS NOMINEE FOR THE DEPOSITORY TRUST COMPANY (THE "DEPOSITARY"), TO THE DEPOSITARY, OR BY THE DEPOSITARY TO ANOTHER NOMINEE THEREOF, OR BY ANY NOMINEE OF THE DEPOSITARY TO ANY OTHER NOMINEE THEREOF, OR BY THE DEPOSITARY OR ANY NOMINEE THEREOF TO ANY SUCCESSOR SECURITIES DEPOSITARY OR ANY NOMINEE THEREOF; AND (ii) THIS SECURITY MAY BE EXCHANGED FOR DEFINITIVE SECURITIES REGISTERED IN THE RESPECTIVE NAMES OF THE BENEFICIAL HOLDERS HEREOF, AND THEREAFTER SHALL BE TRANSFERABLE WITHOUT RESTRICTIONS IF: (A) THE DEPOSITARY, OR ANY SUCCESSOR SECURITIES DEPOSITARY, SHALL HAVE NOTIFIED THE COMPANY AND THE TRUSTEE THAT IT IS UNWILLING OR UNABLE TO CONTINUE TO ACT AS SECURITIES DEPOSITARY WITH RESPECT TO THE SECURITIES AND THE TRUSTEE SHALL NOT HAVE BEEN NOTIFIED BY THE COMPANY WITHIN NINETY (90) DAYS OF THE IDENTITY OF A SUCCESSOR EXHIBIT B-6 SECURITIES DEPOSITARY WITH RESPECT TO THE SECURITIES; OR (B) THE COMPANY SHALL HAVE DELIVERED TO THE TRUSTEE A COMPANY ORDER TO THE EFFECT THAT THE SECURITIES SHALL BE SO EXCHANGEABLE ON AND AFTER A DATE SPECIFIED THEREIN. EXHIBIT B-7 FOR VALUE RECEIVED the undersigned hereby sells, assigns and transfers unto ________________________________________________________________________________ [please insert social security or other identifying number of assignee] ________________________________________________________________________________ [please print or typewrite name and address of assignee] ________________________________________________________________________________ the within Security of PUBLIC SERVICE COMPANY OF COLORADO and does hereby irrevocably constitute and appoint __________________________________ , Attorney, to transfer said Security on the books of the within-mentioned Company, with full power of substitution in the premises. Dated:___________________________ _______________________________________ Notice: The signature to this assignment must correspond with the name as written upon the face of the Security in every particular without alteration or enlargement or any change whatsoever. EXHIBIT B-8 SCHEDULE A SUPPLEMENTAL INDENTURES

DATE OF PRINCIPAL SUPPLEMENTAL PRINCIPAL AMOUNT INDENTURE SERIES OF BONDS AMOUNT ISSUED OUTSTANDING --------- ---------------- -------------- ----------- November 1, 1993 Series No. 1 $134,500,000 $134,500,000 January 1, 1994 Series No. 2 due 2001 $102,667,000 None and Series No. 2 due 2024 $110,000,000 $110,000,000 September 2, 1994 None None None (Appointment of Successor Trustee) May 1, 1996 Series No. 3 $125,000,000 $125,000,000 November 1, 1996 Series No. 4 $250,000,000 $175,000,000 February 1, 1997 Series No. 5 $150,000,000 None April 1, 1998 Series No. 6 $250,000,000 None August 15, 2002 Series No. 7 $ 48,750,000 $ 48,750,000 September 1, 2002 Series No. 8 $600,000,000 None September 15, 2002 Series No. 9 $530,000,000 None April 1, 2003 Series No. 10 $600,000,000 $600,000,000 March 1, 2003 Series No. 11 $250,000,000 $250,000,000 May 1, 2003 Series No. 13 $350,000,000 $350,000,000

SCHEDULE A-1 -----END PRIVACY-ENHANCED MESSAGE-----

EX-1.01

                       PUBLIC SERVICE COMPANY OF COLORADO

                                  $575,000,000

    $300,000,000 4.375% First Collateral Trust Bonds, Series No. 14, due 2008
    $275,000,000 5.50% First Collateral Trust Bonds, Series No. 15, due 2014

                             UNDERWRITING AGREEMENT

                                                              New York, New York
                                                               September 2, 2003

Banc One Capital Markets, Inc.
1 Bank One Plaza
Chicago, Illinois 60670

McDonald Investments Inc.
800 Superior Avenue
Cleveland, Ohio 44114

UBS Securities LLC
677 Washington Boulevard
Stamford, Connecticut 06901

As Representatives of the several Underwriters

Ladies and Gentlemen:

         Public Service Company of Colorado, a corporation organized under the
laws of the State of Colorado (the "Company"), proposes to issue and sell to the
several parties named in Schedule I hereto (the "Underwriters"), for whom you
(the "Representatives") are acting as representatives, $300,000,000 principal
amount of the Company's 4.375% First Collateral Trust Bonds, Series No. 14, due
2008 and $275,000,000 principal amount of the Company's 5.50% First Collateral
Trust Bonds, Series No. 15, due 2014 (collectively, the "Bonds"). The Bonds are
to be issued under the Company's Indenture, dated as of October 1, 1993 (the
"Original Indenture") to U.S. Bank Trust National Association, as successor
trustee (the "Trustee"), as heretofore supplemented and as it will be further
supplemented by a supplemental indenture creating the Bonds (said Original
Indenture, as so supplemented and to be further supplemented, and said
supplemental indenture being hereafter referred to as the "Indenture" and the
"Supplemental Indenture", respectively). Certain terms used herein are defined
in Section 16 hereof.

         1.       Representations and Warranties. The Company represents and
warrants to, and agrees with, each Underwriter that:

                  (a)      (i) A registration statement on Form S-3 (File No.
         333-104504) in respect of the Bonds and certain other securities has
         been prepared and filed with the Commission in accordance with the
         provisions of the Act; such registration statement and any
         post-effective



         amendment thereto have been declared effective by the Commission; such
         registration statement in the form in which it became effective and
         (including the exhibits thereto, but excluding the Statements of
         Eligibility in Form T-1) is hereinafter called the "Registration
         Statement"; and the prospectus relating to the Bonds, in the form in
         which it was included in the Registration Statement at the time it
         became effective, as supplemented by the prospectus supplement
         containing the terms of the Bonds and the terms of the offering
         thereof, in the form in which it is first filed with the Commission
         pursuant to Rule 424(b) under the Act, is hereinafter called the
         "Prospectus";

                           (ii)     Pursuant to Rule 429 under the Act, the
         Prospectus will be used as a combined prospectus relating to the
         Registration Statement and to the registration statement filed by the
         Company with the Commission on June 29, 1999 (registration no.
         333-81791) which became effective on July 6, 1999; unless the context
         otherwise requires, all references in this Agreement to the
         Registration Statement shall be deemed to include such prior
         registration statement;

                           (iii)    Any reference herein to the Registration
         Statement, any preliminary prospectus or the Prospectus shall be deemed
         to refer to and include the documents incorporated by reference therein
         pursuant to Item 12 of Form S-3 under the Act, as of the effective date
         for purposes of the Registration Statement or the date thereof for
         purposes of any preliminary prospectus or the Prospectus; any reference
         to any amendment to the Registration Statement shall be deemed to refer
         to and include any annual report of the Company filed pursuant to
         Section 13(a) or 15(d) of the Exchange Act after the effective date of
         the Registration Statement that is incorporated by reference in the
         Registration Statement; and any reference to any amendment or
         supplement to any preliminary prospectus or the Prospectus shall be
         deemed to refer to and include any documents filed after the date of
         such preliminary prospectus or Prospectus, under the Exchange Act, and
         incorporated by reference in such preliminary prospectus or Prospectus.

                  (b)      No stop order suspending the effectiveness of the
         Registration Statement has been issued and no proceeding for that
         purpose has been initiated or, to the best knowledge of the Company,
         threatened by the Commission and no order preventing or suspending the
         use of any preliminary prospectus or the Prospectus has been issued by
         the Commission;

                  (c)      The Registration Statement, when it became effective,
         conformed, and any further amendments thereto, when they become
         effective, will conform, in all material respects to the requirements
         of the Act and the Trust Indenture Act, and the Prospectus and any
         amendments or supplements thereto, when filed with the Commission, will
         conform in all material respects to the requirements of the Act and the
         Trust Indenture Act;

                  (d)      The Registration Statement, when it became effective,
         and any further amendments thereto when they become effective, did not
         and will not contain an untrue statement of a material fact or omit to
         state a material fact required to be stated therein or necessary to
         make the statements therein not misleading; and the Prospectus and any
         amendments and supplements thereto, when they are filed or transmitted
         for filing with the Commission and at the Closing Date, will not
         include an untrue statement of a material fact or omit to state a
         material fact necessary in order to make the statements made, in light
         of the

                                        2


         circumstances under which they were made, not misleading; provided,
         however, that the representations and warranties contained in this
         subsection (d) shall not apply to statements or omissions made in
         reliance upon and in conformity with information furnished in writing
         by an Underwriter through the Representatives expressly for use in the
         Registration Statement, the Prospectus or any amendment or supplement
         to either thereof;

                  (e)      The documents incorporated by reference in the
         Registration Statement or Prospectus, when they were filed with the
         Commission, and any further documents so filed and incorporated by
         reference, when they are filed with the Commission or become effective,
         as the case may be, complied with and will comply in all material
         respects with the requirements of the Exchange Act or the Act, as the
         case may be;

                  (f)      The Company is not, and after giving effect to the
         offering and sale of the Bonds and the application of the proceeds
         thereof as described in the Prospectus will not be, an "investment
         company" or an entity "controlled" by an "investment company" within
         the meaning of the Investment Company Act of 1940, as amended, without
         taking account of any exemption arising out of the number of holders of
         the Company's securities;

                  (g)      The Company is subject to and in full compliance with
         the reporting requirements of Section 13 or Section 15(d) of the
         Exchange Act;

                  (h)      The statements in the Prospectus under the headings
         "Supplemental Description of the First Collateral Trust Bonds,"
         "Description of the First Collateral Trust Bonds," and "Description of
         the 1939 Mortgage" fairly summarize the matters therein described;

                  (i)      This Agreement has been duly authorized, executed and
         delivered by the Company;

                  (j)      The Indenture has been duly authorized and the
         Indenture (excluding the Supplemental Indenture) has been duly executed
         and delivered by the Company and is in due and proper form and
         (assuming the Indenture has been duly authorized, executed and
         delivered by the Trustee) when the Supplemental Indenture is duly
         executed and delivered the Indenture will constitute a legal, valid and
         binding mortgage of the Company, enforceable in accordance with its
         terms, except as enforcement thereof may be limited by laws and
         principles of equity affecting generally the enforcement of mortgagees'
         and other creditors' rights, including, without limitation, bankruptcy
         and insolvency laws and state laws which affect the enforcement of
         certain remedial provisions of the Indenture; provided, however, that
         such state laws will not render the remedies afforded by the Indenture
         inadequate for the practical realization of the benefit of the security
         provided thereby;

                  (k)      The issuance and sale by the Company of the Bonds
         pursuant to this Agreement have been duly authorized by all necessary
         corporate action; and, when issued, authenticated and delivered to the
         Underwriters pursuant to this Agreement against payment of the
         consideration therefor specified herein, the Bonds will be valid and
         binding obligations of the Company, enforceable in accordance with
         their terms, except as enforcement thereof may be limited by laws or
         principles of equity affecting generally the enforcement of mortgagees'
         and other creditors' rights, including, without limitation, bankruptcy
         and

                                        3


         insolvency laws and state laws which affect the enforcement of certain
         remedial provisions of the Indenture, and will be entitled to the
         benefits of the Indenture;

                  (l)      The PSCO 1939 Mortgage (as defined in the Indenture)
         has been duly authorized and the PSCO 1939 Mortgage (excluding the
         Mortgage Supplement) has been duly executed and delivered by the
         Company and is in due and proper form and (assuming the PSCO 1939
         Mortgage has been duly authorized, executed and delivered by the
         trustee thereunder) when the Mortgage Supplement is duly executed and
         delivered the PSCO 1939 Mortgage will constitute a legal, valid and
         binding mortgage of the Company, enforceable in accordance with its
         terms, except as enforcement thereof may be limited by laws and
         principles of equity affecting generally the enforcement of mortgagees'
         and other creditors' rights, including, without limitation, bankruptcy
         and insolvency laws and state laws which affect the enforcement of
         certain remedial provisions of the PSCO 1939 Mortgage; provided,
         however, that such state laws will not render the remedies afforded by
         the PSCO 1939 Mortgage inadequate for the practical realization of the
         benefit of the security provided thereby;

                  (m)      The issuance and delivery by the Company of the Class
         A Bonds (as defined in the Indenture) to be made the basis of the
         authentication and delivery of the Bonds (the "Class A Bonds") have
         been duly authorized by all necessary corporate action; and when (i)
         the Class A Bonds have been issued, authenticated and delivered to the
         Trustee pursuant to the Indenture and (ii) the Bonds have been issued,
         authenticated and delivered to the Underwriters pursuant to this
         Agreement against payment of the consideration therefor specified
         herein, the Class A Bonds will be valid and binding obligations of the
         Company, enforceable in accordance with their terms, except as
         enforcement thereof may be limited by laws or principles of equity
         affecting generally the enforcement of mortgagees' and other creditors'
         rights, including, without limitation, bankruptcy and insolvency laws
         and state laws which affect the enforcement of certain remedial
         provisions of the PSCO 1939 Mortgage, and will be entitled to the
         benefits of the PSCO 1939 Mortgage;

                  (n)      The issuance and sale of the Bonds, and the issuance
         and delivery of the Class A Bonds, have been duly authorized and
         approved by an order of The Public Utilities Commission of the State of
         Colorado and such order is final and in full force and effect on the
         date hereof, the time for appeal therefrom or review thereof or
         intervention with respect thereto having expired; no further approval,
         authorization, consent or other order of any public board or body is
         legally required in connection with the transactions contemplated by
         this Agreement, the Indenture or the PSCO 1939 Mortgage, except for the
         registration under the Act of the Bonds and as may be required under
         the blue sky laws of any jurisdiction in connection with the purchase
         and distribution of the Bonds by the Underwriters in the manner
         contemplated herein and in the Prospectus;

                  (o)      Neither the execution and delivery of this Agreement
         or the Supplemental Indenture, the issue and sale of the Bonds, nor the
         consummation of any other of the transactions herein or therein
         contemplated, nor the fulfillment of the terms hereof or thereof will
         conflict with, result in a breach or violation or imposition of any
         lien, charge or encumbrance upon any property or assets of the Company
         or any of its subsidiaries, other than the liens and security interests
         created by the Indenture and the PSCo 1939 Mortgage, pursuant to, (i)
         the charter or by-laws of the Company or any of its subsidiaries; (ii)
         the terms of any indenture, contract, lease, mortgage, deed of trust,
         note agreement, loan agreement or

                                        4


         other agreement, obligation, condition, covenant or instrument to which
         the Company or any of its subsidiaries is a party or bound or to which
         its or their property is subject; or (iii) any statute, law, rule,
         regulation, judgment, order or decree applicable to the Company or any
         of its subsidiaries of any court, regulatory body, administrative
         agency, governmental body, arbitrator or other authority having
         jurisdiction over the Company or any of its subsidiaries or any of its
         or their properties except, in the case of clause (ii), any such
         conflict, breach or violation which would not, individually or in the
         aggregate, have a material adverse change in the condition (financial
         or otherwise), prospects, earnings, business or properties of the
         Company and its subsidiaries taken as a whole, whether or not arising
         from transactions in the ordinary course of business;

                  (p)      The Company has good title to the properties
         specifically or generally described or referred to in the Indenture and
         in the PSCO 1939 Mortgage as subject to the respective liens thereof
         (except such property as may have been sold, exchanged or otherwise
         disposed of) subject only to (a) in the case of all such properties,
         the lien of the PSCO 1939 Mortgage and "permitted encumbrances" (as
         defined in the PSCO 1939 Mortgage) and (b) in the case of such
         properties which are used or to be used in or in connection with the
         Electric Utility Business (as defined in the Indenture) (whether or not
         such is the sole use of such property) the lien of the Indenture and
         Permitted Liens (as defined in the Indenture);

                  (q)      The Indenture constitutes a mortgage lien on the
         properties specifically or generally described or referred to therein
         as subject to the lien thereof (except such properties as may have been
         sold, exchanged or otherwise disposed of or released from the lien
         thereof in accordance with the terms thereof), subject to no liens
         prior to the lien of the Indenture other than Permitted Liens and the
         lien of the PSCO 1939 Mortgage; and the Indenture by its terms
         effectively subjects to the lien thereof all property (except property
         of the kinds specifically excepted from the lien of the Indenture)
         acquired by the Company after the date of execution and delivery of the
         Indenture and used or to be used in or in connection with the Electric
         Utility Business, subject to Permitted Liens, the lien of the PSCO 1939
         Mortgage, any lien thereon existing at the time of such acquisition and
         to any liens for unpaid portions of the purchase money placed thereon
         at the time of such acquisition, and also subject to the provisions of
         Article Thirteen of the Indenture and to certain possible claims of a
         trustee in bankruptcy and possible claims and taxes of the federal
         government;

                  (r)      The PSCO 1939 Mortgage constitutes a first mortgage
         lien on the properties specifically or generally described or referred
         to therein as subject to the lien thereof, including the shares of
         stock pledged thereunder (except such property as may have been sold,
         exchanged or otherwise disposed of or released from the lien thereof in
         accordance with the terms thereof), subject to no liens prior to the
         lien of the PSCO 1939 Mortgage other than "permitted encumbrances"; and
         the PSCO 1939 Mortgage by its terms effectively subjects to the lien
         thereof all property (except property of the kinds specifically
         excepted from the lien of the PSCO 1939 Mortgage) acquired by the
         Company after the date of the execution and delivery of the PSCO 1939
         Mortgage, subject to "permitted encumbrances", to any lien thereon
         existing at the time of such acquisition and to any liens for unpaid
         portions of the purchase money placed thereon at the time of such
         acquisition, and also subject to the provisions of Article XI of the
         PSCO 1939 Mortgage and to certain possible claims of a trustee in
         bankruptcy and possible claims and taxes of the federal government;

                                        5


                  (s)      The consolidated historical financial statements and
         schedules of the Company and its consolidated subsidiaries included or
         incorporated by reference in the Registration Statement and Prospectus
         present fairly in all material respects the financial condition,
         results of operations, cash flows and changes in financial position of
         the Company as of the dates and for the periods indicated, comply as to
         form with the applicable accounting requirements of the Act and the
         Exchange Act and have been prepared in conformity with GAAP throughout
         the periods involved (except as otherwise noted therein); the selected
         financial data set forth under the caption "Selected Consolidated
         Financial Data" in the Prospectus fairly present, on the basis stated
         in the Prospectus, the information included therein. Except as
         disclosed in or incorporated by reference in the Registration Statement
         and Prospectus, neither the Company nor any of its subsidiaries has any
         contingent obligations which are material to the Company and its
         consolidated subsidiaries taken as a whole;

                  (t)      Deloitte & Touche LLP, which audited the financial
         statements incorporated by reference in the Registration Statement and
         Prospectus, (A) are independent public accountants as required by the
         Act and the rules and regulations of the Commission thereunder and (B)
         do not provide to the Company or its subsidiaries any non-audit
         services which are prohibited by Section 10A(g) or (h) of the Exchange
         Act;

                  (u)      The statistical and market-related data and
         forward-looking statements (within the meaning of Section 27A of the
         Act and Section 21E of the Exchange Act) included or incorporated by
         reference in the Prospectus are based on or derived from sources that
         the Company believes to be reliable and accurate in all material
         respects and represent good faith estimates that are made on the basis
         of data derived from such sources;

                  (v)      Except as may otherwise be reflected in or
         contemplated by the Registration Statement and Prospectus, since the
         respective dates as of which information is given in the Registration
         Statement and Prospectus (i) there has been no material adverse change
         in the condition (financial or otherwise), prospects, earnings,
         business or properties of the Company and its subsidiaries taken as a
         whole, whether or not arising from transactions in the ordinary course
         of business and (ii) neither the Company nor any of its subsidiaries
         has entered into any transactions which are material to the Company and
         its subsidiaries taken as a whole, other than in the ordinary course of
         business; and, except as so reflected or contemplated, neither the
         Company nor any of its subsidiaries has any contingent obligations
         which are material to the Company and its subsidiaries taken as a
         whole;

                  (w)      Each of the Company and its subsidiaries has been
         duly incorporated and is validly existing as a corporation in good
         standing under the laws of the jurisdiction in which it is chartered or
         organized with full corporate power and authority to own or lease, as
         the case may be, and to operate its properties and conduct its business
         as described in the Registration Statement and Prospectus, and is duly
         qualified to do business as a foreign corporation and is in good
         standing under the laws of each jurisdiction in which such
         qualification is required, whether by reason of the ownership or
         leasing of property or the conduct of business, except where the
         failure to be so qualified would not have a material adverse change in
         the condition (financial or otherwise), prospects, earnings, business
         or properties of the Company and its subsidiaries taken as a whole,
         whether or not arising from transactions in the ordinary course of
         business;

                                        6


                  (x)      All the outstanding shares of capital stock of each
         subsidiary have been duly and validly authorized and issued and are
         fully paid and nonassessable, and, except as otherwise set forth in the
         Registration Statement and Prospectus, all outstanding shares of
         capital stock of the subsidiaries are owned by the Company either
         directly or through wholly-owned subsidiaries free and clear of any
         perfected security interest or any other security interests, claims,
         liens or encumbrances;

                  (y)      The Company has no subsidiaries which would be deemed
         significant subsidiaries under Regulation S-X;

                  (z)      Neither the Company nor any of its subsidiaries is in
         violation or default of (i) any provision of its charter or bylaws;
         (ii) the terms of any indenture, contract, lease, mortgage, deed of
         trust, note agreement, loan agreement or other agreement, obligation,
         condition, covenant or instrument to which it is a party or bound or to
         which its property is subject; or (iii) any statute, law, rule,
         regulation, judgment, order or decree applicable to the Company or any
         of its subsidiaries of any court, regulatory body, administrative
         agency, governmental body, arbitrator or other authority having
         jurisdiction over the Company or such subsidiary or any of its
         properties, as applicable except, in the case of clause (ii) or (iii),
         any such conflict, breach or violation which would not, individually or
         in the aggregate, have a material adverse change in the condition
         (financial or otherwise), prospects, earnings, business or properties
         of the Company and its subsidiaries taken as a whole, whether or not
         arising from transactions in the ordinary course of business;

                  (aa)     The Company, either directly or through its parent,
         has filed all foreign, federal, state and local tax returns that are
         required to be filed or has requested extensions thereof (except in any
         case in which the failure so to file would not have a material adverse
         effect on the condition (financial or otherwise), prospects, earnings,
         business or properties of the Company and its subsidiaries, taken as a
         whole, whether or not arising from transactions in the ordinary course
         of business, except as set forth in or contemplated in the Registration
         Statement and Prospectus and has paid, either directly or through its
         parent, all taxes required to be paid by it and any other assessment,
         fine or penalty levied against it, to the extent it has notice that any
         of the foregoing is due and payable, except for any such assessment,
         fine or penalty that is currently being contested in good faith or as
         would not have a material adverse effect on the condition (financial or
         otherwise), prospects, earnings, business or properties of the Company
         and its subsidiaries, taken as a whole, whether or not arising from
         transactions in the ordinary course of business, except as set forth in
         or contemplated in the Registration Statement and Prospectus;

                  (bb)     The Company and each of its subsidiaries are insured
         by insurers of recognized financial responsibility against such losses
         and risks and in such amounts as are prudent and customary in the
         businesses in which they are engaged; all material policies of
         insurance and fidelity or surety bonds insuring the Company or any of
         its subsidiaries or their respective businesses, assets, employees,
         officers and directors are in full force and effect; the Company and
         its subsidiaries are in compliance with the terms of such material
         policies and instruments in all material respects; and there are no
         material claims by the Company or any of its subsidiaries under any
         such policy or instrument as to which any insurance company is denying
         liability or defending under a reservation of rights clause; neither
         the Company nor any such subsidiary has been refused any material
         insurance coverage sought or applied for;

                                        7


                  (cc)     No subsidiary of the Company is currently prohibited,
         directly or indirectly, from paying any dividends to the Company, from
         making any other distribution on such subsidiary's capital stock, from
         repaying to the Company any loans or advances to such subsidiary from
         the Company or from transferring any of such subsidiary's property or
         assets to the Company or any other subsidiary of the Company, except as
         described in or contemplated by the Registration Statement and
         Prospectus;

                  (dd)     Neither the Company, nor any of its subsidiaries, nor
         any director, officer, agent, employee or other person or entity acting
         on behalf of the Company or any of its subsidiaries has, in the course
         of its actions for, or on behalf of, the Company, used any corporate
         funds for any unlawful contribution, gift, entertainment or other
         unlawful expenses relating to political activity; made any direct or
         indirect unlawful payment to any foreign or domestic government
         official or employee from corporate funds; violated or is in violation
         of any provision of the U.S. Foreign Corrupt Practices Act of 1977, as
         amended; or made any unlawful bribe, rebate, payoff, influence payment,
         kickback or other unlawful payment to any foreign or domestic
         government official or employee;

                  (ee)     (A) The Company has established and maintains
         disclosure controls and procedures (as such term is defined in Rule
         13a-15(e) under the Exchange Act, "Disclosure Controls"); and such
         Disclosure Controls are (i) designed to ensure that material
         information relating to the Company, including its consolidated
         subsidiaries, is properly recorded, processed, summarized and
         communicated to the Company's senior management, including its
         principal executive officer and its principal financial officer, by
         others within those entities as appropriate to allow timely decisions
         regarding required disclosure, (ii) evaluated by the Company's senior
         management on a quarterly basis and (iii) to the best knowledge of the
         Company, effective in all material respects to perform the functions
         for which they were established;

                           (B)      The Company has designed and maintains
         internal control over financial reporting (as such term is defined in
         Rule 13a-15(f) under the Exchange Act, "Reporting Controls"); and the
         Reporting Controls are (i) designed to provide reasonable assurance
         regarding the reliability of financial reporting and the preparation of
         financial statements for external purposes in accordance with GAAP and
         include, without limitation, those processes specifically referred to
         in Rule 13a-15(f) and (ii) to the best knowledge of the Company,
         effective to perform the functions for which they are maintained;

                           (C)      The Company has devised and maintains in
         effect a system of internal accounting controls ("Accounting
         Controls"); and such Accounting Controls are sufficient to provide
         reasonable assurances that (i) transactions involving the Company and
         its subsidiaries are executed in accordance with management's general
         or specific authorization; (ii) transactions are recorded as necessary
         (I) to permit preparation of financial statements in conformity with
         generally accepted accounting principles and (II) to maintain
         accountability for assets; (iii) access to assets is permitted only in
         accordance with management's general or specific authorization; and
         (iv) the recorded accountability for assets is compared with the
         existing assets at reasonable intervals and appropriate action is taken
         with respect to any differences;

                           (D)      Based on the most recent evaluation of the
         Company's internal controls referred to above, all significant
         deficiencies in the design or operation of such

                                        8


         internal controls which could adversely affect the Company's ability to
         record, process, summarize and report financial data required to be
         disclosed by the Company in its Exchange Act reports within the time
         periods specified in the Exchange Act, any material weaknesses in such
         internal controls and any fraud, whether or not material, that involves
         management or other employees who have a significant role in such
         internal controls have been identified and reported to the Company's
         auditors and the audit committee of the board of directors; and all
         such deficiencies and weaknesses, if any, have been rectified;

                  (ff)     Except as set forth in, or incorporated by reference
         in, the Registration Statement and Prospectus, the Company and its
         subsidiaries (i) are in compliance with any and all applicable federal,
         state and local laws and regulations relating to the protection of
         human health and safety, the environment or hazardous or toxic
         substances or wastes, pollutants or contaminants ("Environmental
         Laws"), (ii) have received all permits, licenses or other approvals
         required of them under applicable Environmental Laws to conduct their
         respective businesses, (iii) are in compliance with all terms and
         conditions of any such permits, licenses or approvals, and (iv) have
         not received notice of any actual or potential liability for the
         investigation or remediation of any disposal or release of hazardous or
         toxic substances or wastes, pollutants or contaminants, except where
         such non-compliance with Environmental Laws, failure to receive
         required permits, licenses or other approvals, or any such liability
         would not, individually or in the aggregate, have a material adverse
         change in the condition (financial or otherwise), prospects, earnings,
         business or properties of the Company and its subsidiaries, taken as a
         whole, whether or not arising from transactions in the ordinary course
         of business;

                  (gg)     With respect to each employee benefit plan (as
         defined in Section 3(3) of the Employee Retirement Income Security Act
         of 1974, as amended ("ERISA")) which the Company or any other
         organization that together with the Company is treated as a single
         employer under Sections 414(b), (c), (m) or (o) of the Internal Revenue
         Code of 1986, as amended (the "Code") (an "ERISA Affiliate"), has at
         any time sponsored, maintained, contributed to or been obligated to
         contribute to (a "Plan"): (i) the Company and each ERISA Affiliate have
         administered and operated each Plan sponsored or maintained by the
         Company or an ERISA Affiliate in compliance with ERISA, the Code and
         other applicable laws except for such instances of noncompliance as
         have not resulted in and could not reasonably be expected to result in
         a material liability to the Company or ERISA Affiliate; (ii) each Plan
         sponsored or maintained by the Company or an ERISA Affiliate intended
         to qualify under Section 401(a) of the Code so qualifies and to the
         Company's knowledge nothing has occurred, whether by action or failure
         to act, which could reasonably be expected to cause the loss of such
         qualification of any such Plan; (iii) neither the Company nor any ERISA
         Affiliate has incurred, and to the Company's knowledge no event,
         transaction or condition has occurred or exists under which the Company
         or any ERISA Affiliate could reasonably expect to incur, any material
         liability or the imposition of any lien on any of the rights,
         properties or assets of the Company or any ERISA Affiliate pursuant to
         Title I or Title IV of ERISA (other than routine claims for benefits)
         or applicable penalty or excise provisions of the Code; (iv) there has
         been no reportable event (within the meaning of Section 4043 of ERISA)
         with respect to any Plan subject to Title IV of ERISA that is sponsored
         or maintained by the Company or an ERISA Affiliate for which the 30-day
         reporting requirement has not been waived which could reasonably be
         expected to result in a material liability under Title IV of ERISA to
         the Company or an ERISA Affiliate; (v) no accumulated funding
         deficiency (within the meaning of Section 302 of ERISA and Section

                                        9


         412 of the Code), whether or not waived, exists with respect to any
         Plan subject to Title IV of ERISA that is sponsored or maintained by
         the Company; and (vi) neither the Company nor any ERISA Affiliate has
         incurred, and to the Company's knowledge no event, transaction or
         condition has occurred or exists under which the Company or any ERISA
         Affiliate could reasonably expect to incur, any material liability with
         respect to termination of, or withdrawal from, any Plan subject to
         Title IV of ERISA;

                  (hh)     The franchises held by the Company and its
         subsidiaries, together with the applicable Certificates of Convenience
         and Necessity issued by The Public Utilities Commission of the State of
         Colorado, give the Company and such subsidiaries all necessary
         authority for the maintenance and operation of their respective
         properties and business as now conducted, and are free from burdensome
         restrictions or conditions of an unusual character.

         Any certificate signed by any officer of the Company and delivered to
the Representatives or counsel for the Representatives in connection with the
offering of the Bonds shall be deemed a representation and warranty by the
Company, as to matters covered thereby, to each Underwriter.

         2.       Purchase and Sale. Subject to the terms and conditions and in
reliance upon the representations and warranties herein set forth, the Company
agrees to sell to each Underwriter, severally and not jointly, and each
Underwriter agrees, severally and not jointly, to purchase from the Company, (a)
at a purchase price of 99.280% of the principal amount thereof, plus accrued
interest, if any, from September 9, 2003 to the Closing Date, the principal
amount of 4.375% First Collateral Trust Bonds, Series No. 14 due 2008 set forth
opposite such Underwriter's name in Schedule I hereto and (b) at a purchase
price of 98.611% of the principal amount thereof, plus accrued interest, if any,
from September 9, 2003 to the Closing Date, the principal amount of 5.50% First
Collateral Trust Bonds, Series No. 15, due 2014 set forth opposite such
Underwriters name in Schedule 1 hereto.

         It is understood that the several underwriters propose to offer the
Bonds for sale to the public as set forth in the Prospectus.

         3.       Delivery and Payment. Delivery of and payment for the Bonds
shall be made at 10:00 A.M., New York City time, on September 9, 2003, or at
such time on such later date as the Representatives shall designate, which date
and time may be postponed by agreement between the Representatives and the
Company or as provided in Section 8 hereof (such date and time of delivery and
payment for the Bonds being herein called the "Closing Date"). Delivery of the
Bonds shall be made to the Representatives for the respective accounts of the
several Underwriters against payment by the several Underwriters through the
Representatives of the purchase price thereof to or upon the order of the
Company by wire transfer payable in same-day funds to the account specified by
the Company. Delivery of the Bonds shall be made through the facilities of The
Depository Trust Company.

         4.       Agreements. The Company agrees with each Underwriter:

                  (a)      To prepare the Prospectus in a form approved by the
         Representatives and to file such Prospectus pursuant to Rule 424(b)
         under the Act not later than the Commission's close of business on the
         second business day following the execution and delivery of this
         Agreement; to make no further amendment or any supplement to the
         Registration Statement or Prospectus prior to the Closing Date which
         shall be reasonably disapproved by the

                                       10


         Representatives promptly after reasonable notice thereof; during the
         period for which a prospectus is required to be delivered under the Act
         in connection with the offering and sale of the Bonds, to advise the
         Representatives, promptly after it receives notice thereof, of the time
         when any amendment to the Registration Statement has been filed or
         becomes effective or any supplement to the Prospectus or any amended
         Prospectus has been filed and to furnish the Representatives with
         copies thereof; to file promptly all reports and any definitive proxy
         or information statements required to be filed by the Company with the
         Commission pursuant to Section 13(a), 13(c), 14 or 15(d) of the
         Exchange Act subsequent to the date of the Prospectus and for so long
         as the delivery of a prospectus is required under the Act in connection
         with the offering or sale of the Bonds; to advise the Representatives,
         promptly after it receives notice thereof, of the issuance by the
         Commission of any stop order or of any order preventing or suspending
         the use of any prospectus, of the suspension of the qualification of
         the Bonds for offering or sale in any jurisdiction, of the initiation
         or threatening of any proceeding for any such purpose, or of any
         request by the Commission for the amending or supplementing of the
         Registration Statement or the Prospectus or for additional information;
         to use its best efforts to prevent the issuance of any stop order or of
         any order preventing or suspending the use of any prospectus or
         suspending any such qualification, and, in the event of the issuance of
         any such order, promptly to use its best efforts to obtain the
         withdrawal of such order;

                  (b)      Promptly from time to time to take such action as the
         Representatives may reasonably request to qualify the Bonds for
         offering and sale under the securities laws of such jurisdictions as
         the Representatives may request and to comply with such laws so as to
         permit the continuance of sales and dealings therein in such
         jurisdictions for as long as may be necessary to complete the
         distribution of the Bonds, provided that in connection therewith the
         Company shall not be required to qualify as a foreign corporation or to
         file a general consent to service of process in any jurisdiction;

                  (c)      Prior to 10:00 a.m., New York City time, on the third
         Business Day next succeeding the date of this Agreement and from time
         to time, to furnish the Underwriters with written and electronic copies
         of the Prospectus in such quantities as the Representatives may from
         time to time reasonably request, and, if the delivery of a prospectus
         is required under the Act at any time in connection with the offering
         or sale of the Bonds and if at such time any event shall have occurred
         as a result of which the Prospectus as then amended or supplemented
         would include an untrue statement of a material fact or omit to state
         any material fact necessary in order to make the statements therein, in
         the light of the circumstances under which they were made when such
         Prospectus is delivered, not misleading, or, if for any other reason it
         shall be necessary during such period to amend or supplement the
         Prospectus or to file under the Exchange Act any document incorporated
         by reference in the Prospectus in order to comply with the Act, the
         Exchange Act or the Trust Indenture Act, to notify the Representatives
         and upon their reasonable request to file such document and to prepare
         and furnish without charge to each Underwriter and to any dealer in
         securities as many written and electronic copies as the Representatives
         may from time to time reasonably request of an amended Prospectus or a
         supplement to the Prospectus which will correct such statement or
         omission or effect such compliance;

                  (d)      To make generally available to its securityholders
         and to the Representatives as soon as practicable, but in any event not
         later than eighteen months after the effective date of the Registration
         Statement (as defined in Rule 158(c) under the Act), an earnings

                                       11


         statement of the Company and its subsidiaries (which need not be
         audited) covering a period of at least 12 months beginning after the
         later of (i) the effective date of the most recent post-effective
         amendment to the Registration Statement to become effective prior to
         the date of this Agreement and (ii) the date of the Company's most
         recent Annual Report on Form 10-K filed with the Commission prior to
         the date of this Agreement, which will satisfy the provisions of
         Section 11(a) of the Act and the rules and regulations thereunder
         including Rule 158;

                  (e)      For a period of 14 days following the Execution Time,
         without the prior written consent of the Representatives, not to offer,
         sell or contract to sell, or otherwise dispose of (or enter into any
         transaction which is designed to, or might reasonably be expected to,
         result in the disposition (whether by actual disposition or effective
         economic disposition due to cash settlement or otherwise) by the
         Company, directly or indirectly, or announce the offering of) any
         long-term debt securities issued or guaranteed by the Company, other
         than the Bonds and the bonds contemplated by any Shelf Registration
         Statement or Exchange Offer Registration Statement (as such terms are
         defined in the Registration Rights Agreement dated March 14, 2003,
         between the Company and Banc One Capital Markets Inc. and UBS
         Securities LLC, as representatives of the Initial Purchasers (as
         identified therein));

                  (f)      To use the net proceeds received by it from the sale
         of the Bonds pursuant to this Agreement in the manner specified in the
         Prospectus under the caption "Use of Proceeds";

                  (g)      To pay the costs and expenses relating to the
         following matters: (i) the preparation of the Supplemental Indenture
         the issuance of the Bonds and the fees of the Trustee; (ii) the
         preparation, printing and filing of the Registration Statement
         (including all exhibits thereto), the preliminary prospectus, the
         Prospectus (including all documents incorporated by reference therein)
         and any amendments thereof or supplements thereto and the printing and
         furnishing of such copies of each thereof to the Underwriters and to
         dealers (including postage, air freight charges and charges for
         counting and packaging), as may be reasonably requested for use in
         connection with the offering and sale of the Bonds; (iii) the
         preparation, printing, authentication, issuance and delivery of
         certificates for the Bonds, including any stamp or transfer taxes in
         connection with the original issuance and sale of the Bonds; (iv) the
         printing (or reproduction) and delivery of this Agreement, any blue sky
         memorandum and all other agreements or documents printed (or
         reproduced) and delivered in connection with the offering of the Bonds;
         (v) any registration or qualification of the Bonds for offer and sale
         under the securities or blue sky laws of the several states (including
         filing fees and the reasonable fees and expenses of counsel for the
         Underwriters relating to such registration and qualification); (vi) the
         transportation and other expenses incurred by or on behalf of Company
         representatives in connection with presentations to prospective
         purchasers of the Bonds; (vii) the fees and expenses of the Company's
         accountants and counsel (including local and special counsel); (viii)
         the fees and expenses of any rating agencies rating the Bonds and (ix)
         all other costs and expenses incident to the performance by the Company
         of its obligations hereunder.

         5.       Conditions to the Obligations of the Underwriters. The
obligations of the Underwriters to purchase the Bonds shall be subject to the
accuracy of the representations and warranties on the part of the Company
contained herein at the Execution Time and the Closing Date,

                                       12


to the accuracy of the statements of the Company made in any certificates
pursuant to the provisions hereof, to the performance by the Company of its
obligations hereunder and to the following additional conditions:

                  (a)      (i) The Prospectus shall have been filed with the
         Commission pursuant to Rule 424(b) within the applicable time period
         prescribed for such filing by the rules and regulations under the Act
         and in accordance with Section 4(a) hereof; (ii) no stop order
         suspending the effectiveness of the Registration Statement or any part
         thereof shall have been issued and no proceeding for that purpose shall
         have been initiated or threatened by the Commission; and (iii) all
         requests for additional information on the part of the Commission shall
         have been complied with to the Representatives' reasonable
         satisfaction;

                  (b)      At the Closing Date, the Representatives shall have
         received opinions, dated the Closing Date, of Ann E. Hopfenbeck,
         Assistant General Counsel, Xcel Energy Services, Attorney for the
         Company, Jones Day and LeBoeuf, Lamb, Greene and MacRae, LLP, counsel
         for the Company, substantially to the effect set forth in Exhibit A
         hereto and other related matters as the Representatives may reasonably
         require, with reproduced or conformed copies thereof for each of the
         Purchasers, and the Company shall have furnished to such counsel such
         documents as they request for the purpose of enabling them to pass upon
         such matters;

                  (c)      At the Closing Date, the Representatives shall have
         received from Dewey Ballantine LLP, counsel for the Underwriters, such
         opinion or opinions, dated the Closing Date and addressed to the
         Representatives, with respect to the issuance and sale of the Bonds,
         the Indenture, the Registration Statement, the Prospectus and other
         related matters as the Representatives may reasonably require, and the
         Company shall have furnished to such counsel such documents as they
         request for the purpose of enabling them to pass upon such matters;

                  (d)      The Company shall have furnished to the
         Representatives a certificate of the Company, signed by the President
         or any Vice President and the Treasurer of the Company, dated the
         Closing Date, to the effect that the signer of such certificate has
         carefully examined the Registration Statement and all amendments
         thereto, the Prospectus and all amendments or supplements thereto and
         this Agreement and that:

                           (i)      the representations and warranties of the
         Company in this Agreement are true and correct in all material respects
         on and as of the Closing Date with the same effect as if made on the
         Closing Date, and the Company has complied with all the agreements and
         satisfied all the conditions on its part to be performed or satisfied
         hereunder at or prior to the Closing Date; and

                           (ii)     since the date of the most recent financial
         statements included or incorporated by reference in the Prospectus,
         there has been no material adverse change in the condition (financial
         or otherwise), prospects, earnings, business or properties of the
         Company and its subsidiaries taken as a whole, whether or not arising
         from transactions in the ordinary course of business, except as set
         forth in or contemplated by the Prospectus.

                  (e)      At the Execution Time and at the Closing Date, the
         Company shall have requested and caused Deloitte & Touche LLP to
         furnish to the Representatives letters, dated

                                       13


         respectively as of the Execution Time and as of the Closing Date,
         substantially to the effect set forth in Exhibit B hereto;

                  (f)      Subsequent to the Execution Time or, if earlier, the
         dates as of which information is given in the Prospectus, there shall
         not have been (i) any change or decrease specified in the letter or
         letters referred to in paragraph (e) of this Section 5; or (ii) any
         change, or any development involving a prospective change, in or
         affecting the financial condition, business or properties of the
         Company and its subsidiaries, taken as a whole, whether or not arising
         from transactions in the ordinary course of business, except as set
         forth in or contemplated in the Prospectus the effect of which, in any
         case referred to in clause (i) or (ii) above, is, in the sole judgment
         of the Representatives, so material and adverse as to make it
         impractical or inadvisable to market the Bonds as contemplated by the
         Prospectus.

                  (g)      Subsequent to the Execution Time, there shall not
         have been any decrease in the rating or outlook of any of the Company's
         debt securities by any "nationally recognized statistical rating
         organization" (as defined for purposes of Rule 436(g) under the Act) or
         any public announcement of any intended or potential decrease in any
         such rating or outlook or of a possible change in any such rating or
         outlook that does not indicate the direction of the possible change;

                  (h)      The Company shall have complied with the provisions
         of Section 4(c) hereof with respect to the furnishing of prospectuses.

                  (i)      Prior to the Closing Date, the Company shall have
         furnished to the Representatives such further information, certificates
         and documents as the Representatives may reasonably request.

         If any of the conditions specified in this Section 5 shall not have
been fulfilled in all material respects when and as provided in this Agreement,
or if any of the opinions and certificates mentioned above or elsewhere in this
Agreement shall not be in all material respects reasonably satisfactory in form
and substance to the Representatives and counsel for the Underwriters, this
Agreement and all obligations of the Underwriters hereunder may be cancelled at,
or at any time prior to, the Closing Date by the Representatives. Notice of such
cancellation shall be given to the Company in writing or by telephone or
facsimile confirmed in writing.

         The documents required to be delivered by this Section 5 will be
delivered at the office of counsel for the Company, at Jones Day, on the Closing
Date.

         6.       Reimbursement of Expenses. If the sale of the Bonds provided
for herein is not consummated because any condition to the obligations of the
Underwriters set forth in Section 5 hereof is not satisfied, because of any
termination pursuant to clause (i) of Section 9 hereof or because of any
refusal, inability or failure on the part of the Company to perform any
agreement herein or comply with any provision hereof, other than by reason of a
default by any of the Underwriters, the Company will reimburse the Underwriters
on demand for all out-of-pocket expenses (including reasonable fees and
disbursements of counsel) that shall have been incurred by them in connection
with the proposed purchase and sale of the Bonds.

         7.       Indemnification and Contribution. (a) The Company agrees to
indemnify and hold harmless each Underwriter, the directors, members, officers,
employees and agents of each

                                       14


Underwriter and each person who controls any Underwriter within the meaning of
either the Act or the Exchange Act against any and all losses, claims, damages
or liabilities, joint or several, to which they or any of them may become
subject under the Act, the Exchange Act or other Federal or state statutory law
or regulation, at common law or otherwise, insofar as such losses, claims,
damages or liabilities (or actions in respect thereof) arise out of or are based
upon any untrue statement or alleged untrue statement of a material fact
contained in the Registration Statement or any amendment thereto, in any
preliminary prospectus or preliminary prospectus supplement or in the Prospectus
or any amendment or supplement thereto, or arise out of or are based upon the
omission or alleged omission to state therein a material fact required to be
stated therein or necessary to make the statements therein, in the light of the
circumstances under which they were made, not misleading, and agrees to
reimburse each such indemnified party, as incurred, for any legal or other
expenses reasonably incurred by them in connection with investigating or
defending any such loss, claim, damage, liability or action; provided, however,
that the Company will not be liable in any such case to the extent that any such
loss, claim, damage or liability arises out of or is based upon any such untrue
statement or alleged untrue statement or omission or alleged omission made in
the Registration Statement or any amendment thereto, in any preliminary
prospectus or preliminary prospectus supplement or in the Prospectus or any
amendment or supplement thereto, in reliance upon and in conformity with written
information furnished to the Company by or on behalf of any Underwriter through
the Representatives specifically for inclusion therein; provided, further, that
with respect to any such untrue statement in or omission from any preliminary
prospectus, the indemnity contained in this paragraph (a) shall not inure to the
benefit of any Underwriter or its directors, members, officers, employees and
agents, and each person, if any, who controls such Underwriter to the extent
that the sale to the person asserting any such loss, claim, damage or liability
was an initial sale by such Underwriter and any such loss, claim, damage or
liability of or with respect to such Underwriter results from the fact that both
(i) to the extent required by applicable law, a copy of the Prospectus was not
sent or given to such person at or prior to the written confirmation of the sale
of the Bonds to such person and (ii) the untrue statement in or omission from
such preliminary prospectus was corrected in the Prospectus unless, in either
case, such failure to deliver the Prospectus was a result of non-compliance by
the Company with the provisions of Section 4(c) hereof. This indemnity agreement
will be in addition to any liability which the Company may otherwise have;

                  (b)      Each Underwriter severally and not jointly agrees to
indemnify and hold harmless the Company, and each of its directors, officers,
employees and agents, and each person who controls the Company within the
meaning of either the Act or the Exchange Act, to the same extent as the
foregoing indemnity from the Company to each Underwriter, but only with
reference to written information relating to such Underwriter furnished to the
Company by or on behalf of such Underwriter through the Representatives
specifically for inclusion in the Prospectus or any amendment or supplement
thereto. This indemnity agreement will be in addition to any liability which
such Underwriter may otherwise have. The Company acknowledges that the
statements set forth in (i) the last sentence of the cover page of the
Prospectus regarding the delivery of the Bonds, (ii) the third paragraph of text
under the caption "Underwriting" in the Prospectus, (iii) the first, second and
third sentences of the sixth paragraph of text under the caption "Underwriting"
in the Prospectus and (iv) the seventh and eighth paragraphs of text under the
caption "Underwriting" in the Prospectus constitute the only information
furnished in writing by or on behalf of the Underwriters for inclusion in the
Prospectus (or any amendment or supplement thereto);

                  (c)      Promptly after receipt by an indemnified party under
this Section 7 of notice of the commencement of any action, such indemnified
party will, if a claim in respect thereof is to be made against the indemnifying
party under this Section 7, notify the indemnifying party in writing of

                                       15


the commencement thereof; but the failure so to notify the indemnifying party
(i) will not relieve it from liability under paragraph (a) or (b) above unless
and to the extent it did not otherwise learn of such action and such failure
results in the forfeiture by the indemnifying party of substantial rights and
defenses; and (ii) will not, in any event, relieve the indemnifying party from
any obligations to any indemnified party other than the indemnification
obligation provided in paragraph (a) or (b) above. The indemnifying party shall
be entitled to appoint counsel of the indemnifying party's choice at the
indemnifying party's expense to represent the indemnified party in any action
for which indemnification is sought (in which case the indemnifying party shall
not thereafter be responsible for the fees and expenses of any separate counsel
retained by the indemnified party or parties except as set forth below);
provided, however, that such counsel shall be reasonably satisfactory to the
indemnified party. Notwithstanding the indemnifying party's election to appoint
counsel to represent the indemnified party in an action, the indemnified party
shall have the right to employ separate counsel (including local counsel), and
the indemnifying party shall bear the reasonable fees, costs and expenses of
such separate counsel if (i) the use of counsel chosen by the indemnifying party
to represent the indemnified party would present such counsel with a conflict of
interest; (ii) the actual or potential defendants in, or targets of, any such
action include both the indemnified party and the indemnifying party and the
indemnified party shall have reasonably concluded that there may be legal
defenses available to it and/or other indemnified parties which are different
from or additional to those available to the indemnifying party; (iii) the
indemnifying party shall not have employed counsel satisfactory to the
indemnified party to represent the indemnified party within a reasonable time
after notice of the institution of such action; or (iv) the indemnifying party
shall authorize the indemnified party to employ separate counsel at the expense
of the indemnifying party, it being understood, however, that in each case the
indemnifying party shall not, in connection with any one such action or separate
but substantially similar or related actions in the same jurisdiction arising
out of the same general allegations or circumstances, be liable for the
reasonable fees and expenses of more than one separate firm of attorneys (in
addition to any local counsel) at any time for all such indemnified parties,
which firm shall be designated by the Representatives if the indemnified parties
consist of the Underwriters or their directors, members, officers, employees or
agents. An indemnifying party will not, without the prior written consent of the
indemnified parties, settle or compromise or consent to the entry of any
judgment with respect to any pending or threatened claim, action, suit or
proceeding in respect of which indemnification or contribution may be sought
hereunder (whether or not the indemnified parties are actual or potential
parties to such claim or action) unless such settlement, compromise or consent
includes an unconditional release of each indemnified party from all liability
arising out of such claim, action, suit or proceeding;

                  (d)      In the event that the indemnity provided in paragraph
(a) or (b) of this Section 7 is for any reason held to be unenforceable by an
indemnified party although applicable in accordance with its terms, the Company
and the Underwriters agree to contribute to the aggregate losses, claims,
damages and liabilities (including legal or other expenses reasonably incurred
in connection with investigating or defending same) (collectively, "Losses") to
which the Company and one or more of the Underwriters may be subject in such
proportion as is appropriate to reflect the relative benefits received by the
Company on the one hand and by the Underwriters on the other from the offering
of the Bonds; provided, however, that in no case shall any Underwriter (except
as may be provided in any agreement among the Underwriters relating to the
offering of the Bonds) be responsible for any amount in excess of the purchase
discount or commission applicable to the Bonds purchased by such Underwriter
hereunder; provided, further, that each Underwriter's obligation to contribute
to Losses hereunder shall be several and not joint. If the allocation provided
by the immediately preceding sentence is unavailable for any reason, the Company
and the Underwriters shall contribute in such proportion as is appropriate to
reflect not only such relative benefits but also

                                       16


the relative fault of the Company on the one hand and of the Underwriters on the
other in connection with the statements or omissions which resulted in such
Losses, as well as any other relevant equitable considerations. Benefits
received by the Company shall be deemed to be equal to the total net proceeds
from the offering (before deducting expenses) received by it, and benefits
received by the Underwriters shall be deemed to be equal to the total
underwriting discounts and commissions in each case set forth on the cover of
the Prospectus Supplement. Relative fault shall be determined by reference to,
among other things, whether any untrue or any alleged untrue statement of a
material fact or the omission or alleged omission to state a material fact
relates to information provided by the Company on the one hand or the
Underwriters on the other, the intent of the parties and their relative
knowledge, information and opportunity to correct or prevent such untrue
statement or omission. The Company and the Underwriters agree that it would not
be just and equitable if contribution were determined by pro rata allocation or
any other method of allocation which does not take account of the equitable
considerations referred to above. Notwithstanding the provisions of this
paragraph (d), no person guilty of fraudulent misrepresentation (within the
meaning of Section 11(f) of the Act) shall be entitled to contribution from any
person who was not guilty of such fraudulent misrepresentation. For purposes of
this Section 7, each person who controls an Underwriter within the meaning of
either the Act or the Exchange Act and each director, member, officer, employee
and agent of an Underwriter shall have the same rights to contribution as such
Underwriter, and each person who controls the Company within the meaning of
either the Act or the Exchange Act and each officer, director, member, employee
or agent of the Company shall have the same rights to contribution as the
Company, subject in each case to the applicable terms and conditions of this
paragraph (d);

         8.       Default by an Underwriter. If any one or more Underwriters
shall fail to purchase and pay for any of the Bonds agreed to be purchased by
such Underwriter hereunder and such failure to purchase shall constitute a
default in the performance of its or their obligations under this Agreement, the
remaining Underwriters shall be obligated severally to take up and pay for (in
the respective proportions which the amount of Bonds set forth opposite their
names in Schedule I hereto bears to the aggregate amount of Bonds set forth
opposite the names of all the remaining Underwriters) the Bonds which the
defaulting Underwriter or Underwriters agreed but failed to purchase; provided,
however, that in the event that the aggregate amount of Bonds which the
defaulting Underwriter or Underwriters agreed but failed to purchase shall
exceed 10% of the aggregate amount of Bonds set forth in Schedule I hereto, the
remaining Underwriters shall have the right to purchase all, but shall not be
under any obligation to purchase any, of the Bonds, and if such nondefaulting
Underwriters do not purchase all the Bonds, this Agreement will terminate
without liability to any nondefaulting Underwriter or the Company. In the event
of a default by any Underwriter as set forth in this Section 8, the Closing Date
shall be postponed for such period, not exceeding five Business Days, as the
Representatives shall determine in order to effect whatever changes may thereby
be made necessary in the Registration Statement or the Prospectus or any
amendment or supplement to either thereof, or in any other documents or
arrangements, and the Company agrees to file promptly any amendments or
supplements to the Registration Statement or the Prospectus which in the opinion
of the Representatives may thereby be made necessary. The term "Underwriter" as
used in this Agreement shall include any person substituted under this Section
with like effect as if such person had originally been a party to this
Agreement. Nothing contained in this Agreement shall relieve any defaulting
Underwriter of its liability, if any, to the Company or any nondefaulting
Underwriter for damages occasioned by its default hereunder.

         9.       Termination. This Agreement shall be subject to termination in
the absolute discretion of the Representatives, by notice given to the Company
prior to delivery of and payment

                                       17


for the Bonds, if at any time after the date hereof and prior to the delivery of
and payment for the Bonds (i) trading in the common stock of Xcel Energy Inc.
shall have been suspended by the Commission or the New York Stock Exchange or
trading in securities generally on the New York Stock Exchange shall have been
suspended or limited or minimum prices shall have been established on such
Exchange; (ii) a banking moratorium shall have been declared either by Federal
or New York State authorities; (iii) there shall have occurred a material
disruption in commercial banking or securities settlement or clearance services
in the United States or Europe; or (iv) there shall have occurred any outbreak
or escalation of hostilities, declaration by the United States of a national
emergency or war or other calamity or crisis the effect of which on financial
markets is such as to make it, in the sole judgment of the Representatives,
impracticable or inadvisable to proceed with the offering or delivery of the
Bonds as contemplated by the Prospectus.

         10.      Indemnities to Survive. The respective agreements,
representations, warranties, indemnities and other statements of the Company or
its officers and of the Underwriters set forth in or made pursuant to this
Agreement will remain in full force and effect, regardless of any investigation
made by or on behalf of the Underwriters or the Company or any of the officers,
directors or controlling persons referred to in Section 7 hereof, and will
survive delivery of and payment for the Bonds. The provisions of Sections 6 and
7 hereof shall survive the termination or cancellation of this Agreement.

         11.      Notices. All communications hereunder will be in writing and
effective only on receipt, and, if sent to the Representatives, will be mailed,
delivered or telefaxed to Banc One Capital Markets, Inc., at fax no. (312)
732-4773, and confirmed to Banc One Capital Markets, Inc., 1 Bank One Plaza,
Suite IL1 0595, 8th Floor, Chicago, Illinois 60670, Attention: Structuring &
Execution, and to McDonald Investments Inc., 800 Superior Avenue, Cleveland,
Ohio 44114, and to UBS Securities LLC, at fax no. (203) 719-0495, and confirmed
to UBS Securities LLC, 677 Washington Blvd., Stamford, Connecticut 06901,
Attention: Fixed Income Syndicate; or, if sent to the Company, will be mailed,
delivered or telefaxed to Public Service Company of Colorado, 1225 17th Street,
Denver, Colorado 80202, Attention: Vice President and Treasurer (fax no.: (612)
215-5445) and confirmed to the General Counsel (fax no.: (612) 215-4501).

         12.      Successors. This Agreement will inure to the benefit of and be
binding upon the parties hereto and their respective successors and the officers
and directors and controlling persons referred to in Section 7 hereof, and no
other person will have any right or obligation hereunder.

         13.      Applicable Law. This Agreement will be governed by and
construed in accordance with the laws of the State of New York applicable to
contracts made and to be performed within the State of New York.

         14.      Counterparts. This Agreement may be executed in one or more
counterparts, each of which shall constitute an original and all of which
together shall constitute one and the same instrument.

         15.      Headings. The section headings used herein are for convenience
only and shall not affect the construction hereof.

         16.      Definitions. The terms which follow, when used in this
Agreement, shall have the meanings indicated.

                                       18


         "Act" shall mean the Securities Act of 1933, as amended, and the rules
and regulations of the Commission promulgated thereunder.

         "Business Day" shall mean any day other than a Saturday, a Sunday or a
legal holiday or a day on which banking institutions or trust companies are
authorized or obligated by law to close in the City of New York.

         "Closing Date" shall have the meaning specified in Section 3 hereof.

         "Commission" shall mean the Securities and Exchange Commission.

         "Exchange Act" shall mean the Securities Exchange Act of 1934, as
amended, and the rules and regulations of the Commission promulgated thereunder.

         "Execution Time" shall mean the date and time that this Agreement is
executed and delivered by the parties hereto.

         "GAAP" shall mean United States generally accepted accounting
principles applied on a consistent basis.

         "Mortgage Supplement" shall mean the Supplemental Indenture, dated as
of September 1, 2003, between the Company and U.S. Bank Trust National
Association, as trustee, supplemental to the PSCO 1939 Mortgage.

         "Trust Indenture Act" shall mean the Trust Indenture Act of 1939, as
amended, and the rules and regulations of the Commission promulgated thereunder.

         17.      Underwriters' Counsel. The Company and the Underwriters
acknowledge that Dewey Ballantine LLP (a) is acting as counsel to the
Underwriters in connection with this Agreement and the transactions contemplated
hereby and (b) has acted, and may continue to act, as counsel to the Company's
parent company, Xcel Energy Inc., and certain of its subsidiaries in connection
with certain regulatory matters, and the Company and the Underwriters consent to
such representation.

                                       19


         If the foregoing is in accordance with your understanding of our
agreement, please sign and return to us the enclosed duplicate hereof, whereupon
this Agreement and your acceptance shall represent a binding agreement between
the Company and the several Underwriters.

                                        Very truly yours,

                                        PUBLIC SERVICE COMPANY OF
                                          COLORADO

                                        By: /s/ Benjamin G. S. Fowke III
                                            -----------------------------
                                        Name: Benjamin G. S. Fowke III
                                        Title: Vice President and Treasurer

The foregoing Agreement is hereby confirmed
and accepted as of the date first above written.

BANC ONE CAPITAL MARKETS, INC.
MCDONALD INVESTMENTS INC.
UBS SECURITIES LLC

For themselves and the other several
Underwriters named in Schedule I to the
foregoing Agreement.

By: UBS SECURITIES LLC

By: /s/ Christopher Forshner
    ----------------------------
Name: Christopher Forshner
Title: Executive Director

By: /s/ Scott Whitney
    ----------------------------
Name: Scott Whitney
Title: Director



                                   SCHEDULE I



                                                                                  Principal Amount     Principal Amount
                                                                                  of 4.375% First       of 5.50% First
                                                                                  Collateral Trust     Collateral Trust
                                                                                   Bonds due 2008       Bonds due 2014
                               Underwriters                                       to be Purchased      to be Purchased
                               ------------                                       ----------------     ----------------
                                                                                                 
Banc One Capital Markets, Inc..................................................   $     80,000,000     $     73,333,334
McDonald Investments Inc.                                                         $     80,000,000     $     73,333,333
UBS Securities LLC ............................................................   $     80,000,000     $     73,333,333
U.S. Bancorp Piper Jaffray Inc.................................................   $     24,000,000     $     22,000,000
Wells Fargo Brokerage Services, LLC............................................   $     24,000,000     $     22,000,000
Citigroup Global Markets, Inc. ................................................   $     12,000,000     $     11,000,000
                                                                                  ----------------     ----------------

                  Total........................................................   $    300,000,000     $    275,000,000



                                                                     EXHIBIT A-1

                      FORM OF OPINION OF ANN E. HOPFENBECK

Ladies and Gentlemen:

                  For the purpose of rendering this opinion, I have examined the
proceedings taken by Public Service Company of Colorado, a Colorado corporation
(the "Company"), with respect to the issue and sale by the Company of $
300,000,000 principal amount of 4.375% First Collateral Trust Bonds, Series No.
14 due 2008 and $ 275,000,000 principal amount of 5.50% First Collateral Trust
Bonds, Series No. 15 due 2014 (collectively, the "Bonds"). In connection
therewith I have participated in the preparation of the proceedings for the
issuance and sale of the Bonds including the Underwriting Agreement dated
September 2, 2003, between you and the Company relating to your purchase of the
Bonds (the "Agreement"), and have either participated in the preparation of or
examined the Trust Indenture dated October 1, 1993, from the Company to U.S.
Bank Trust National Association, as successor trustee (the "Trustee"), as
heretofore supplemented and as it will be further supplemented by Supplemental
Indenture No. 15 creating the Bonds (said indenture, as so supplemented and to
be further supplemented, being hereafter referred to as the "Indenture") and the
PSCo 1939 Mortgage (as defined in the Indenture). This letter is furnished to
the Underwriters pursuant to Section 5(b) of the Agreement. Except as otherwise
defined herein, terms used in this letter that are defined in the Agreement are
used herein as so defined. I also have participated in the preparation of or
examined the registration statement and any amendments thereto and the
accompanying prospectuses and any amendments or supplements thereto, as filed
under the Act, with respect to the Bonds. My examination has extended to all
statutes, records, instruments, and documents which I have deemed necessary to
examine for the purposes of this opinion.

                  I am of the opinion that:

                  1.       The Company has been duly incorporated and is validly
         existing as a corporation in good standing under the laws of the State
         of Colorado with corporate power and authority to own, lease and
         operate its properties and conduct its business as described in the
         Prospectus and to enter into and perform its obligations under the
         Agreement;

                  2.       The Agreement has been duly authorized, executed and
         delivered by the Company;

                  3.       The issuance and sale of the Bonds, and the issuance
         and delivery of the Class A Bonds, have been duly authorized and
         approved by an order of The Public Utilities Commission of the State of
         Colorado and such order is final and in full force and effect on the
         date hereof, the time for appeal therefrom or review thereof or
         intervention with respect thereto having expired; no further approval,
         authorization, consent or other order of any public board or body in
         the State of Colorado is legally required in connection with the
         transactions contemplated by the Agreement, the Indenture or the PSCo
         1939 Mortgage, except as may be required under the blue sky laws of any
         jurisdiction in connection with the purchase and distribution of the
         Bonds by the Underwriters in the manner contemplated by the Agreement
         and in the Prospectus;

                                      A-1-1


                  4.       Neither the execution and delivery of the Agreement,
         the issue and sale of the Bonds, nor the consummation of any other of
         the transactions therein contemplated, nor the fulfillment of the terms
         thereof will conflict with, result in a breach or violation or
         imposition of any lien, charge or encumbrance upon any property or
         assets of the Company or any of its subsidiaries, other than the
         security interest created by the Bonds, the Indenture and the PSCo 1939
         Mortgage, under (i) the Restated Articles of Incorporation, as amended,
         or By-Laws of the Company or any of its subsidiaries; (ii) the terms of
         any indenture, contract, lease, mortgage, deed of trust, note
         agreement, loan agreement or other agreement, obligation, condition,
         covenant or instrument to which the Company or any of its subsidiaries
         is a party or bound or to which its or their property is subject; or
         (iii) any statute, law, rule, regulation, judgment, order or decree
         applicable to the Company or any of its subsidiaries of any court,
         regulatory body, administrative agency, governmental body, arbitrator
         or other authority having jurisdiction over the Company or any of its
         subsidiaries or any of its or their properties except, in the case of
         clause (ii) or (iii), any such conflict, breach or violation, if it did
         exist, would not, individually or in the aggregate, have a material
         adverse change in the condition (financial or otherwise), prospects,
         earnings, business or properties of the Company and its subsidiaries
         taken as a whole, whether or not arising from transactions in the
         ordinary course of business;

                  5.       The facsimile signature of a Senior Vice President or
         Vice President of the Company in lieu of his manual signature on the
         Bonds and the Class A Bonds and the facsimile signature of the
         Secretary or an Assistant Secretary of the Company attesting the
         corporate seal in lieu of his manual signature on the Bonds and the
         Class A Bonds have been duly and properly authorized by the Board of
         Directors of the Company, are not inconsistent with the provisions of
         the Restated Articles of Incorporation, as amended, or By-Laws of the
         Company and are valid and effective under the laws of the State of
         Colorado; and the facsimile signatures of such officers on the Bonds
         and the Class A Bonds have the same legal effect as though they had
         manually signed and attested the Bonds and the Class A Bonds as such
         respective officers;

                  6.       The descriptions in the Registration Statement and
         Prospectus of Colorado state statutes and legal and governmental
         proceedings are accurate in all material respects; to the best of my
         knowledge, there are no franchises, contracts, indentures, mortgages,
         loan agreements, notes, leases or other instruments that would be
         required to be described in the documents incorporated by reference in
         the Prospects that are not described or referred to in such
         incorporated documents, and the descriptions thereof or references
         thereto are correct in all material respects;

                  7.       There is no pending, or to my knowledge, threatened
         suit or proceeding before any court or governmental agency, authority
         or body or any arbitration involving the Company or any of its
         subsidiaries required to be disclosed in the Prospectus which is not
         adequately disclosed in the Prospectus; and

                  8.       The franchises held by the Company, together with the
         applicable Certificates of Convenience and Necessity issued by The
         Public Utilities Commission of the State of Colorado, give the Company
         all necessary authority for the maintenance and operation of its
         properties and business as now conducted, and are free from burdensome
         restrictions or conditions of an unusual character.

                  In the course of my participation in the preparation or
examination of the Registration Statement and any amendments thereto and the
Prospectus and any amendments or supplements thereto

                                      A-1-2


I made investigations as to the accuracy of certain of the statements of fact
contained therein, I discussed other matters with officers, employees, and
representatives of the Company, and I examined various corporate records and
data. While I do not pass upon or assume responsibility for, and shall not be
deemed to have independently verified, the accuracy and completeness of the
statements contained in the Registration Statement or the Prospectus (except as
to matters set forth in paragraphs 6 and 7 above), nothing has come to my
attention that would lead me to believe that the Registration Statement, at the
time it became effective, contained an untrue statement of a material fact or
omitted to state a material fact required to be stated therein or necessary in
order to make the statements therein, not misleading, or that the Prospectus, at
the time it was filed with the Commission pursuant to Rule 424(b) under the Act
and at the date hereof, contained or contains an untrue statement of material
fact or omitted or omits to state a material fact necessary in order to make the
statements therein, in light of the circumstances under which they were made,
not misleading.

                  My opinions herein are limited to the laws of the State of
Colorado. For purposes of rendering their opinion of even date herewith to the
Underwriters, Dewey Ballantine LLP are entitled to rely on my opinions in
paragraphs 1, 2 and 3 above as to all matters of Colorado law as if such
opinions were addressed to them.

                                        Respectfully submitted,

                                        By: ____________________________________
                                            Ann E. Hopfenbeck
                                            Assistant General Counsel
                                            Xcel Energy Services, Inc.

                                      A-1-3


                                                                     EXHIBIT A-2

                          FORM OF OPINION OF JONES DAY

Ladies and Gentlemen:

                  We have acted as special counsel to Public Service Company of
Colorado, a Colorado corporation (the "Company"), in connection with the sale by
the Company pursuant to the Underwriting Agreement, dated as of September 2,
2003 (the "Agreement"), by and among the Company and the Underwriters named on
Schedule I thereto (the "Underwriters"), for whom you are acting as
representatives (the "Representatives"), of $300,000,000 aggregate principal
amount of 4.375% First Collateral Trust Bonds, Series 14 due 2008, and
$275,000,000 aggregate principal amount of 5.50% First Collateral Trust Bonds,
Series 15 due 2014 of the Company (collectively, the "Bonds") being issued on
this date under the Company's Indenture, dated as of October 1, 1993, to U.S.
Bank Trust National Association, as successor trustee (the "Trustee"), as
heretofore supplemented and as it is being further supplemented by a
supplemental indenture creating the Bonds (said Indenture, as so supplemented,
being hereafter referred to as the "Indenture"). This letter is furnished to the
Underwriters pursuant to Section 5(b) of the Agreement. Except as otherwise
defined herein, terms used in this letter that are defined in the Agreement are
used herein as so defined.

                  In connection with the opinions expressed herein, we have
examined such documents and records, including an examination of originals or
copies certified or otherwise identified to our satisfaction, and matters of law
as we have deemed necessary for purposes of this opinion. Based upon the
foregoing and subject to the further assumptions, qualifications and limitations
stated herein, we are of the opinion that:

                  1.       Assuming that the Agreement has been duly (a)
         authorized by the Company and (b) executed and delivered by the Company
         under Colorado law, the Agreement has been duly executed and delivered
         by the Company to the extent such execution and delivery are questions
         of New York law.

                  2.       The Company is not, and after giving effect to the
         offering and sale of the Bonds and the application of the proceeds
         thereof as described in the Prospectus will not be, an "investment
         company" or an entity "controlled" by an "investment company" within
         the meaning of the Investment Company Act of 1940, as amended, without
         taking account of any exemption arising out of the number of holders of
         the Company's securities.

                  3.       Assuming that the issuance and sale of the Bonds, and
         the issuance and delivery of the Class A Bonds, have been duly
         authorized and approved by an order of The Public Utilities Commission
         of the State of Colorado and such order is final and in full force and
         effect on the date hereof, and that the time for appeal therefrom or
         review thereof or intervention with respect thereto have expired, no
         approval, authorization, consent or order of any public board or body
         under the laws of the United States of America is legally required in
         connection with the transactions contemplated by the Agreement, the
         Indenture or the PSCo 1939 Mortgage, except those that already have
         been obtained and are in full force and effect.

                                      A-2-1


                  4.       The Registration Statement has been declared
         effective by the Commission under the Act, the Prospectus has been
         filed with the Commission pursuant to Rule 424(b) under the Act in the
         manner and within the time period required by Rule 424(b) under the
         Act; and no stop order suspending the effectiveness of the Registration
         Statement has been issued under the Act and, to the best of our
         knowledge, no proceedings for that purpose have been instituted or are
         pending or are threatened by the Commission;

                  5.       Except as to the financial statements or other
         financial or statistical data included or incorporated by reference
         therein, as to which we express no opinion, the Registration Statement,
         at the time it became effective, and the Prospectus, at the time it was
         filed with the Commission pursuant to Rule 424(b), complied as to form
         in all material respects with the applicable requirements of the Act
         and the Trust Indenture Act.

                  6.       Except as to the financial statements or other
         financial or statistical data included or incorporated by reference
         therein, as to which we express no opinion, the documents incorporated
         by reference in the Prospectus, when they were filed with the
         Commission, compiled as to form in all material respects with the
         applicable requirements of the Exchange Act.

                  7.       The descriptions in the Registration Statement and
         the Prospectus of United States federal statutes are accurate and
         fairly present the information purported to be given.

                  We have not independently verified and are not passing upon,
and do not assume any responsibility for, the accuracy, completeness or
fairness, except and to the extent as set forth in paragraph 8 above, of the
information included in the Registration Statement or Prospectus. We have
participated in the preparation of the Registration Statement and Prospectus.
From time to time in connection therewith, we have had discussions with
officers, directors and employees of the Company and Xcel Energy Inc., a
Minnesota corporation and the parent corporation of the Company, with
representatives of Deloitte & Touche LLP, the independent accountants who
examined certain of the financial statements of the Company, and with the
Underwriters and counsel to the Underwriters. Based upon our participation and
discussions described above, nothing has come to our attention that would lead
us to believe that the Registration Statement, at the time it became effective,
contained an untrue statement of a material fact or omitted to state a material
fact required to be stated therein or necessary in order to make the statements
therein, not misleading, or that the Prospectus, at the time it was filed with
the Commission pursuant to Rule 424(b) under the Act and at the date hereof,
contained or contains an untrue statement of material fact or omitted or omits
to state a material fact necessary in order to make the statements therein, in
light of the circumstances under which they were made, not misleading (except
that we express no view as to the financial statements, financial schedules and
other financial data included or incorporated by reference in the Prospectus).

                  The opinions and views set forth above are subject to the
following assumptions, qualifications and limitations:

                  We have assumed, for purposes of the opinions and views
expressed herein, the legal capacity of all natural persons executing documents,
the genuineness of all signatures, the authenticity of original and certified
documents and the conformity to original or certified copies of all copies
submitted to us as conformed or reproduction copies. For the purposes of the
opinions and views expressed herein, we also have assumed that each of the
Underwriters and the Trustee has duly authorized, executed and delivered the
documents to which each of them is a party and that each of

                                      A-2-2


such documents is the valid, binding and enforceable obligation of each of the
Underwriters and the Trustee, respectively.

                  Our examination of matters of law in connection with the
opinions expressed herein have been limited to, and accordingly our opinions
herein are limited to, the federal laws of the United States of America and the
laws of the State of New York, in each case as currently in effect. In
connection with our opinions set forth herein, we express no opinion as to any
matters of, or that relate to, the laws of any other jurisdiction, including the
laws of the State of Colorado. To the extent such opinions relate to any
provision of Colorado law, we direct you to the opinion dated the date hereof of
Ann E. Hopfenbeck, Esq., Assistant General Counsel of Xcel Energy Services, Inc.
and a member of the Colorado bar, which opinion previously has been delivered to
you.

                  It should be understood that the scope of our representation
does not include providing legal services to any financial institution or
financial institution-affiliated party with regard to any matter (a "financial
institutions regulatory matter") the resolution of which requires reference to
any provision of Title 12 of the United States Code as in effect from time to
time, the policies, procedures, guidelines or practices of any state regulator
with respect to any such federal or state law or regulation, or any other
federal or state law or regulation or regulatory policy, procedure or practice
expressly applicable to financial institutions or, in their capacities as such,
financial institution-affiliated parties or, if not expressly applicable, then
to the extent applicable by implication or actually applied to a financial
institution or financial institution-affiliated party. We express no opinion
regarding the compliance by any Underwriter with any such financial institutions
regulatory matter.

                  This letter is furnished by us, as special counsel to the
Company, to you, as the Representatives, solely for the benefit of the
Underwriters and solely with respect to the purchase of the Bonds from the
Company by the Underwriters upon the understanding that we are not hereby
assuming any professional responsibility to any other person whatsoever, and
that this letter is not to be used, circulated, quoted or otherwise referred to
for any other purpose.

                                        Very truly yours,

                                      A-2-3


                                                                     EXHIBIT A-3

            FORM OF OPINION OF LEBOEUF, LAMB, GREENE & MACRAE, L.L.P.

Ladies and Gentlemen:

                  We have acted as counsel to Public Service Company of Colorado
(the "Company"), with respect to matters relating to the Indenture dated as of
December 31, 1939 (the "1939 PSCo Mortgage") between the Company and U.S. Bank
Trust National Association (formerly First Trust of New York, National
Association), as successor trustee (the "1939 Trustee"), and the Indenture dated
as of October 1, 1993, as amended and supplemented (the "Indenture"), between
the Company and U.S. Bank Trust National Association (formerly First Trust of
New York, National Association), as successor trustee (the "Trustee") in
connection with the sale by the Company of $300,000,000 aggregate principal
amount of its First Collateral Trust Bonds, Series No. 14 due 2008 and
$275,000,000 aggregate principal amount of its First Collateral Trust Bonds,
Series No. 15 due 2014 (collectively, the "Bonds") on the basis of an equivalent
amount of Class A Bonds (as defined in the Indenture). This opinion is being
delivered pursuant to Section 5(b) of the Underwriting Agreement, dated
September 2, 2003 (the "Agreement"), between the Company and you as
representatives of the Underwriters (the "Representatives"). Unless otherwise
stated, defined terms used herein shall have the respective meanings given to
them in the Agreement.

                  We are not general counsel to the Company and our
representation of the Company consists of advising it with respect to corporate
and regulatory matters as to which we have been specifically consulted. We are
familiar with the legal matters pertaining to, and the corporate proceedings of
the Company taken with respect to, the authorization and the issuance and sale
by the Company of the Bonds and the authorization and the issuance and delivery
by the Company of the Class A Bonds. We have examined, among other things, the
Registration Statement and Prospectus and any amendment and supplement thereto,
the corporate records of the Company, the Indenture (including the Supplemental
Indenture creating the Bonds), the PSCo 1939 Mortgage (including the
supplemental indenture thereto under which the Class A Bonds are being issued),
and such other proceedings, papers and documents as we have deemed relevant for
the purposes of rendering the opinions enumerated below. In such examination, we
have assumed the genuineness of all signatures, the authenticity of all
documents submitted to us as originals, the conformity to the original documents
of all documents submitted to us as copies and the authenticity of all such
latter documents. We have relied as to various questions of fact upon
discussions with officers and representatives of the Company and the
representations and warranties of the Company contained in the Agreement and
upon the certificates of public officials and of officers of the Company being
delivered to you thereunder. With respect to the opinions expressed in
paragraphs 5, 6 and 7 below, we have relied upon information obtained from
public records and from the Company.

                  On the basis of and subject to the foregoing, and subject to
the further limitations and qualifications set forth below, it is our opinion
that:

                  1.       The Indenture has been duly and validly authorized,
         executed and delivered by the Company and is in due and proper form and
         (assuming the Indenture has been duly authorized, executed and
         delivered by the Trustee) constitutes a legal, valid and binding

                                      A-2-1


         mortgage of the Company, enforceable in accordance with its terms,
         subject to bankruptcy, insolvency, moratorium, fraudulent conveyance
         and transfer, and other similar laws affecting the rights of mortgagees
         and creditors generally, state laws which affect the enforcement of
         certain remedial provisions of the Indenture, and general principles of
         equity (regardless of whether such principles are considered in a
         proceeding at law or in equity); provided, however, that such state
         laws which affect the enforcement of certain remedial provisions of the
         Indenture will not, in our opinion, render the remedies afforded by the
         Indenture inadequate for the practical realization of the benefit of
         the security provided thereby;

                  2.       The Bonds are in due and proper form and the issuance
         and sale of the Bonds have been duly authorized by all necessary
         corporate action, and when duly executed, authenticated and delivered
         to the Underwriters pursuant to the Agreement against payment of the
         consideration set forth therein, the Bonds will be legal, valid and
         binding obligations of the Company enforceable (subject to the
         exceptions and limitations referred to in paragraph 1 hereof) in
         accordance with their terms and entitled to the benefits and security
         of the Indenture; and the Bonds will be secured equally and ratably
         with all other bonds outstanding under the Indenture;

                  3.       The PSCo 1939 Mortgage has been duly and validly
         authorized, executed and delivered by the Company and is in due and
         proper form and (assuming the PSCo 1939 Mortgage has been duly
         authorized, executed and delivered by the 1939 Trustee) constitutes a
         legal, valid and binding mortgage of the Company, enforceable in
         accordance with its terms, subject to bankruptcy, insolvency,
         moratorium, fraudulent conveyance and transfer, and other similar laws
         affecting the rights of mortgagees and creditors generally, state laws
         which affect the enforcement of certain remedial provisions of the PSCo
         1939 Mortgage and general principles of equity (regardless of whether
         such principles are considered in a proceeding at law or in equity);
         provided, however, that such state laws which affect the enforcement of
         certain remedial provisions of the Indenture will not, in our opinion,
         render the remedies afforded by the PSCo 1939 Mortgage inadequate for
         the practical realization of the benefit of the security provided
         thereby;

                  4.       The Class A Bonds are in due and proper form and the
         issuance and delivery of the Class A Bonds have been duly authorized by
         all necessary corporate action; and when (a) the Class A Bonds have
         been duly executed, authenticated and delivered to the Trustee pursuant
         to the PSCo 1939 Mortgage and (b) the Bonds have been duly executed,
         authenticated and delivered to the Underwriters pursuant to the
         Agreement against payment of the consideration set forth therein, the
         Class A Bonds will be legal, valid and binding obligations of the
         Company enforceable (subject to the exceptions and limitations referred
         to in paragraph 3 hereof) in accordance with their terms and entitled
         to the benefits and security of the PSCo 1939 Mortgage; and the Class A
         Bonds will be secured equally and ratably with all other bonds
         outstanding under the PSCo 1939 Mortgage (except to the extent that any
         sinking, amortization, improvement or other fund may afford additional
         security for such bonds of any particular series);

                  5.       The Company has good title to the real properties
         specifically or generally described or referred to in the Indenture and
         in the PSCo 1939 Mortgage as subject to the respective liens thereof
         (except such real property as may have been sold, exchanged or
         otherwise disposed of), subject only to (a) in the case of all such
         properties, the lien of the PSCo 1939 Mortgage and "permitted
         encumbrances" (as defined in the PSCo 1939 Mortgage) and (b)

                                      A-2-2


         in the case of such properties which are used or to be used in or in
         connection with the Electric Utility Business (as defined in the
         Indenture) (whether or not such use is the sole use of such property),
         the lien of the Indenture and Permitted Liens (as defined in the
         Indenture);

                  6.       The Indenture and the filings and recordations made
         in connection therewith constitute a mortgage lien on the properties
         specifically or generally described or referred to therein as subject
         to the lien thereof (except such properties as may have been sold,
         exchanged or otherwise disposed of or released from the lien thereof in
         accordance with the terms thereof), subject to no liens prior to the
         lien of the Indenture other than Permitted Liens and the lien of the
         PSCo 1939 Mortgage; and the Indenture by its terms effectively subjects
         to the lien thereof all property (except property of the kinds
         specifically excepted from the lien of the Indenture by the terms
         thereof) acquired by the Company after the date of execution and
         delivery of the Indenture and used or to be used in or in connection
         with the Electric Utility Business, subject to Permitted Liens, the
         lien of the PSCo 1939 Mortgage, any lien thereon existing at the time
         of such acquisition and to any liens for unpaid portions of the
         purchase money placed thereon at the time of such acquisition, and also
         subject to the provisions of Article Thirteen of the Indenture and to
         certain possible claims of a trustee in bankruptcy and possible claims
         and taxes of the federal government;

                  7.       The PSCo 1939 Mortgage and the filings and
         recordations made in connection therewith constitute a first mortgage
         lien on the properties specifically or generally described or referred
         to therein as subject to the lien thereof (except such property as may
         have been sold, exchanged or otherwise disposed of or released from the
         lien thereof in accordance with the terms thereof), and, with respect
         to the shares of stock pledged thereunder, the PSCo 1939 Mortgage and
         the possession by the Trustee of such stock and appropriate stock
         powers in the State of New York pursuant to the PSCo 1939 Mortgage is
         sufficient to create a security interest under Article 9 of the Uniform
         Commercial Code as in effect in the State of New York with respect to
         such stock (except such stock as may have been sold, exchanged or
         otherwise disposed of or released from the lien thereof in accordance
         with the terms thereof), subject to no liens or security interests
         prior to the lien and security interest created by the PSCo 1939
         Mortgage other than "permitted encumbrances"; and the PSCo 1939
         Mortgage by its terms effectively subjects to the lien or security
         interest thereof all property (except property of the kinds
         specifically excepted from the lien of the PSCo 1939 Mortgage by the
         terms thereof) acquired by the Company after the date of execution and
         delivery of the PSCo 1939 Mortgage, subject to "permitted
         encumbrances", to any lien thereon existing at the time of such
         acquisition and to any liens for unpaid portions of the purchase money
         placed thereon at the time of acquisition and also subject to the
         provisions of Article XI of the PSCo 1939 Mortgage and to certain
         possible claims of a trustee in bankruptcy and possible claims and
         taxes of the federal government; and

                  8.       The Bonds, the Indenture, the Class A Bonds, and the
         PSCo 1939 Mortgage conform as to legal matters to the descriptions of
         the terms thereof contained in the Prospectus under the captions
         "Supplemental Description of the First Collateral Trust Bonds,"
         "Description of the First Collateral Trust Bonds" and "Description of
         the 1939 Mortgage".

                  This opinion is limited to the laws of the State of New York
and the State of Colorado and the federal law of the United States of America.
This opinion speaks as of the date hereof and we undertake no responsibility to
advise you of any change in circumstances after the date hereof.

                                      A-2-3


                  Dewey Ballantine LLP is hereby authorized to rely upon
paragraphs 1, 2, 3, 4 and 8 of this letter as to matters governed by the law of
the State of Colorado as if this letter, solely with respect to aforementioned
paragraphs, were addressed to them.

                  This letter is not being delivered for the benefit of, nor may
it be relied upon by, the holders of the Bonds or any other party to which it is
not specifically addressed or to which reliance has not expressly been permitted
hereby. This letter may be relied upon only by the addressees hereof in
connection with the issuance and sale of the Bonds and may not be relied upon
for any other purpose.

                                        Very truly yours,

                                      A-2-4


                                                                       EXHIBIT B

                     FORM OF LETTER OF DELOITTE & TOUCHE LLP

                                      A-3-1

EX-4.01

                             SUPPLEMENTAL INDENTURE

                         (DATED AS OF SEPTEMBER 1, 2003)

                                 --------------

                       PUBLIC SERVICE COMPANY OF COLORADO

                                       TO

                      U.S. BANK TRUST NATIONAL ASSOCIATION,
                                                       AS TRUSTEE

                                 --------------

                  CREATING TWO ISSUES OF FIRST MORTGAGE BONDS,
                   COLLATERAL SERIES N AND COLLATERAL SERIES O

                                 --------------

      (SUPPLEMENTAL TO INDENTURE DATED AS OF DECEMBER 1, 1939, AS AMENDED)



                  SUPPLEMENTAL INDENTURE, dated as of September 1, 2003, between
PUBLIC SERVICE COMPANY OF COLORADO, a corporation organized and existing under
the laws of the State of Colorado (the "Company"), party of the first part, and
U.S. BANK TRUST NATIONAL ASSOCIATION (FORMERLY FIRST TRUST OF NEW YORK, NATIONAL
ASSOCIATION), a national banking association, as successor trustee (the
"Trustee") to Morgan Guaranty Trust Company of New York (formerly Guaranty Trust
Company of New York), party of the second part.

                  WHEREAS, the Company heretofore executed and delivered to the
Trustee its Indenture, dated as of December 1, 1939 (the "Principal Indenture"),
to secure its First Mortgage Bonds from time to time issued thereunder; and

                  WHEREAS, the Company has heretofore executed and delivered to
the Trustee the Supplemental Indentures referred to in Schedule A hereto for
certain purposes, including the creation of series of bonds, the subjection to
the lien of the Principal Indenture of property acquired after the execution and
delivery thereof, the amendment of certain provisions of the Principal Indenture
and the appointment of the successor Trustee; and

                  WHEREAS, the Principal Indenture as supplemented and amended
by all Supplemental Indentures heretofore executed by the Company and the
Trustee is hereinafter referred to as the "Indenture", and, unless the context
requires otherwise, references herein to Articles and Sections of the Indenture
shall be to Articles and Sections of the Principal Indenture as so amended; and

                  WHEREAS, the Company proposes to create two new series of
First Mortgage Bonds to be designated as First Mortgage Bonds, Collateral Series
N (the "Collateral Series N Bonds") and First Mortgage Bonds, Collateral Series
O (the "Collateral Series O Bonds"), to be issued and delivered to the trustee
under the 1993 Mortgage (as hereinafter defined) as the basis for the
authentication and delivery under the 1993 Mortgage of First Collateral Trust
Bonds, Series No. 14 and First Collateral Trust Bonds, Series No. 15,
respectively, all as hereinafter provided, and to vary in certain respects the
covenants and provisions contained in Article V of the Indenture, to the extent
that such covenants and provisions apply to the Collateral Series N Bonds and
the Collateral Series O Bonds; and

                  WHEREAS, the Company, pursuant to the provisions of the
Indenture, has, by appropriate corporate action, duly resolved and determined to
execute this Supplemental Indenture for the purpose of providing for the
creation of the Collateral Series N Bonds and the Collateral Series O Bonds and
of specifying the form, provisions and particulars thereof, as in the Indenture
provided or permitted and of giving to the Collateral Series N Bonds and the
Collateral Series O Bonds the protection and security of the Indenture; and

                  WHEREAS, the Company represents that all acts and proceedings
required by law and by the charter and by-laws of the Company, including all
action requisite on the part of its shareholders, directors and officers,
necessary to make the Collateral Series N Bonds and the Collateral Series O
Bonds , when executed by the Company, authenticated and delivered by the Trustee
and duly issued, the valid, binding and legal obligations of the Company, and to
constitute the Principal Indenture and all indentures supplemental thereto,
including this

                                       1



Supplemental Indenture, valid, binding and legal instruments for the security of
the bonds of all series, including the Collateral Series N Bonds and the
Collateral Series O Bonds , in accordance with the terms of such bonds and such
instruments, have been done, performed and fulfilled, and the execution and
delivery hereof have been in all respects duly authorized;

                  NOW, THEREFORE, THIS SUPPLEMENTAL INDENTURE WITNESSETH:

                  That Public Service Company of Colorado, the Company named in
the Indenture, in consideration of the premises and of One Dollar to it duly
paid by the Trustee at or before the ensealing and delivery of these presents,
the receipt whereof is hereby acknowledged, and in pursuance of the direction
and authority of the Board of Directors of the Company given at a meeting
thereof duly called and held, and in order to create the Collateral Series N
Bonds and the Collateral Series O Bonds and to specify the form, terms and
provisions thereof, and to secure the payment of the principal of and premium,
if any, and interest, if any, on all bonds from time to time outstanding under
the Indenture, including the Collateral Series N Bonds and the Collateral Series
O Bonds, according to the terms of said bonds, and to secure the performance and
observance of all of the covenants and conditions contained in the Indenture,
has executed and delivered this Supplemental Indenture and has granted,
bargained, sold, warranted, aliened, remised, released, conveyed, assigned,
transferred, mortgaged, pledged, set over and confirmed unto U.S. Bank Trust
National Association, as Trustee, and its successor or successors in the trust
and its and their assigns forever;

                  TO HAVE AND TO HOLD all and singular the properties, rights,
privileges and franchises described in the Principal Indenture and in the
several Supplemental Indentures hereinabove referred to and owned by the Company
on the date of the execution and delivery hereof (other than property of a
character expressly excepted from the lien of the Indenture as therein set
forth) unto the Trustee and its successor or successors and assigns forever;

                  SUBJECT, HOWEVER, to permitted encumbrances as defined in the
Indenture;

                  IN TRUST, NEVERTHELESS, upon the terms and trusts set forth in
the Indenture, for the equal and proportionate benefit and security of all
present and future holders of the bonds and coupons issued and to be issued
under the Indenture, including the Collateral Series N Bonds and the Collateral
Series O Bonds, without preference, priority or distinction as to lien (except
as any sinking, amortization, improvement or other fund established in
accordance with the provisions of the Indenture or any indenture supplemental
thereto may afford additional security for the bonds of any particular series)
of any of said bonds over any others thereof by reason of series, priority in
the time of the issue or negotiation thereof, or otherwise howsoever, except as
provided in Section 2 of Article IV of the Indenture.

                                  ARTICLE ONE

            CREATION AND DESCRIPTION OF THE COLLATERAL SERIES N BONDS

                  SECTION 1. A new series of bonds to be issued under and
secured by the Indenture is hereby created, the bonds of such new series to be
designated First Mortgage Bonds, Collateral Series N. The Collateral Series N
Bonds shall be limited to an aggregate principal

                                       2



amount of Three Hundred Million dollars ($300,000,000). The Collateral Series N
Bonds shall mature on October 1, 2008. The Collateral Series N Bonds shall not
bear interest.

                  The principal of each of the Collateral Series N Bonds shall
be payable, upon presentation thereof, at the office or agency of the Company in
the city in which the principal corporate trust office of the 1993 Mortgage
Trustee (as hereinafter defined) is located, in any coin or currency of the
United States of America which at the time of payment shall be legal tender for
the payment of public and private debts.

                  The Collateral Series N Bonds shall be issued and delivered by
the Company to U.S. Bank Trust National Association, as successor trustee under
the Indenture, dated as of October 1, 1993, as supplemented (the "1993
Mortgage"), of the Company to such successor trustee (the "1993 Mortgage
Trustee"), as the basis for the authentication and delivery under the 1993
Mortgage of First Collateral Trust Bonds, Series No. 14. As provided in the 1993
Mortgage, the Collateral Series N Bonds will be registered in the name of the
1993 Mortgage Trustee or its nominee and will be owned and held by the 1993
Mortgage Trustee, subject to the provisions of the 1993 Mortgage, for the
benefit of the holders of all securities from time to time outstanding under the
1993 Mortgage, and the Company shall have no interest therein.

                  Any payment by the Company under the 1993 Mortgage of the
principal of the securities which shall have been authenticated and delivered
under the 1993 Mortgage on the basis of the issuance and delivery to the 1993
Mortgage Trustee of Collateral Series N Bonds (other than by the application of
the proceeds of a payment in respect of such Collateral Series N Bonds), shall,
to the extent thereof, be deemed to satisfy and discharge the obligation of the
Company, if any, to make a payment of principal of such Collateral Series N
Bonds which is then due.

                  The Trustee may conclusively presume that the obligation of
the Company to pay the principal of the Collateral Series N Bonds as the same
shall become due and payable shall have been fully satisfied and discharged
unless and until it shall have received a written notice from the 1993 Mortgage
Trustee, signed by an authorized officer thereof, stating that the principal of
specified Collateral Series N Bonds has become due and payable and has not been
fully paid, and specifying the amount of funds required to make such payment.

                  Each Collateral Series N Bond shall be dated as of the date of
its authentication.

                  The Collateral Series N Bonds shall be issued as fully
registered bonds only, in denominations of $1,000 and multiples thereof.

                  The Collateral Series N Bonds shall be registerable and
exchangeable at the office or agency of the Company in the city in which the
principal corporate trust office of the 1993 Mortgage Trustee is located, in the
manner and upon the terms set forth in Section 5 of Article II of the Indenture;
provided, however, that none of the Collateral Series N Bonds shall be
transferable except to a successor trustee under the 1993 Mortgage. No service
charge shall be made for any exchange or transfer of any Collateral Series N
Bond.

                  SECTION 2. The text of the Collateral Series N Bonds shall be
substantially in the form attached hereto as Exhibit A.

                                       3



                  SECTION 3. The Collateral Series N Bonds may be executed by
the Company and delivered to the Trustee and, upon compliance with all
applicable provisions and requirements of the Indenture in respect thereof,
shall be authenticated by the Trustee and delivered (without awaiting the filing
or recording of this Supplemental Indenture) in accordance with the written
order or orders of the Company.

                                  ARTICLE TWO

            CREATION AND DESCRIPTION OF THE COLLATERAL SERIES O BONDS

                  SECTION 1. A new series of bonds to be issued under and
secured by the Indenture is hereby created, the bonds of such new series to be
designated First Mortgage Bonds, Collateral Series O. The Collateral Series O
Bonds shall be limited to an aggregate principal amount of Two Hundred
Seventy-Five Million dollars ($275,000,000). The Collateral Series O Bonds shall
mature on April 1, 2014. The Collateral Series O Bonds shall not bear interest.

                  The principal of each of the Collateral Series O Bonds shall
be payable, upon presentation thereof, at the office or agency of the Company in
the city in which the principal corporate trust office of the 1993 Mortgage
Trustee is located, in any coin or currency of the United States of America
which at the time of payment shall be legal tender for the payment of public and
private debts.

                  The Collateral Series O Bonds shall be issued and delivered by
the Company to the 1993 Mortgage Trustee, as the basis for the authentication
and delivery under the 1993 Mortgage of First Collateral Trust Bonds, Series No.
15. As provided in the 1993 Mortgage, the Collateral Series O Bonds will be
registered in the name of the 1993 Mortgage Trustee or its nominee and will be
owned and held by the 1993 Mortgage Trustee, subject to the provisions of the
1993 Mortgage, for the benefit of the holders of all securities from time to
time outstanding under the 1993 Mortgage, and the Company shall have no interest
therein.

                  Any payment by the Company under the 1993 Mortgage of the
principal of the securities which shall have been authenticated and delivered
under the 1993 Mortgage on the basis of the issuance and delivery to the 1993
Mortgage Trustee of Collateral Series O Bonds (other than by the application of
the proceeds of a payment in respect of such Collateral Series O Bonds), shall,
to the extent thereof, be deemed to satisfy and discharge the obligation of the
Company, if any, to make a payment of principal of such Collateral Series O
Bonds which is then due.

                  The Trustee may conclusively presume that the obligation of
the Company to pay the principal of the Collateral Series O Bonds as the same
shall become due and payable shall have been fully satisfied and discharged
unless and until it shall have received a written notice from the 1993 Mortgage
Trustee, signed by an authorized officer thereof, stating that the principal of
specified Collateral Series O Bonds has become due and payable and has not been
fully paid, and specifying the amount of funds required to make such payment.

                  Each Collateral Series O Bond shall be dated as of the date of
its authentication.

                                       4



                  The Collateral Series O Bonds shall be issued as fully
registered bonds only, in denominations of $1,000 and multiples thereof.

                  The Collateral Series O Bonds shall be registerable and
exchangeable at the office or agency of the Company in the city in which the
principal corporate trust office of the 1993 Mortgage Trustee is located, in the
manner and upon the terms set forth in Section 5 of Article II of the Indenture;
provided, however, that none of the Collateral Series O Bonds shall be
transferable except to a successor trustee under the 1993 Mortgage. No service
charge shall be made for any exchange or transfer of any Collateral Series O
Bond.

                  SECTION 2. The text of the Collateral Series O Bonds shall be
substantially in the form attached hereto as Exhibit B.

                  SECTION 3. The Collateral Series O Bonds may be executed by
the Company and delivered to the Trustee and, upon compliance with all
applicable provisions and requirements of the Indenture in respect thereof,
shall be authenticated by the Trustee and delivered (without awaiting the filing
or recording of this Supplemental Indenture) in accordance with the written
order or orders of the Company.

                                 ARTICLE THREE

                   REDEMPTION OF THE COLLATERAL SERIES N BONDS
                        AND THE COLLATERAL SERIES O BONDS

                  SECTION 1. Each Collateral Series N Bond and Collateral Series
Bond shall be redeemable at the option of the Company in whole at any time, or
in part from time to time, prior to maturity, at a redemption price equal to
100% of the principal amount thereof to be redeemed.

                  SECTION 2. The provisions of Sections 3, 4, 5, 6 and 7 of
Article V of the Indenture shall be applicable to the Collateral Series N Bonds
and the Collateral Series O Bonds, except that (a) no publication of notice of
redemption of the Collateral Series N Bonds or the Collateral Series O Bonds
shall be required and (b) if less than all the Collateral Series N Bonds or the
Collateral Series O Bonds are to be redeemed, the Collateral Series N Bonds or
the Collateral Series O Bonds to be redeemed shall be selected in the principal
amounts designated to the Trustee by the Company, and except as such provisions
may otherwise be inconsistent with the provisions of this Article Three.

                  SECTION 3. The holder of each and every Collateral Series N
Bond and Collateral Series O Bond hereby agrees to accept payment thereof prior
to maturity on the terms and conditions provided for in this Article Three.

                                       5



                                  ARTICLE FOUR

                         ACKNOWLEDGMENT OF RIGHT TO VOTE
                           OR CONSENT WITH RESPECT TO
                         CERTAIN AMENDMENTS TO INDENTURE

                  The Company hereby acknowledges the right of the holders of
the Collateral Series N Bonds and the Collateral Series O Bonds to vote or
consent with respect to any or all of the modifications to the Indenture
referred to in Article Three of the Supplemental Indenture, dated as of March 1,
1980, irrespective of the fact that the Bonds of the Second 1987 Series are no
longer outstanding; provided, however, that such acknowledgment shall not impair
(a) the right of the Company to make such modifications without the consent or
other action of the holders of the Bonds of the 2020 Series or the bonds of any
other series subsequently created under the Indenture with respect to which the
Company has expressly reserved such right or (b) the right of the Company to
reserve the right to make such modifications without the consent or other action
of the holders of bonds of one or more, or any or all, series created subsequent
to the creation of the Collateral Series N Bonds and the Collateral Series O
Bonds.

                                  ARTICLE FIVE

                                   THE TRUSTEE

                  The Trustee accepts the trusts created by this Supplemental
Indenture upon the terms and conditions set forth in the Indenture and this
Supplemental Indenture. The recitals in this Supplemental Indenture are made by
the Company only and not by the Trustee. Each and every term and condition
contained in Article XII of the Indenture shall apply to this Supplemental
Indenture with the same force and effect as if the same were herein set forth in
full, with such omissions, variations and modifications thereof as may be
appropriate to make the same conform to this Supplemental Indenture.

                                  ARTICLE SIX

                            MISCELLANEOUS PROVISIONS

                  SECTION 1. Subject to the variations contained in Article
Three of this Supplemental Indenture, the Indenture is in all respects ratified
and confirmed and the Principal Indenture, this Supplemental Indenture and all
other indentures supplemental to the Principal Indenture shall be read, taken
and construed as one and the same instrument. Neither the execution of this
Supplemental Indenture nor anything herein contained shall be construed to
impair the lien of the Indenture on any of the properties subject thereto, and
such lien shall remain in full force and effect as security for all bonds now
outstanding or hereafter issued under the Indenture.

                  All covenants and provisions of the Indenture shall continue
in full force and effect and this Supplemental Indenture shall form part of the
Indenture.

                                       6



                  SECTION 2. If the date for making any payment or the last date
for performance of any act or the exercising of any right, as provided in this
Supplemental Indenture, shall not be a Business Day (as defined in the 1993
Mortgage), such payment may be made or act performed or right exercised on the
next succeeding Business Day with the same force and effect as if done on the
nominal date provided in this Supplemental Indenture.

                  SECTION 3. The terms defined in the Indenture shall, for all
purposes of this Supplemental Indenture, have the meaning specified in the
Indenture except as set forth in Section 4 of this Article or otherwise set
forth in this Supplemental Indenture or unless the context clearly indicates
some other meaning to be intended.

                  SECTION 4. Any term defined in Section 303 of the Trust
Indenture Act of 1939, as amended, and not otherwise defined in the Indenture
shall, with respect to this Supplemental Indenture, the Collateral Series N
Bonds and the Collateral Series O Bonds, have the meaning assigned to such term
in Section 303 as in force on the date of the execution of this Supplemental
Indenture.

                  SECTION 5. This Supplemental Indenture may be executed in any
number of counterparts, and all of said counterparts executed and delivered,
each as an original, shall constitute but one and the same instrument.

                                       7



                  IN WITNESS WHEREOF, Public Service Company of Colorado, party
hereto of the first part, has caused its corporate name to be hereunto affixed,
and this instrument to be signed by its President, an Executive Vice President,
a Senior Vice President or a Vice President, and its corporate seal to be
hereunto affixed and attested by its Secretary or an Assistant Secretary for and
in its behalf; and U.S. Bank Trust National Association, the party hereto of the
second part, in evidence of its acceptance of the trust hereby created, has
caused its corporate name to be hereunto affixed, and this instrument to be
signed and its corporate seal to be affixed by one of its Assistant Vice
Presidents and attested by one of its Trust Officers, for and in its behalf, all
as of the day and year first above written.

                                    PUBLIC SERVICE COMPANY OF
                                      COLORADO

                                    By: /s/ Benjamin G. S. Fowke III
                                        ----------------------------------------
                                        Name:  Benjamin G. S. Fowke III
                                        Title: Vice President and Treasurer

ATTEST: /s/ Anne M. Ziebell
        -------------------------------------
        Name:  Anne M. Ziebell
        Title: Assistant Secretary

STATE OF MINNESOTA        )
                          )  ss.:
CITY OF MINNEAPOLIS       )

                  On this 1st day of September, 2003, before me, Sharon M.
Quellhorst, a duly authorized Notary Public in and for said City in the State
aforesaid, personally appeared Benjamin G. S. Fowke III and Anne M. Ziebell to
me known to be a Vice President and Treasurer and the Assistant Secretary,
respectively, of PUBLIC SERVICE COMPANY OF COLORADO, a corporation organized and
existing under the laws of the State of Colorado, one of the corporations that
executed the within and foregoing instrument; and the said Vice President and
Treasurer and Assistant Secretary severally acknowledged the said instrument to
be the free and voluntary act and deed of said corporation, for the uses and
purposes therein mentioned, and on oath stated that they were authorized to
execute said instrument and that the seal affixed thereto is the corporate seal
of said corporation.

                  IN WITNESS WHEREOF, I have hereunto set my hand and affixed my
official seal the day and year first above written.

                                         /s/ Sharon M. Quellhorst
                                     ---------------------------------------
                                     Name:  Sharon M. Quellhorst
                                     Notary Public, State of Minnesota
                                     Commission Expires:  January 31, 2005

                                       8



                                 U.S. BANK TRUST
                                  NATIONAL ASSOCIATION,
                                     as Trustee

                                 By: /s/ Ignazio Tamburello
                                     -----------------------------------------
                                     Name:  Ignazio Tamburello
                                     Title: Assistant Vice President

ATTEST: /s/ Adam Berman
        -------------------------------
        Name:  Adam Berman
        Title: Trust Officer

STATE OF NEW YORK                )
                                 ) ss.:
CITY AND COUNTY OF NEW YORK      )

                  On this 2nd day of September, 2003, before me, Rouba Fakih, a
duly authorized Notary Public in and for said City and County in the State
aforesaid, personally appeared Ignazio Tamburello and Adam Berman to me known to
be an Assistant Vice President and a Trust Officer, respectively, of U.S. BANK
TRUST NATIONAL ASSOCIATION, a national banking association, one of the
corporations that executed the within and foregoing instrument; and the said
Assistant Vice President and Trust Officer severally acknowledged the said
instrument to be the free and voluntary act and deed of said corporation, for
the uses and purposes therein mentioned, and on oath stated that they were
authorized to execute said instrument and that the seal affixed thereto is the
corporate seal of said corporation.

                  IN WITNESS WHEREOF, I have hereunto set my hand and affixed my
official seal the day and year first above written.

                                 /s/ Rouba Fakih
                                 ----------------------------------------------
                                 Name: Rouba Fakih
                                 Notary Public, State of New York

                                 Commission Expires: February 20, 2007

                                       9



                                                                       EXHIBIT A

                        FORM OF COLLATERAL SERIES N BOND

         THIS BOND IS NOT TRANSFERABLE EXCEPT TO A SUCCESSOR TRUSTEE UNDER THE
INDENTURE, DATED AS OF OCTOBER 1, 1993, AS SUPPLEMENTED, BETWEEN PUBLIC SERVICE
COMPANY OF COLORADO AND U.S. BANK TRUST NATIONAL ASSOCIATION (FORMERLY FIRST
TRUST OF NEW YORK, NATIONAL ASSOCIATION), AS SUCCESSOR TRUSTEE THEREUNDER.

                       PUBLIC SERVICE COMPANY OF COLORADO

                              FIRST MORTGAGE BOND,

                               Collateral Series N

                                    DUE 2008

REGISTERED                                                          REGISTERED

No. _________________                                        $__________________

         FOR VALUE RECEIVED, PUBLIC SERVICE COMPANY OF COLORADO, a corporation
organized and existing under the laws of the State of Colorado (hereinafter
sometimes called the "Company"), promises to pay to U.S. Bank Trust National
Association (formerly known as First Trust of New York, National Association),
as successor trustee (the "1993 Mortgage Trustee") under the Indenture, dated as
of October 1, 1993 (the "1993 Mortgage"), of the Company, or registered assigns,

                                                                         Dollars
on October 1, 2008, at the office or agency of the Company in the city in which
the principal corporate trust office of the 1993 Mortgage Trustee is located.
This bond shall not bear interest. The principal of this bond shall be payable
in any coin or currency of the United States of America which at the time of
payment shall be legal tender for the payment of public and private debts.

         Any payment by the Company under the 1993 Mortgage of the principal of
securities which shall have been authenticated and delivered under the 1993
Mortgage on the basis of the issuance and delivery to the 1993 Mortgage Trustee
of this bond (other than by the application of the proceeds of a payment in
respect of this bond) shall, to the extent thereof, be deemed to satisfy and
discharge the obligation of the Company, if any, to make a payment of principal
of this bond which is then due.

         This bond is one of an issue of bonds of the Company, issued and to be
issued in one or more series under and equally and ratably secured (except as
any sinking, amortization, improvement or other fund, established in accordance
with the provisions of the indenture

                                   Exhibit A-1



hereinafter mentioned, may afford additional security for the bonds of any
particular series) by a certain indenture, dated as of December 1, 1939, made by
the Company to U.S. BANK TRUST NATIONAL ASSOCIATION (formerly First Trust of New
York, National Association), as successor trustee (hereinafter called the
"Trustee") to Morgan Guaranty Trust Company of New York (formerly Guaranty Trust
Company of New York), as amended and supplemented by several indentures
supplemental thereto, including the Supplemental Indenture dated as of September
1, 2003 (said Indenture as amended and supplemented by said indentures
supplemental thereto being hereinafter called the "Indenture"), to which
Indenture reference is hereby made for a description of the property mortgaged,
the nature and extent of the security, the rights and limitations of rights of
the Company, the Trustee, and the holders of said bonds, under the Indenture,
and the terms and conditions upon which said bonds are secured, to all of the
provisions of which Indenture and of all indentures supplemental thereto in
respect of such security, including the provisions of the Indenture permitting
the issue of bonds of any series for property which, under the restrictions and
limitations therein specified, may be subject to liens prior to the lien of the
Indenture, the holder, by accepting this bond, assents. To the extent permitted
by and as provided in the Indenture, the rights and obligations of the Company
and of the holders of said bonds (including those pertaining to any sinking or
other fund) may be changed and modified, with the consent of the Company, by the
holders of at least 75% in aggregate principal amount of the bonds then
outstanding (excluding bonds disqualified from voting by reason of the Company's
interest therein as provided in the Indenture); provided, however, that without
the consent of the holder hereof no such modification or alteration shall be
made which will extend the time of payment of the principal of this bond or
reduce the principal amount hereof or effect any other modification of the terms
of payment of such principal or will reduce the percentage of bonds required for
the aforesaid actions under the Indenture. The Company has reserved the right to
amend the Indenture without any consent or other action by holders of any series
of bonds created after October 31, 1975 (including this series) so as to change
75% in the foregoing sentence to 60% and to change certain procedures relating
to bondholders' meetings. This bond is one of a series of bonds designated as
the First Mortgage Bonds, Collateral Series N, of the Company.

         This bond shall be redeemable at the option of the Company in whole at
any time, or in part from time to time, prior to maturity, at a redemption price
equal to 100% of the principal amount thereof to be redeemed.

         The principal of this bond may be declared or may become due before the
maturity hereof, on the conditions, in the manner and at the times set forth in
the Indenture, upon the happening of an event of default as therein provided.

         This bond is not transferable except to a successor trustee under the
1993 Mortgage, any such transfer to be made at the office or agency of the
Company in the city in which the principal corporate trust office of the 1993
Mortgage Trustee is located, upon surrender and cancellation of this bond, and
thereupon a new bond of this series of a like principal amount will be issued to
the transferee in exchange therefor, as provided in the Indenture. The Company,
the Trustee, any paying agent and any registrar may deem and treat the person in
whose name this bond is registered as the absolute owner hereof for the purpose
of receiving payment and for all other purposes. This bond, alone or with other
bonds of this series, may in like manner be exchanged at such office or agency
for one or more new bonds of this series of the same aggregate principal

                                   Exhibit A-2



amount, all as provided in the Indenture. No service charge shall be made to any
holder of any bond of this series for any exchange or transfer of bonds.

         No recourse under or upon any covenant or obligation of the Indenture,
or of any bonds thereby secured, or for any claim based thereon, or otherwise in
any manner in respect thereof, shall be had against any incorporator, subscriber
to the capital stock, shareholder, officer or director, as such, of the Company,
whether former, present or future, either directly, or indirectly through the
Company or the Trustee, by the enforcement of any subscription to capital stock,
assessment or otherwise, or by any legal or equitable proceeding by virtue of
any statute or otherwise (including, without limiting the generality of the
foregoing, any proceeding to enforce any claimed liability of shareholders of
the Company based upon any theory of disregarding the corporate entity of the
Company or upon any theory that the Company was acting as the agent or
instrumentality of the shareholders), any and all such liability of
incorporators, shareholders, subscribers, officers and directors, as such, being
released by the holder hereof, by the acceptance of this bond, and being
likewise waived and released by the terms of the Indenture under which this bond
is issued.

         This bond shall not be valid or become obligatory for any purpose until
the certificate of authentication endorsed hereon shall have been signed by U.S.
Bank Trust National Association, or its successor, as Trustee under the
Indenture.

         IN WITNESS WHEREOF, Public Service Company of Colorado has caused this
bond to be signed in its name by a Vice President and its corporate seal to be
affixed hereto and attested by its Secretary or an Assistant Secretary.

Dated:                           PUBLIC SERVICE COMPANY OF
                                 COLORADO

                                 By: ______________________________
                                      [Vice President]

ATTEST:________________________
       [Assistant Secretary]

                          CERTIFICATE OF AUTHENTICATION

         This is one of the securities of the series designated therein referred
to in the within-mentioned Supplemental Indenture.

Dated:                           U.S. BANK TRUST
                                 NATIONAL ASSOCIATION,
                                    AS TRUSTEE

                                 By: ______________________________
                                                 Authorized Officer

                                   Exhibit A-3



                                                                       EXHIBIT B

                        FORM OF COLLATERAL SERIES O BOND

         THIS BOND IS NOT TRANSFERABLE EXCEPT TO A SUCCESSOR TRUSTEE UNDER THE
INDENTURE, DATED AS OF OCTOBER 1, 1993, AS SUPPLEMENTED, BETWEEN PUBLIC SERVICE
COMPANY OF COLORADO AND U.S. BANK TRUST NATIONAL ASSOCIATION (FORMERLY FIRST
TRUST OF NEW YORK, NATIONAL ASSOCIATION), AS SUCCESSOR TRUSTEE THEREUNDER.

                       PUBLIC SERVICE COMPANY OF COLORADO

                              FIRST MORTGAGE BOND,

                               Collateral Series O

                                    DUE 2014

REGISTERED                                                       REGISTERED

No._______________                                               $______________

         FOR VALUE RECEIVED, PUBLIC SERVICE COMPANY OF COLORADO, a corporation
organized and existing under the laws of the State of Colorado (hereinafter
sometimes called the "Company"), promises to pay to U.S. Bank Trust National
Association (formerly known as First Trust of New York, National Association),
as successor trustee (the "1993 Mortgage Trustee") under the Indenture, dated as
of October 1, 1993 (the "1993 Mortgage"), of the Company, or registered assigns,

                                                                         Dollars
on April 1, 2014, at the office or agency of the Company in the city in which
the principal corporate trust office of the 1993 Mortgage Trustee is located.
This bond shall not bear interest. The principal of this bond shall be payable
in any coin or currency of the United States of America which at the time of
payment shall be legal tender for the payment of public and private debts.

         Any payment by the Company under the 1993 Mortgage of the principal of
securities which shall have been authenticated and delivered under the 1993
Mortgage on the basis of the issuance and delivery to the 1993 Mortgage Trustee
of this bond (other than by the application of the proceeds of a payment in
respect of this bond) shall, to the extent thereof, be deemed to satisfy and
discharge the obligation of the Company, if any, to make a payment of principal
of this bond which is then due.

         This bond is one of an issue of bonds of the Company, issued and to be
issued in one or more series under and equally and ratably secured (except as
any sinking, amortization, improvement or other fund, established in accordance
with the provisions of the indenture

                                   Exhibit B-1



hereinafter mentioned, may afford additional security for the bonds of any
particular series) by a certain indenture, dated as of December 1, 1939, made by
the Company to U.S. BANK TRUST NATIONAL ASSOCIATION (formerly First Trust of New
York, National Association), as successor trustee (hereinafter called the
"Trustee") to Morgan Guaranty Trust Company of New York (formerly Guaranty Trust
Company of New York), as amended and supplemented by several indentures
supplemental thereto, including the Supplemental Indenture dated as of September
1, 2003 (said Indenture as amended and supplemented by said indentures
supplemental thereto being hereinafter called the "Indenture"), to which
Indenture reference is hereby made for a description of the property mortgaged,
the nature and extent of the security, the rights and limitations of rights of
the Company, the Trustee, and the holders of said bonds, under the Indenture,
and the terms and conditions upon which said bonds are secured, to all of the
provisions of which Indenture and of all indentures supplemental thereto in
respect of such security, including the provisions of the Indenture permitting
the issue of bonds of any series for property which, under the restrictions and
limitations therein specified, may be subject to liens prior to the lien of the
Indenture, the holder, by accepting this bond, assents. To the extent permitted
by and as provided in the Indenture, the rights and obligations of the Company
and of the holders of said bonds (including those pertaining to any sinking or
other fund) may be changed and modified, with the consent of the Company, by the
holders of at least 75% in aggregate principal amount of the bonds then
outstanding (excluding bonds disqualified from voting by reason of the Company's
interest therein as provided in the Indenture); provided, however, that without
the consent of the holder hereof no such modification or alteration shall be
made which will extend the time of payment of the principal of this bond or
reduce the principal amount hereof or effect any other modification of the terms
of payment of such principal or will reduce the percentage of bonds required for
the aforesaid actions under the Indenture. The Company has reserved the right to
amend the Indenture without any consent or other action by holders of any series
of bonds created after October 31, 1975 (including this series) so as to change
75% in the foregoing sentence to 60% and to change certain procedures relating
to bondholders' meetings. This bond is one of a series of bonds designated as
the First Mortgage Bonds, Collateral Series O, of the Company.

         This bond shall be redeemable at the option of the Company in whole at
any time, or in part from time to time, prior to maturity, at a redemption price
equal to 100% of the principal amount thereof to be redeemed.

         The principal of this bond may be declared or may become due before the
maturity hereof, on the conditions, in the manner and at the times set forth in
the Indenture, upon the happening of an event of default as therein provided.

         This bond is not transferable except to a successor trustee under the
1993 Mortgage, any such transfer to be made at the office or agency of the
Company in the city in which the principal corporate trust office of the 1993
Mortgage Trustee is located, upon surrender and cancellation of this bond, and
thereupon a new bond of this series of a like principal amount will be issued to
the transferee in exchange therefor, as provided in the Indenture. The Company,
the Trustee, any paying agent and any registrar may deem and treat the person in
whose name this bond is registered as the absolute owner hereof for the purpose
of receiving payment and for all other purposes. This bond, alone or with other
bonds of this series, may in like manner be exchanged at such office or agency
for one or more new bonds of this series of the same aggregate principal

                                   Exhibit B-2



amount, all as provided in the Indenture. No service charge shall be made to any
holder of any bond of this series for any exchange or transfer of bonds.

         No recourse under or upon any covenant or obligation of the Indenture,
or of any bonds thereby secured, or for any claim based thereon, or otherwise in
any manner in respect thereof, shall be had against any incorporator, subscriber
to the capital stock, shareholder, officer or director, as such, of the Company,
whether former, present or future, either directly, or indirectly through the
Company or the Trustee, by the enforcement of any subscription to capital stock,
assessment or otherwise, or by any legal or equitable proceeding by virtue of
any statute or otherwise (including, without limiting the generality of the
foregoing, any proceeding to enforce any claimed liability of shareholders of
the Company based upon any theory of disregarding the corporate entity of the
Company or upon any theory that the Company was acting as the agent or
instrumentality of the shareholders), any and all such liability of
incorporators, shareholders, subscribers, officers and directors, as such, being
released by the holder hereof, by the acceptance of this bond, and being
likewise waived and released by the terms of the Indenture under which this bond
is issued.

         This bond shall not be valid or become obligatory for any purpose until
the certificate of authentication endorsed hereon shall have been signed by U.S.
Bank Trust National Association, or its successor, as Trustee under the
Indenture.

         IN WITNESS WHEREOF, Public Service Company of Colorado has caused this
bond to be signed in its name by a Vice President and its corporate seal to be
affixed hereto and attested by its Secretary or an Assistant Secretary.

Dated:                           PUBLIC SERVICE COMPANY OF
                                 COLORADO

                                 By: __________________________
                                     [Vice President]

ATTEST:________________________
      [Assistant Secretary]

                          CERTIFICATE OF AUTHENTICATION

         This is one of the securities of the series designated therein referred
to in the within-mentioned Supplemental Indenture.

Dated:                           U.S. BANK TRUST
                                 NATIONAL ASSOCIATION,
                                      AS TRUSTEE

                                 By: _________________________________
                                                    Authorized Officer

                                   Exhibit B-3



                                                                      SCHEDULE A

                             SUPPLEMENTAL INDENTURES



    DATE OF                                                                                       PRINCIPAL
 SUPPLEMENTAL                                                         PRINCIPAL                     AMOUNT
   INDENTURE                        SERIES OF BONDS                 AMOUNT ISSUED                OUTSTANDING
   ---------                        ---------------                 -------------                -----------
                                                                                        
March 14, 1941                              None                                --                    --
May 14, 1941                                None                                --                    --
April 28, 1942                              None                                --                    --
April 14, 1943                              None                                --                    --
April 27, 1944                              None                                --                    --
April 18, 1945                              None                                --                    --
April 23, 1946                              None                                --                    --
April 9, 1947                               None                                --                    --
June 1, 1947*                      2-7/8% Series due 1977          $    40,000,000                  None
April 1, 1948                               None                                --                    --
May 20, 1948                                None                                --                    --
October 1, 1948                    3-1/8% Series due 1978               10,000,000                  None
April 20, 1949                              None                                --                    --
April 24, 1950                              None                                --                    --
April 18, 1951                              None                                --                    --
October 1, 1951                    3-1/4% Series due 1981               15,000,000                  None
April 21, 1952                              None                                --                    --
December 1, 1952                            None                                --                    --
April 15, 1953                              None                                --                    --
April 19, 1954                              None                                --                    --
October 1, 1954*                   3-1/8% Series due 1984               20,000,000                  None
April 18, 1955                              None                                --                    --
April 24, 1956                              None                                --                    --
May 1, 1957*                       4-3/8% Series due 1987               30,000,000                  None
April 10, 1958                              None                                --                    --
May 1, 1959                        4-5/8% Series due 1989               20,000,000                  None
April 18, 1960                              None                                --                    --
April 19, 1961                              None                                --                    --
October 1, 1961                    4-1/2% Series due 1991               30,000,000                  None
March 1, 1962                      4-5/8% Series due 1992                8,800,000                  None
June 1, 1964                       4-1/2% Series due 1994               35,000,000                  None
May 1, 1966                        5-3/8% Series due 1996               35,000,000                  None
July 1, 1967*                      5-7/8% Series due 1997               35,000,000                  None
July 1, 1968*                      6-3/4% Series due 1998               25,000,000                  None
April 25, 1969                              None                                --                    --


                                  Schedule A-1




  DATE OF                                                                                         PRINCIPAL
SUPPLEMENTAL                                                          PRINCIPAL                    AMOUNT
 INDENTURE                           SERIES OF BONDS                AMOUNT ISSUED                OUTSTANDING
- ------------                         ---------------                -------------                -----------
                                                                                        
April 21, 1970                              None                                --                     --
September 1, 1970                  8-3/4% Series due 2000               35,000,000                   None
February 1, 1971                   7-1/4% Series due 2001               40,000,000                   None
August 1, 1972                     7-1/2% Series due 2002               50,000,000                   None
June 1, 1973                       7-5/8% Series due 2003               50,000,000                   None
March 1, 1974                    Pollution Control Series A             24,000,000                   None
December 1, 1974                 Pollution Control Series B             50,000,000                   None
October 1, 1975                    9-3/8% Series due 2005               50,000,000                   None
April 28, 1976                              None                                --                     --

April 28, 1977                              None                                --                     --
November 1, 1977*                  8-1/4% Series due 2007               50,000,000                   None
April 28, 1978                              None                                --                     --
October 1, 1978                    9-1/4% Series due 2008               50,000,000                   None
October 1, 1979*                 Pollution Control Series C             50,000,000                   None
March 1, 1980*                      15% Series due 1987                 50,000,000                   None
April 28, 1981                              None                                --                     --
November 1, 1981*                Pollution Control Series D             27,380,000                   None
December 1, 1981*                 16-1/4% Series due 2011               50,000,000                   None
April 29, 1982                              None                                --                     --
May 1, 1983*                     Pollution Control Series E             42,000,000                   None

April 30, 1984                              None                                --                     --
March 1, 1985*                      13% Series due 2015                 50,000,000                   None
November 1, 1986*                Pollution Control Series F             27,250,000                   None
May 1, 1987*                       8.95% Series due 1992                75,000,000                   None
July 1, 1990*                      9-7/8% Series due 2020               75,000,000                   None
December 1, 1990*           Secured Medium-Term Notes, Series A        191,500,000**                 None
March 1, 1992*                   8-1/8% Series due 2004 and            100,000,000               100,000,000
                                   8-3/4% Series due 2022              150,000,000                   None
April 1, 1993*                   Pollution Control Series G             79,500,000                79,500,000
June 1, 1993*                    Pollution Control Series H             50,000,000                50,000,000
November 1, 1993*                   Collateral Series A                134,500,000               134,500,000

January 1, 1994*              Collateral Series B due 2001 and         102,667,000                   None
                                Collateral Series B due 2024           110,000,000               110,000,000
September 2, 1994                           None                                --                     --
(Appointment of
Successor Trustee)
May 1, 1996                         Collateral Series C                125,000,000               125,000,000


                                  Schedule A-2





  DATE OF                                                                                         PRINCIPAL
SUPPLEMENTAL                                                          PRINCIPAL                    AMOUNT
 INDENTURE                           SERIES OF BONDS                AMOUNT ISSUED                OUTSTANDING
 ---------                           ---------------                -------------                -----------
                                                                                        
November 1, 1996                    Collateral Series D              250,000,000                 175,000,000
February 1, 1997                    Collateral Series E              150,000,000                    None
April 1, 1998                       Collateral Series F              250,000,000                    None
August 15, 2002                     Collateral Series G               48,750,000                  48,750,000
September 1, 2002                   Collateral Series H              600,000,000                    None
September 15, 2002                  Collateral Series I              530,000,000                    None
April 1, 2003                       Collateral Series J              600,000,000                 600,000,000
March 1, 2003                       Collateral Series K              250,000,000                 250,000,000
May 1, 2003                         Collateral Series M              350,000,000                 350,000,000


- --------------------------

* Contains amendatory provisions

** $200,000,000 authorized

                                  Schedule A-3

EX-4.02

                             PUBLIC SERVICE COMPANY
                                   OF COLORADO

                                       TO

                      U.S. BANK TRUST NATIONAL ASSOCIATION,

                                             AS TRUSTEE

                             -----------------------

                          SUPPLEMENTAL INDENTURE NO. 15

                          Dated as of September 1, 2003

                          Supplemental to the Indenture
                           dated as of October 1, 1993

                            -----------------------

         Establishing the Securities of Series No. 14 and Series No. 15,
           designated First Collateral Trust Bonds, Series No. 14 and
            First Collateral Trust Bonds, Series No. 15, respectively



         SUPPLEMENTAL INDENTURE NO. 15, dated as of September 1, 2003, between
PUBLIC SERVICE COMPANY OF COLORADO, a corporation duly organized and existing
under the laws of the State of Colorado (hereinafter sometimes called the
"Company"), and U.S. BANK TRUST NATIONAL ASSOCIATION (FORMERLY FIRST TRUST OF
NEW YORK, NATIONAL ASSOCIATION), a national banking association, as successor
trustee (hereinafter sometimes called the "Trustee") to Morgan Guaranty Trust
Company of New York under the Indenture, dated as of October 1, 1993
(hereinafter called the "Original Indenture"), as previously supplemented and as
further supplemented by this Supplemental Indenture No. 15. The Original
Indenture and any and all indentures and all other instruments supplemental
thereto are hereinafter sometimes collectively called the "Indenture".

                             RECITALS OF THE COMPANY

         The Original Indenture was authorized, executed and delivered by the
Company to provide for the issuance from time to time of its Securities (such
term and all other capitalized terms used herein without definition having the
meanings assigned to them in the Original Indenture), to be issued in one or
more series as contemplated therein, and to provide security for the payment of
the principal of and premium, if any, and interest, if any, on the Securities.

         The Company has heretofore executed and delivered to the Trustee the
Supplemental Indentures referred to in Schedule A hereto for the purpose of
establishing a series of bonds and appointing the successor Trustee.

         The Company desires to establish two new series of Securities to be
designated "First Collateral Trust Bonds, Series No. 14" and "First Collateral
Trust Bonds, Series No. 15", such series of Securities to be hereinafter
sometimes called "Series No. 14" and "Series No. 15," respectively.

         The Company has duly authorized the execution and delivery of this
Supplemental Indenture No. 15 to establish the Securities of Series No. 14 and
Series No. 15 and has duly authorized the issuance of such Securities; and all
acts necessary to make this Supplemental Indenture No. 15 a valid agreement of
the Company, and to make the Securities of Series No. 14 and Series No. 15 valid
obligations of the Company, have been performed.

                                GRANTING CLAUSES

         NOW, THEREFORE, THIS SUPPLEMENTAL INDENTURE NO. 15 WITNESSETH, that, in
consideration of the premises and of the purchase of the Securities by the
Holders thereof, and in order to secure the payment of the principal of and
premium, if any, and interest, if any, on all Securities from time to time
Outstanding and the performance of the covenants contained therein and in the
Indenture and to declare the terms and conditions on which such Securities are
secured, the Company hereby grants, bargains, sells, releases, conveys, assigns,
transfers, mortgages, pledges, sets over and confirms to the Trustee, and grants
to the Trustee a security interest in, the following:

                              GRANTING CLAUSE FIRST

                  All right, title and interest of the Company, as of the date
         of the execution and delivery of this Supplemental Indenture No. 15, in
         and to property (other than Excepted Property), real, personal and
         mixed and wherever situated, in any case used or to be used in or in
         connection with the Electric Utility Business (whether or not such use
         is the sole use of such property), including without limitation (a) all
         lands, easements, servitudes, licenses, permits, rights of way and
         other rights and interests in or relating to real property used or to
         be used in or in connection with the Electric Utility Business or
         relating to the occupancy or use of such real property, subject
         however, to the exceptions



         and exclusions set forth in clause (a) of Granting Clause First of the
         Original Indenture; (b) all plants, generators, turbines, engines,
         boilers, fuel handling and transportation facilities, air and water
         pollution control and sewage and solid waste disposal facilities and
         other machinery and facilities for the generation of electric energy;
         (c) all switchyards, lines, towers, substations, transformers and other
         machinery and facilities for the transmission of electric energy; (d)
         all lines, poles, conduits, conductors, meters, regulators and other
         machinery and facilities for the distribution of electric energy; (e)
         all buildings, offices, warehouses and other structures used or to be
         used in or in connection with the Electric Utility Business; (f) all
         pipes, cables, insulators, ducts, tools, computers and other data
         processing and/or storage equipment and other equipment, apparatus and
         facilities used or to be used in or in connection with the Electric
         Utility Business; (g) any or all of the foregoing properties in the
         process of construction; and (h) all other property, of whatever kind
         and nature, ancillary to or otherwise used or to be used in conjunction
         with any or all of the foregoing or otherwise, directly or indirectly,
         in furtherance of the Electric Utility Business;

                             GRANTING CLAUSE SECOND

                  Subject to the applicable exceptions permitted by Section
         810(c), Section 1303 and Section 1305 of the Original Indenture, all
         property (other than Excepted Property) of the kind and nature
         described in Granting Clause First which may be hereafter acquired by
         the Company, it being the intention of the Company that all such
         property acquired by the Company after the date of the execution and
         delivery of this Supplemental Indenture No. 15 shall be as fully
         embraced within and subjected to the Lien hereof as if such property
         were owned by the Company as of the date of the execution and delivery
         of this Supplemental Indenture No. 15;

                             GRANTING CLAUSE FOURTH

                  All other property of whatever kind and nature subjected or
         required to be subjected to the Lien of the Indenture by any of the
         provisions thereof;

                                EXCEPTED PROPERTY

                  Expressly excepting and excluding, however, from the Lien and
         operation of the Indenture all Excepted Property of the Company,
         whether now owned or hereafter acquired;

         TO HAVE AND TO HOLD all such property, real, personal and mixed, unto
the Trustee, its successors in trust and their assigns forever;

         SUBJECT, HOWEVER, to (a) Liens existing at the date of the execution
and delivery of the Original Indenture (including, but not limited to, the Lien
of the PSCO 1939 Mortgage), (b) as to property acquired by the Company after the
date of the execution and delivery of the Original Indenture, Liens existing or
placed thereon at the time of the acquisition thereof (including, but not
limited to, the Lien of any Class A Mortgage and purchase money Liens), (c)
Retained Interests and (d) any other Permitted Liens, it being understood that,
with respect to any property which was at the date of execution and delivery of
the Original Indenture or thereafter became or hereafter becomes subject to the
Lien of any Class A Mortgage, the Lien of the Indenture shall at all times be
junior, subject and subordinate to the Lien of such Class A Mortgage;

                                       2



         IN TRUST, NEVERTHELESS, for the equal and proportionate benefit and
security of the Holders from time to time of all Outstanding Securities without
any priority of any such Security over any other such Security;

         PROVIDED, HOWEVER, that the right, title and interest of the Trustee in
and to the Mortgaged Property shall cease, terminate and become void in
accordance with, and subject to the conditions set forth in, Article Nine of the
Original Indenture, and if, thereafter, the principal of and premium, if any,
and interest, if any, on the Securities shall have been paid to the Holders
thereof, or shall have been paid to the Company pursuant to Section 603 of the
Original Indenture, then and in that case the Indenture shall terminate, and the
Trustee shall execute and deliver to the Company such instruments as the Company
shall require to evidence such termination; otherwise the Indenture, and the
estate and rights thereby granted shall be and remain in full force and effect;
and

         THE PARTIES HEREBY FURTHER COVENANT AND AGREE as follows:

                                  ARTICLE ONE

                           SECURITIES OF SERIES NO. 14

         There are hereby established the Securities of Series No. 14, which
shall have the terms and characteristics set forth below (the lettered
subdivisions set forth below corresponding to the lettered subdivisions of
Section 301 of the Original Indenture):

         (a)      the title of the Securities of Series No. 14 shall be "First
         Collateral Trust Bonds, Series No. 14"; provided, however, that, at any
         time after the PSCO 1939 Mortgage shall have been satisfied and
         discharged, the Company shall have the right, without any consent or
         other action by the Holders of the Securities, to change the title of
         the series in such manner as shall be deemed by the Company to be
         appropriate to reflect such satisfaction and discharge, such change to
         be evidenced in an Officer's Certificate;

         (b)      the Securities of Series No. 14 shall be initially
         authenticated and delivered in the aggregate principal amount of
         $300,000,000;

         (c)      interest on the Securities of Series No. 14 shall be payable
         to the Persons in whose names such Securities are registered at the
         close of business on the Regular Record Date for such interest, except
         as otherwise expressly provided in the form of such Securities attached
         as Exhibit A hereto;

         (d)      the principal of the Securities of Series No. 14 shall be
         payable on October 1, 2008, the Stated Maturity for Series No. 14;

         (e)      the Securities of Series No. 14 shall bear interest at a rate
         of 4.375% per annum; interest shall accrue on the Securities of Series
         No. 14 from September 9, 2003, or the most recent date to which
         interest has been paid or duly provided for; the Interest Payment Dates
         for such Securities shall be April 1 and October 1 in each year,
         commencing April 1, 2004, and the Regular Record Dates with respect to
         the Interest Payment Dates for such Securities shall be March 15 and
         September 15 in each year, respectively (whether or not a Business
         Day);

                                       3



         (f)      the Corporate Trust Office of U.S. Bank Trust National
         Association in New York, New York shall be the place at which (i) the
         principal of, premium, if any, and interest, if any, on the Securities
         of Series No. 14 shall be payable, (ii) registration of transfer of
         such Securities may be effected, (iii) exchanges of such Securities may
         be effected and (iv) notices and demands to or upon the Company in
         respect of such Securities and the Indenture may be served; and U.S.
         Bank Trust National Association shall be the Security Registrar for
         such Securities; provided, however, that the Company reserves the right
         to change, by one or more Officer's Certificates, any such place or the
         Security Registrar; and provided, further, that the Company reserves
         the right to designate, by one or more Officer's Certificates, its
         principal office in Denver, Colorado as any such place or itself as the
         Security Registrar;

         (g)      the Securities of Series No. 14 shall be redeemable at the
         option of the Company at any time prior to their Maturity, in whole or
         in part, at a redemption price equal to the greater of (i) 100% of the
         principal amount thereof to be redeemed, or (ii) the sum of the present
         values of the remaining scheduled payments of principal and interest on
         such Securities to be redeemed, discounted to the Redemption Date on a
         semi-annual basis (assuming a 360-day year consisting of twelve 30-day
         months) at the Treasury Yield plus 15 basis points, plus in each case,
         accrued and unpaid interest to the Redemption Date. For purposes
         hereof, the following defined terms shall have the meaning ascribed to
         them:

                  "Treasury Yield" means, for any Redemption Date, the rate per
         annum equal to the semi-annual equivalent yield to maturity of the
         Comparable Treasury Issue, assuming a price for the Comparable Treasury
         Issue (expressed as a percentage of its principal amount) equal to the
         Comparable Treasury Price for the Redemption Date.

                  "Comparable Treasury Issue" means the United States Treasury
         security selected by the Independent Investment Banker as having a
         maturity comparable to the remaining term of the Securities of Series
         No. 14 that would be utilized, at the time of selection and in
         accordance with customary financial practice, in pricing new issues of
         corporate debt securities of comparable maturity to the remaining term
         of the Securities of Series No. 14.

                  "Comparable Treasury Price" means, for any Redemption Date,
         (i) the average of the bid and asked prices for the Comparable Treasury
         Issue (expressed in each case as a percentage of its principal amount)
         on the third Business Day preceding the Redemption Date, as set forth
         in the daily statistical release (or any successor release) published
         by the Federal Reserve Bank of New York and designated "Composite 3:30
         p.m. Quotations for U.S. Government Securities" or (ii) if that release
         (or any successor release) is not published or does not contain those
         prices on that Business Day, (A) the average of the Reference Treasury
         Dealer Quotations for the Redemption Date, after excluding the highest
         and lowest Reference Treasury Dealer Quotations for the Redemption
         Date, or (B) if the Trustee obtains fewer than four Reference Treasury
         Dealer Quotations, the average of all of the Quotations.

                  "Independent Investment Banker" means Banc One Capital
         Markets, Inc., or its successor or, if such firm or its successor is
         unwilling or unable to select the Comparable Treasury Issue, one of the
         remaining Reference Treasury Dealers appointed by the Trustee after
         consultation with the Company.

                  "Reference Treasury Dealer" means (i) each of Banc One Capital
         Markets, Inc., McDonald Investments Inc. or UBS Securities LLC and any
         other Primary Treasury Dealer

                                       4



         designated by, and not affiliated with, Banc One Capital Markets, Inc.,
         McDonald Investments Inc. or UBS Securities LLC and their respective
         successors, provided, however, that if any of the foregoing or any of
         its designees ceases to be a Primary Treasury Dealer, the Company will
         appoint another Primary Treasury Dealer as a substitute and (ii) any
         other Primary Treasury Dealer selected by the Company.

                  "Primary Treasury Dealer" means any primary U.S. Government
         securities dealer in the United States.

                  "Reference Treasury Dealer Quotations" means, for each
         Reference Treasury Dealer and any Redemption Date, the average, as
         determined by the Independent Investment Banker, of the bid and asked
         prices for the Comparable Treasury Issue (expressed in each case as a
         percentage of its principal amount) quoted in writing to the
         Independent Investment Banker by the Reference Treasury Dealer at 5:00
         p.m. on the third Business Day preceding the Redemption Date.

         (h)      not applicable;

         (i)      not applicable;

         (j)      not applicable;

         (k)      not applicable;

         (l)      not applicable;

         (m)      not applicable;

         (n)      not applicable;

         (o)      not applicable;

         (p)      not applicable;

         (q)      the Securities of Series No. 14 are to be initially registered
         in the name of Cede & Co., as nominee for The Depository Trust Company
         (the "Depositary"). Such Securities shall not be transferable or
         exchangeable, nor shall any purported transfer be registered, except as
         follows:

                  (i)      such Securities may be transferred in whole, and
                  appropriate registration of transfer effected, if such
                  transfer is by such nominee to the Depositary, or by the
                  Depositary to another nominee thereof, or by any nominee of
                  the Depositary to any other nominee thereof, or by the
                  Depositary or any nominee thereof to any successor securities
                  depositary or any nominee thereof; and

                  (ii)     such Securities may be exchanged for definitive
                  Securities registered in the respective names of the
                  beneficial holders thereof, and thereafter shall be
                  transferable without restriction, if:

                           (A)      the Depositary, or any successor securities
                           depositary, shall have notified the Company and the
                           Trustee that it is unwilling or unable to continue to
                           act as securities depositary with respect to such
                           Securities or the Depositary has ceased to be a
                           clearing agency registered under the

                                       5



                           Securities Exchange Act of 1934, as amended, and the
                           Trustee shall not have been notified by the Company
                           within ninety (90) days of the identity of a
                           successor securities depositary with respect to such
                           Securities; or

                           (B)      the Company shall have delivered to the
                           Trustee a Company Order to the effect that such
                           Securities shall be so exchangeable on and after a
                           date specified therein;

         (r)      not applicable;

         (s)      no service charge shall be made for the registration of
         transfer or exchange of the Securities of Series No. 14; provided,
         however, that the Company may require payment of a sum sufficient to
         cover any tax or other governmental charge payable in connection with
         the exchange or transfer;

         (t)      not applicable;

         (u)      (i)      If the Company shall have caused the Company's
                  indebtedness in respect of any Securities of Series No. 14 to
                  have been satisfied and discharged prior to the Maturity of
                  such Securities, as provided in Section 901 of the Original
                  Indenture, the Company shall, promptly after the date of such
                  satisfaction and discharge, give a notice to each Person who
                  was a Holder of any of such Securities on such date stating
                  (A)(1) the aggregate principal amount of such Securities and
                  (2) the aggregate amount of any money (other than amounts, if
                  any, deposited in respect of accrued interest on such
                  Securities) and the aggregate principal amount of, the rate or
                  rates of interest on, and the aggregate fair market value of,
                  any Eligible Obligations deposited pursuant to Section 901 of
                  the Original Indenture with respect to such Securities and (B)
                  that the Company will provide (and the Company shall promptly
                  so provide) to such Person, or any beneficial owner of such
                  Securities holding through such Person (upon written request
                  to the Company sent to an address specified in such notice),
                  such other information as such Person or beneficial owner, as
                  the case may be, reasonably may request in order to enable it
                  to determine the federal income tax consequences to it
                  resulting from the satisfaction and discharge of the Company's
                  indebtedness in respect of such Securities. Thereafter, the
                  Company shall, within forty-five (45) days after the end of
                  each calendar year, give to each Person who at any time during
                  such calendar year was a Holder of such Securities a notice
                  containing (X) such information as may be necessary to enable
                  such Person to report its income, gain or loss for federal
                  income tax purposes with respect to such Securities or the
                  assets held on deposit in respect thereof during such calendar
                  year or the portion thereof during which such Person was a
                  Holder of such Securities, as the case may be (such
                  information to be set forth for such calendar year as a whole
                  and for each month during such year) and (Y) a statement to
                  the effect that the Company will provide (and the Company
                  shall promptly so provide) to such Person, or any beneficial
                  owner of such Securities holding through such Person (upon
                  written request to the Company sent to an address specified in
                  such notice), such other information as such Person or
                  beneficial owner, as the case may be, reasonably may request
                  in order to enable it to determine its income, gain or loss
                  for federal income tax purposes with respect to such
                  Securities or such assets for such year or portion

                                       6



                  thereof, as the case may be. The obligation of the Company to
                  provide or cause to be provided information for purposes of
                  income tax reporting by any Person as described in the first
                  two sentences of this paragraph shall be deemed to have been
                  satisfied to the extent that the Company has provided or
                  caused to be provided substantially comparable information
                  pursuant to any requirements of the Internal Revenue Code of
                  1986, as amended from time to time (the "Code") and United
                  States Treasury regulations thereunder.

                  (ii)     Notwithstanding the provisions of subparagraph (i)
                  above, the Company shall not be required to give any notice
                  specified in such subparagraph or to otherwise furnish any of
                  the information contemplated therein if the Company shall have
                  delivered to the Trustee an Opinion of Counsel to the effect
                  that the Holders of such Securities will not recognize income,
                  gain or loss for federal income tax purposes as a result of
                  the satisfaction and discharge of the Company's indebtedness
                  in respect of such Securities and such Holders will be subject
                  to federal income taxation on the same amounts and in the same
                  manner and at the same times as if such satisfaction and
                  discharge had not occurred.

                  (iii)    Anything in this clause (u) to the contrary
                  notwithstanding, the Company shall not be required to give any
                  notice specified in subparagraph (i) or to otherwise furnish
                  the information contemplated therein or to deliver any Opinion
                  of Counsel contemplated by subparagraph (ii) if the Company
                  shall have caused Securities of Series No. 14 to be deemed to
                  have been paid for purposes of the Indenture, as provided in
                  Section 901 of the Original Indenture, but shall not have
                  effected the satisfaction and discharge of its indebtedness in
                  respect of such Securities pursuant to such Section.

         (v)      The Securities of Series No. 14 shall be substantially in the
         form attached hereto as Exhibit A and shall have such further terms as
         are set forth in such form.

                                  ARTICLE TWO

                           SECURITIES OF SERIES NO. 15

         There are hereby established the Securities of Series No. 15, which
shall have the terms and characteristics set forth below (the lettered
subdivisions set forth below corresponding to the lettered subdivisions of
Section 301 of the Original Indenture):

         (a)      the title of the Securities of Series No. 15 shall be "First
         Collateral Trust Bonds, Series No. 15"; provided, however, that, at any
         time after the PSCO 1939 Mortgage shall have been satisfied and
         discharged, the Company shall have the right, without any consent or
         other action by the Holders of the Securities, to change the title of
         the series in such manner as shall be deemed by the Company to be
         appropriate to reflect such satisfaction and discharge, such change to
         be evidenced in an Officer's Certificate;

         (b)      the Securities of Series No. 15 shall be initially
         authenticated and delivered in the aggregate principal amount of
         $275,000,000;

         (c)      interest on the Securities of Series No. 15 shall be payable
         to the Persons in whose names such Securities are registered at the
         close of business on the Regular

                                       7



         Record Date for such interest, except as otherwise expressly provided
         in the form of such Securities attached as Exhibit B hereto;

         (d)      the principal of the Securities of Series No. 15 shall be
         payable on April 1, 2014, the Stated Maturity for Series No. 15;

         (e)      the Securities of Series No. 15 shall bear interest at a rate
         of 5.50% per annum; interest shall accrue on the Securities of Series
         No. 15 from September 9, 2003, or the most recent date to which
         interest has been paid or duly provided for; the Interest Payment Dates
         for such Securities shall be April 1 and October 1 in each year,
         commencing April 1, 2004, and the Regular Record Dates with respect to
         the Interest Payment Dates for such Securities shall be March 15 and
         September 15 in each year, respectively (whether or not a Business
         Day);

         (f)      the Corporate Trust Office of U.S. Bank Trust National
         Association in New York, New York shall be the place at which (i) the
         principal of, premium, if any, and interest, if any, on the Securities
         of Series No. 15 shall be payable, (ii) registration of transfer of
         such Securities may be effected, (iii) exchanges of such Securities may
         be effected and (iv) notices and demands to or upon the Company in
         respect of such Securities and the Indenture may be served; and U.S.
         Bank Trust National Association shall be the Security Registrar for
         such Securities; provided, however, that the Company reserves the right
         to change, by one or more Officer's Certificates, any such place or the
         Security Registrar; and provided, further, that the Company reserves
         the right to designate, by one or more Officer's Certificates, its
         principal office in Denver, Colorado as any such place or itself as the
         Security Registrar;

         (g)      the Securities of Series No. 15 shall be redeemable at the
         option of the Company at any time prior to their Maturity, in whole or
         in part, at a redemption price equal to the greater of (i) 100% of the
         principal amount thereof to be redeemed, or (ii) the sum of the present
         values of the remaining scheduled payments of principal and interest on
         such Securities to be redeemed, discounted to the Redemption Date on a
         semi-annual basis (assuming a 360-day year consisting of twelve 30-day
         months) at the Treasury Yield plus 20 basis points, plus in each case,
         accrued and unpaid interest to the Redemption Date. For purposes
         hereof, the following defined terms shall have the meaning ascribed to
         them:

                  "Treasury Yield" means, for any Redemption Date, the rate per
         annum equal to the semi-annual equivalent yield to maturity of the
         Comparable Treasury Issue, assuming a price for the Comparable Treasury
         Issue (expressed as a percentage of its principal amount) equal to the
         Comparable Treasury Price for the Redemption Date.

                  "Comparable Treasury Issue" means the United States Treasury
         security selected by the Independent Investment Banker as having a
         maturity comparable to the remaining term of the Securities of Series
         No. 15 that would be utilized, at the time of selection and in
         accordance with customary financial practice, in pricing new issues of
         corporate debt securities of comparable maturity to the remaining term
         of the Securities of Series No. 15.

                  "Comparable Treasury Price" means, for any Redemption Date,
         (i) the average of the bid and asked prices for the Comparable Treasury
         Issue (expressed in each case as a percentage of its principal amount)
         on the third Business Day preceding the Redemption Date, as set forth
         in the daily statistical release (or any successor release) published
         by the Federal Reserve Bank of New

                                       8



         York and designated "Composite 3:30 p.m. Quotations for U.S. Government
         Securities" or (ii) if that release (or any successor release) is not
         published or does not contain those prices on that Business Day, (A)
         the average of the Reference Treasury Dealer Quotations for the
         Redemption Date, after excluding the highest and lowest Reference
         Treasury Dealer Quotations for the Redemption Date, or (B) if the
         Trustee obtains fewer than four Reference Treasury Dealer Quotations,
         the average of all of the Quotations.

                  "Independent Investment Banker" means Banc One Capital
         Markets, Inc., or its successor or, if such firm or its successor is
         unwilling or unable to select the Comparable Treasury Issue, one of the
         remaining Reference Treasury Dealers appointed by the Trustee after
         consultation with the Company.

                  "Reference Treasury Dealer" means (i) each of Banc One Capital
         Markets, Inc., McDonald Investments Inc. or UBS Securities LLC and any
         other Primary Treasury Dealer designated by, and not affiliated with,
         Banc One Capital Markets, Inc., McDonald Investments Inc. or UBS
         Securities LLC and their respective successors, provided, however, that
         if any of the foregoing or any of its designees ceases to be a Primary
         Treasury Dealer, the Company will appoint another Primary Treasury
         Dealer as a substitute and (ii) any other Primary Treasury Dealer
         selected by the Company.

                  "Primary Treasury Dealer" means any primary U.S. Government
         securities dealer in the United States.

                  "Reference Treasury Dealer Quotations" means, for each
         Reference Treasury Dealer and any Redemption Date, the average, as
         determined by the Independent Investment Banker, of the bid and asked
         prices for the Comparable Treasury Issue (expressed in each case as a
         percentage of its principal amount) quoted in writing to the
         Independent Investment Banker by the Reference Treasury Dealer at 5:00
         p.m. on the third Business Day preceding the Redemption Date.

         (h)      not applicable;

         (i)      not applicable;

         (j)      not applicable;

         (k)      not applicable;

         (l)      not applicable;

         (m)      not applicable;

         (n)      not applicable;

         (o)      not applicable;

         (p)      not applicable;

         (q)      the Securities of Series No. 15 are to be initially registered
         in the name of Cede & Co., as nominee for The Depository Trust Company
         (the "Depositary"). Such Securities shall not be transferable or
         exchangeable, nor shall any purported transfer be registered, except as
         follows:

                                       9



                  (i)      such Securities may be transferred in whole, and
                  appropriate registration of transfer effected, if such
                  transfer is by such nominee to the Depositary, or by the
                  Depositary to another nominee thereof, or by any nominee of
                  the Depositary to any other nominee thereof, or by the
                  Depositary or any nominee thereof to any successor securities
                  depositary or any nominee thereof; and

                  (ii)     such Securities may be exchanged for definitive
                  Securities registered in the respective names of the
                  beneficial holders thereof, and thereafter shall be
                  transferable without restriction, if:

                           (A)      the Depositary, or any successor securities
                           depositary, shall have notified the Company and the
                           Trustee that it is unwilling or unable to continue to
                           act as securities depositary with respect to such
                           Securities or the Depositary has ceased to be a
                           clearing agency registered under the Securities
                           Exchange Act of 1934, as amended, and the Trustee
                           shall not have been notified by the Company within
                           ninety (90) days of the identity of a successor
                           securities depositary with respect to such
                           Securities; or

                           (B)      the Company shall have delivered to the
                           Trustee a Company Order to the effect that such
                           Securities shall be so exchangeable on and after a
                           date specified therein;

         (r)      not applicable;

         (s)      no service charge shall be made for the registration of
         transfer or exchange of the Securities of Series No. 15; provided,
         however, that the Company may require payment of a sum sufficient to
         cover any tax or other governmental charge payable in connection with
         the exchange or transfer;

         (t)      not applicable;

         (u)      (i)      If the Company shall have caused the Company's
                  indebtedness in respect of any Securities of Series No. 15 to
                  have been satisfied and discharged prior to the Maturity of
                  such Securities, as provided in Section 901 of the Original
                  Indenture, the Company shall, promptly after the date of such
                  satisfaction and discharge, give a notice to each Person who
                  was a Holder of any of such Securities on such date stating
                  (A)(1) the aggregate principal amount of such Securities and
                  (2) the aggregate amount of any money (other than amounts, if
                  any, deposited in respect of accrued interest on such
                  Securities) and the aggregate principal amount of, the rate or
                  rates of interest on, and the aggregate fair market value of,
                  any Eligible Obligations deposited pursuant to Section 901 of
                  the Original Indenture with respect to such Securities and (B)
                  that the Company will provide (and the Company shall promptly
                  so provide) to such Person, or any beneficial owner of such
                  Securities holding through such Person (upon written request
                  to the Company sent to an address specified in such notice),
                  such other information as such Person or beneficial owner, as
                  the case may be, reasonably may request in order to enable it
                  to determine the federal income tax consequences to it
                  resulting from the satisfaction and discharge of the Company's
                  indebtedness in respect of such Securities. Thereafter, the
                  Company shall, within forty-five (45) days after the end of
                  each calendar year, give to each

                                       10



         Person who at any time during such calendar year was a Holder of such
         Securities a notice containing (X) such information as may be necessary
         to enable such Person to report its income, gain or loss for federal
         income tax purposes with respect to such Securities or the assets held
         on deposit in respect thereof during such calendar year or the portion
         thereof during which such Person was a Holder of such Securities, as
         the case may be (such information to be set forth for such calendar
         year as a whole and for each month during such year) and (Y) a
         statement to the effect that the Company will provide (and the Company
         shall promptly so provide) to such Person, or any beneficial owner of
         such Securities holding through such Person (upon written request to
         the Company sent to an address specified in such notice), such other
         information as such Person or beneficial owner, as the case may be,
         reasonably may request in order to enable it to determine its income,
         gain or loss for federal income tax purposes with respect to such
         Securities or such assets for such year or portion thereof, as the case
         may be. The obligation of the Company to provide or cause to be
         provided information for purposes of income tax reporting by any Person
         as described in the first two sentences of this paragraph shall be
         deemed to have been satisfied to the extent that the Company has
         provided or caused to be provided substantially comparable information
         pursuant to any requirements of the Internal Revenue Code of 1986, as
         amended from time to time (the "Code") and United States Treasury
         regulations thereunder.

         (i)      Notwithstanding the provisions of subparagraph (i) above, the
         Company shall not be required to give any notice specified in such
         subparagraph or to otherwise furnish any of the information
         contemplated therein if the Company shall have delivered to the Trustee
         an Opinion of Counsel to the effect that the Holders of such Securities
         will not recognize income, gain or loss for federal income tax purposes
         as a result of the satisfaction and discharge of the Company's
         indebtedness in respect of such Securities and such Holders will be
         subject to federal income taxation on the same amounts and in the same
         manner and at the same times as if such satisfaction and discharge had
         not occurred.

         (ii)     Anything in this clause (u) to the contrary notwithstanding,
         the Company shall not be required to give any notice specified in
         subparagraph (i) or to otherwise furnish the information contemplated
         therein or to deliver any Opinion of Counsel contemplated by
         subparagraph (ii) if the Company shall have caused Securities of Series
         No. 15 to be deemed to have been paid for purposes of the Indenture, as
         provided in Section 901 of the Original Indenture, but shall not have
         effected the satisfaction and discharge of its indebtedness in respect
         of such Securities pursuant to such Section.

(v)      The Securities of Series No. 15 shall be substantially in the form
attached hereto as Exhibit B and shall have such further terms as are set forth
in such form.

                                       11



                                 ARTICLE THREE

                            MISCELLANEOUS PROVISIONS

         This Supplemental Indenture No. 15 is a supplement to the Original
Indenture. As previously supplemented and further supplemented by this
Supplemental Indenture No. 15, the Original Indenture is in all respects
ratified, approved and confirmed, and the Original Indenture, all previous
supplements thereto and this Supplemental Indenture No. 15 shall together
constitute one and the same instrument.

                                       12



                  IN WITNESS WHEREOF, the parties hereto have caused this
Supplemental Indenture No. 15 to be duly executed as of the day and year first
above written.

                                      PUBLIC SERVICE COMPANY OF COLORADO

                                      By: /s/ Benjamin G. S. Fowke III
                                          --------------------------------------

                                          Name: Benjamin G. S. Fowke III
                                          Title: Vice President and Treasurer

STATE OF MINNESOTA         )
                           ) ss.:
CITY OF MINNEAPOLIS        )

         On the 1st day of September, 2003, before me personally came Benjamin
G. S. Fowke III to me known, who, being by me duly sworn, did depose and say
that he is a Vice President and Treasurer of Public Service Company of Colorado,
one of the corporations described in and which executed the foregoing
instrument; and that he signed his name thereto by authority of the Board of
Directors of said corporation.

                                      /s/ Sharon M. Quellhorst
                                      ------------------------------------------
                                      Name: Sharon M. Quellhorst
                                      Notary Public, State of Minnesota

                                      Commission Expires:  January 31, 2005

                                       13



                                      U.S. BANK TRUST NATIONAL ASSOCIATION,
                                                             Trustee

                                      By: /s/ Ignazio Tamburello
                                          --------------------------------------

                                          Name: Ignazio Tamburello
                                          Title: Assistant Vice President

STATE OF NEW YORK              )
                               ) ss.:
CITY AND COUNTY OF NEW YORK    )

         On the 2nd day of September, 2003, before me personally came Ignazio
Tamburello, to me known, who, being by me duly sworn, did depose and say that he
is an Assistant Vice President of U.S. Bank Trust National Association, the
banking association described in and which executed the foregoing instrument;
and that he signed his name thereto by authority of the Board of Directors of
said banking association.

                                      /s/ Rouba Fakih
                                      ------------------------------------------
                                      Name: Rouba Fakih
                                      Notary Public, State of New York

                                      Commission Expires: February 20, 2007

                                       14



                                                                       EXHIBIT A

                                FORM OF SECURITY

                   (See legend at the end of this Security for
                            restrictions on transfer)

                       PUBLIC SERVICE COMPANY OF COLORADO
                   First Collateral Trust Bond, Series No. 14

         Original Interest Accrual Date        September 9, 2003
                         Interest Rate:        4.375%
                       Stated Maturity:        October 1, 2008
                Interest Payment Dates:        April 1 and October 1
                  Regular Record Dates:        March 15 and September 15

                    This Security is not a Discount Security

              within the meaning of the within-mentioned Indenture

Principal Amount                                               Registered No.
$                                                              CUSIP 744448 BW 0

         PUBLIC SERVICE COMPANY OF COLORADO, a corporation duly organized and
existing under the laws of the State of Colorado (herein called the "Company,"
which term includes any successor corporation under the Indenture referred to
below), for value received, hereby promises to pay to

, or registered assigns, the principal sum of

Dollars on the Stated Maturity specified above, and to pay interest thereon from
the Original Interest Accrual Date specified above or from the most recent
Interest Payment Date to which interest has been paid or duly provided for,
semi-annually in arrears on the Interest Payment Dates specified above in each
year, commencing April 1, 2004, and at Maturity, at the Interest Rate per annum
specified above, until the principal hereof is paid or duly provided for. The
interest so payable, and paid or duly provided for, on any Interest Payment Date
shall, as provided in such Indenture, be paid to the Person in whose name this
Security (or one or more Predecessor Securities) is registered at the close of
business on the Regular Record Date specified above (whether or not a Business
Day) next preceding such Interest Payment Date. Notwithstanding the foregoing,
interest payable at Maturity shall be paid to the Person to whom principal shall
be paid. Except as otherwise provided in said Indenture, any such interest not
so paid or duly provided for shall forthwith cease to be payable to the Holder
on such Regular Record Date and may either be paid to the Person in whose name
this Security (or one or more Predecessor Securities) is registered at the close
of business on a Special Record Date for the payment of such Defaulted Interest
to be fixed by the Trustee, notice of which shall be given to Holders of
Securities of this series not less than 15 days prior to such Special Record
Date, or be paid in such other manner as permitted by the Indenture.

                                   EXHIBIT A-1



         Payment of the principal of this Security and interest hereon at
Maturity shall be made upon presentation of this Security at the Corporate Trust
Office of U.S. Bank Trust National Association, in New York, New York or at such
other office or agency as may be designated for such purpose by the Company from
time to time. Payment of interest on this Security (other than interest at
Maturity) shall be made by check mailed to the address of the Person entitled
thereto as such address shall appear in the Security Register, except that if
such Person shall be a securities depositary, such payment may be made by such
other means in lieu of check as shall be agreed upon by the Company, the Trustee
and such Person. Payment of the principal of and interest on this Security, as
aforesaid, shall be made in such coin or currency of the United States of
America as at the time of payment shall be legal tender for the payment of
public and private debts.

         This Security is one of a duly authorized issue of securities of the
Company (herein called the "Securities"), issued and issuable in one or more
series under and equally secured by an Indenture, dated as of October 1, 1993
(such Indenture as originally executed and delivered and as supplemented or
amended from time to time thereafter, together with any constituent instruments
establishing the terms of particular Securities, being herein called the
"Indenture"), between the Company and U.S. Bank Trust National Association
(formerly First Trust of New York, National Association) as successor trustee
(herein called the "Trustee," which term includes any successor trustee under
the Indenture), to which Indenture and all indentures supplemental thereto
reference is hereby made for a description of the property mortgaged, pledged
and held in trust, the nature and extent of the security and the respective
rights, limitations of rights, duties and immunities of the Company, the Trustee
and the Holders of the Securities thereunder and of the terms and conditions
upon which the Securities are, and are to be, authenticated and delivered and
secured. The acceptance of this Security shall be deemed to constitute the
consent and agreement by the Holder hereof to all of the terms and provisions of
the Indenture. This Security is one of the series designated above.

         If any Interest Payment Date or the Stated Maturity shall not be a
Business Day (as hereinafter defined), payment of the amounts due on this
Security on such date may be made on the next succeeding Business Day; and, if
such payment is made or duly provided for on such Business Day, no interest
shall accrue on such amounts for the period from and after such Interest Payment
Date or Stated Maturity, as the case may be, to such Business Day.

         This Security shall be redeemable at the option of the Company at any
time prior to Maturity, in whole or in part, at a redemption price equal to the
greater of (i) 100% of the principal amount hereof to be redeemed, or (ii) the
sum of the present values of the remaining scheduled payments of principal and
interest on this Security to be redeemed, discounted to the Redemption Date on a
semi-annual basis (assuming a 360-day year consisting of twelve 30-day months)
at the Treasury Yield plus 15 basis points, plus in each case, accrued and
unpaid interest to the Redemption Date. For purposes hereof, the following
defined terms shall have the meaning ascribed to them:

         "Treasury Yield" means, for any Redemption Date, the rate per annum
equal to the semi-annual equivalent yield to maturity of the Comparable Treasury
Issue, assuming a price for the Comparable Treasury Issue (expressed as a
percentage of its principal amount) equal to the Comparable Treasury Price for
the Redemption Date.

         "Comparable Treasury Issue" means the United States Treasury security
selected by the Independent Investment Banker as having a maturity comparable to
the remaining term of the Securities of Series No. 14 that would be utilized, at
the time of selection and in accordance with customary financial practice, in
pricing new issues of corporate debt securities of comparable maturity to the
remaining term of the Securities of Series No. 14.

                                   EXHIBIT A-2



         "Comparable Treasury Price" means, for any Redemption Date, (i) the
average of the bid and asked prices for the Comparable Treasury Issue (expressed
in each case as a percentage of its principal amount) on the third Business Day
preceding the Redemption Date, as set forth in the daily statistical release (or
any successor release) published by the Federal Reserve Bank of New York and
designated "Composite 3:30 p.m. Quotations for U.S. Government Securities" or
(ii) if that release (or any successor release) is not published or does not
contain those prices on that Business Day, (A) the average of the Reference
Treasury Dealer Quotations for the Redemption Date, after excluding the highest
and lowest Reference Treasury Dealer Quotations for the Redemption Date, or (B)
if the Trustee obtains fewer than four Reference Treasury Dealer Quotations, the
average of all of the Quotations.

         "Independent Investment Banker" means Banc One Capital Markets, Inc. or
its successor or, if such firm or its successor is unwilling or unable to select
the Comparable Treasury Issue, one of the remaining Reference Treasury Dealers
appointed by the Trustee after consultation with the Company.

         "Reference Treasury Dealer" means (i) each of Banc One Capital Markets,
Inc., McDonald Investments Inc. or UBS Securities LLC and any other Primary
Treasury Dealer designated by, and not affiliated with, Banc One Capital
Markets, Inc., McDonald Investments Inc. or UBS Securities LLC and their
respective successors, provided, however, that if any of the foregoing or any of
its designees ceases to be a Primary Treasury Dealer, the Company will appoint
another Primary Treasury Dealer as a substitute and (ii) any other Primary
Treasury Dealer selected by the Company.

         "Primary Treasury Dealer" means any primary U.S. Government securities
dealer in the United States.

         "Reference Treasury Dealer Quotations" means, for each Reference
Treasury Dealer and any Redemption Date, the average, as determined by the
Independent Investment Banker, of the bid and asked prices for the Comparable
Treasury Issue (expressed in each case as a percentage of its principal amount)
quoted in writing to the Independent Investment Banker by the Reference Treasury
Dealer at 5:00 p.m. on the third Business Day preceding the Redemption Date.

         If an Event of Default shall occur and be continuing, the principal of
this Security may be declared due and payable in the manner and with the effect
provided in the Indenture.

         The Indenture permits, with certain exceptions as therein provided, the
Trustee to enter into one or more supplemental indentures for the purpose of
adding any provisions to, or changing in any manner or eliminating any of the
provisions of, the Indenture with the consent of the Holders of not less than a
majority in aggregate principal amount of the Securities of all series then
Outstanding under the Indenture, considered as one class; provided, however,
that if there shall be Securities of more than one series Outstanding under the
Indenture and if a proposed supplemental indenture shall directly affect the
rights of the Holders of Securities of one or more, but less than all, of such
series, then the consent only of the Holders of a majority in aggregate
principal amount of the Outstanding Securities of all series so directly
affected, considered as one class, shall be required; and provided, further,
that if the Securities of any series shall have been issued in more than one
Tranche and if the proposed supplemental indenture shall directly affect the
rights of the Holders of Securities of one or more, but less than all, of such
Tranches, then the consent only of the Holders of a majority in aggregate
principal amount of the Outstanding Securities of all Tranches so directly
affected, considered as one class, shall be required; and provided, further,
that the Indenture permits the Trustee to enter into one or more supplemental
indentures for limited purposes without the consent of any Holders of
Securities. The Indenture also contains provisions permitting the Holders of a
majority in principal amount of the Securities then Outstanding, on behalf of
the Holders of all Securities, to waive compliance by the Company with certain
provisions of the Indenture and certain past defaults under the Indenture and
their consequences. Any such consent or

                                  EXHIBIT A-3



waiver by the Holder of this Security shall be conclusive and binding upon such
Holder and upon all future Holders of this Security and of any Security issued
upon the registration of transfer hereof or in exchange therefor or in lieu
hereof, whether or not notation of such consent or waiver is made upon this
Security.

         As provided in the Indenture and subject to certain limitations therein
set forth, this Security or any portion of the principal amount hereof will be
deemed to have been paid for all purposes of the Indenture and to be no longer
Outstanding thereunder, and, at the election of the Company, the Company's
entire indebtedness in respect thereof will be satisfied and discharged, if
there has been irrevocably deposited with the Trustee or any Paying Agent (other
than the Company), in trust, money in an amount which will be sufficient and/or
Eligible Obligations, the principal of and interest on which when due, without
regard to any reinvestment thereof, will provide moneys which, together with
moneys so deposited, will be sufficient, to pay when due the principal of and
interest on this Security when due.

         As provided in the Indenture and subject to certain limitations therein
set forth, the transfer of this Security is registrable in the Security
Register, upon surrender of this Security for registration of transfer at the
office of U.S. Bank Trust National Association, in New York, New York or such
other office or agency as may be designated by the Company from time to time,
duly endorsed by, or accompanied by a written instrument of transfer in form
satisfactory to the Company and the Security Registrar duly executed by, the
Holder hereof or his attorney duly authorized in writing, and thereupon one or
more new Securities of this series of authorized denominations and of like tenor
and aggregate principal amount, will be issued to the designated transferee or
transferees.

         The Securities of this series are issuable only as registered
Securities, without coupons, and in denominations of $1,000 and integral
multiples thereof. As provided in the Indenture and subject to certain
limitations therein set forth, Securities of this series are exchangeable for a
like aggregate principal amount of Securities of the same series, of any
authorized denominations, as requested by the Holder surrendering the same, and
of like tenor upon surrender of the Security or Securities to be exchanged at
the office of U.S. Bank Trust National Association, in New York, New York or
such other office or agency as may be designated by the Company from time to
time.

         No service charge shall be made for any such registration of transfer
or exchange, but the Company may require payment of a sum sufficient to cover
any tax or other governmental charge payable in connection therewith.

         Prior to due presentment of this Security for registration of transfer,
the Company, the Trustee and any agent of the Company or the Trustee may treat
the Person in whose name this Security is registered as the absolute owner
hereof for all purposes, whether or not this Security be overdue, and neither
the Company, the Trustee nor any such agent shall be affected by notice to the
contrary.

         The Indenture and the Securities shall be governed by and construed in
accordance with the laws of the State of New York.

         As used herein "Business Day" means any day, other than a Saturday or
Sunday, which is not a day on which banking institutions or trust companies in
The City of New York, New York or other city in which is located any office or
agency maintained for the payment of principal or interest on this Security, are
authorized or required by law, regulation or executive order to remain closed.
All other terms used in this Security which are defined in the Indenture shall
have the meanings assigned to them in the Indenture.

                                  EXHIBIT A-4



         As provided in the Indenture, no recourse shall be had for the payment
of the principal of or interest on any Securities, or any part thereof, or for
any claim based thereon or otherwise in respect thereof, or of the indebtedness
represented thereby, or upon any obligation, covenant or agreement under the
Indenture, against, and no personal liability whatsoever shall attach to, or be
incurred by, any incorporator, shareholder, officer or director, as such, past,
present or future of the Company or of any predecessor or successor corporation
(either directly or through the Company or a predecessor or successor
corporation), whether by virtue of any constitutional provision, statute or rule
of law, or by the enforcement of any assessment or penalty or otherwise; it
being expressly agreed and understood that the Indenture and all the Securities
are solely corporate obligations and that any such personal liability is hereby
expressly waived and released as a condition of, and as part of the
consideration for, the execution of the Indenture and the issuance of the
Securities.

         Unless the certificate of authentication hereon has been executed by
the Trustee or an Authenticating Agent by manual signature, this Security shall
not be entitled to any benefit under the Indenture or be valid or obligatory for
any purpose.

                                  EXHIBIT A-5



         IN WITNESS WHEREOF, the Company has caused this instrument to be duly
executed and its corporate seal to be hereunto affixed and attested.

                                      PUBLIC SERVICE COMPANY OF COLORADO

                                      By: ______________________________________
                                               [Title]

Attest: ______________________________
              [Title]

                          CERTIFICATE OF AUTHENTICATION

         This is one of the Securities of the series designated therein referred
to in the within-mentioned Indenture.

Dated: _______________________________

   U.S. BANK TRUST                    OR                      U.S. BANK TRUST
NATIONAL ASSOCIATION,                                      NATIONAL ASSOCIATION,
     as Trustee                                                 as Trustee

By:_____________________________                  By:___________________________
       Authorized Officer                             AS AUTHENTICATING AGENT

                                                  By:___________________________
                                                         Authorized Officer

         UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF
THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), TO THE COMPANY OR
ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE, OR PAYMENT, AND ANY
CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR IN SUCH OTHER NAME
AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE
TO CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE, OR OTHER USE HEREOF FOR VALUE OR
OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER
HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

         THIS SECURITY MAY NOT BE TRANSFERRED OR EXCHANGED, NOR MAY ANY
PURPORTED TRANSFER BE REGISTERED, EXCEPT (i) THIS SECURITY MAY BE TRANSFERRED IN
WHOLE, AND APPROPRIATE REGISTRATION OF TRANSFER EFFECTED, IF SUCH TRANSFER IS BY
CEDE & CO., AS NOMINEE FOR THE DEPOSITORY TRUST COMPANY (THE "DEPOSITARY"), TO
THE DEPOSITARY, OR BY THE DEPOSITARY TO ANOTHER NOMINEE THEREOF, OR BY ANY
NOMINEE OF THE DEPOSITARY TO ANY OTHER NOMINEE THEREOF, OR BY THE DEPOSITARY OR
ANY NOMINEE THEREOF TO ANY SUCCESSOR SECURITIES DEPOSITARY OR ANY NOMINEE
THEREOF; AND (ii) THIS SECURITY MAY BE EXCHANGED FOR DEFINITIVE SECURITIES
REGISTERED IN THE RESPECTIVE NAMES OF THE BENEFICIAL HOLDERS HEREOF, AND
THEREAFTER SHALL BE TRANSFERABLE WITHOUT RESTRICTIONS IF: (A) THE DEPOSITARY, OR
ANY SUCCESSOR SECURITIES DEPOSITARY, SHALL HAVE NOTIFIED THE COMPANY AND THE
TRUSTEE THAT IT IS UNWILLING OR UNABLE TO CONTINUE TO ACT AS SECURITIES
DEPOSITARY WITH RESPECT TO THE SECURITIES AND THE TRUSTEE SHALL NOT HAVE BEEN
NOTIFIED BY THE COMPANY WITHIN NINETY (90) DAYS OF THE IDENTITY OF A SUCCESSOR

                                  EXHIBIT A-6



SECURITIES DEPOSITARY WITH RESPECT TO THE SECURITIES; OR (B) THE COMPANY SHALL
HAVE DELIVERED TO THE TRUSTEE A COMPANY ORDER TO THE EFFECT THAT THE SECURITIES
SHALL BE SO EXCHANGEABLE ON AND AFTER A DATE SPECIFIED THEREIN.

                                  EXHIBIT A-7


   FOR VALUE RECEIVED the undersigned hereby sells, assigns and transfers unto

________________________________________________________________________________

     [please insert social security or other identifying number of assignee]

________________________________________________________________________________
            [please print or typewrite name and address of assignee]

________________________________________________________________________________

the within Security of PUBLIC SERVICE COMPANY OF COLORADO and does hereby
irrevocably constitute and appoint __________________________________ ,
Attorney, to transfer said Security on the books of the within-mentioned
Company, with full power of substitution in the premises.

Dated:____________________________

                  ___________________________________________

         Notice: The signature to this assignment must correspond with the name
         as written upon the face of the Security in every particular without
         alteration or enlargement or any change whatsoever.

                                  EXHIBIT A-8


                                                                       EXHIBIT B

                                FORM OF SECURITY

                   (See legend at the end of this Security for
                            restrictions on transfer)

                       PUBLIC SERVICE COMPANY OF COLORADO
                   First Collateral Trust Bond, Series No. 15

         Original Interest Accrual Date          September 9, 2003
                         Interest Rate:          5.50%
                       Stated Maturity:          April 1, 2014
                Interest Payment Dates:          April 1 and October 1
                  Regular Record Dates:          March 15 and September 15

                    This Security is not a Discount Security
              within the meaning of the within-mentioned Indenture

                 -----------------------------------------

Principal Amount                                               Registered No.
$                                                              CUSIP 744448 BX 8

         PUBLIC SERVICE COMPANY OF COLORADO, a corporation duly organized and
existing under the laws of the State of Colorado (herein called the "Company,"
which term includes any successor corporation under the Indenture referred to
below), for value received, hereby promises to pay to

, or registered assigns, the principal sum of

Dollars on the Stated Maturity specified above, and to pay interest thereon from
the Original Interest Accrual Date specified above or from the most recent
Interest Payment Date to which interest has been paid or duly provided for,
semi-annually in arrears on the Interest Payment Dates specified above in each
year, commencing April 1, 2004, and at Maturity, at the Interest Rate per annum
specified above, until the principal hereof is paid or duly provided for. The
interest so payable, and paid or duly provided for, on any Interest Payment Date
shall, as provided in such Indenture, be paid to the Person in whose name this
Security (or one or more Predecessor Securities) is registered at the close of
business on the Regular Record Date specified above (whether or not a Business
Day) next preceding such Interest Payment Date. Notwithstanding the foregoing,
interest payable at Maturity shall be paid to the Person to whom principal shall
be paid. Except as otherwise provided in said Indenture, any such interest not
so paid or duly provided for shall forthwith cease to be payable to the Holder
on such Regular Record Date and may either be paid to the Person in whose name
this Security (or one or more Predecessor Securities) is registered at the close
of business on a Special Record Date for the payment of such Defaulted Interest
to

                                  EXHIBIT B-1



be fixed by the Trustee, notice of which shall be given to Holders of Securities
of this series not less than 15 days prior to such Special Record Date, or be
paid in such other manner as permitted by the Indenture.

         Payment of the principal of this Security and interest hereon at
Maturity shall be made upon presentation of this Security at the Corporate Trust
Office of U.S. Bank Trust National Association, in New York, New York or at such
other office or agency as may be designated for such purpose by the Company from
time to time. Payment of interest on this Security (other than interest at
Maturity) shall be made by check mailed to the address of the Person entitled
thereto as such address shall appear in the Security Register, except that if
such Person shall be a securities depositary, such payment may be made by such
other means in lieu of check as shall be agreed upon by the Company, the Trustee
and such Person. Payment of the principal of and interest on this Security, as
aforesaid, shall be made in such coin or currency of the United States of
America as at the time of payment shall be legal tender for the payment of
public and private debts.

         This Security is one of a duly authorized issue of securities of the
Company (herein called the "Securities"), issued and issuable in one or more
series under and equally secured by an Indenture, dated as of October 1, 1993
(such Indenture as originally executed and delivered and as supplemented or
amended from time to time thereafter, together with any constituent instruments
establishing the terms of particular Securities, being herein called the
"Indenture"), between the Company and U.S. Bank Trust National Association
(formerly First Trust of New York, National Association) as successor trustee
(herein called the "Trustee," which term includes any successor trustee under
the Indenture), to which Indenture and all indentures supplemental thereto
reference is hereby made for a description of the property mortgaged, pledged
and held in trust, the nature and extent of the security and the respective
rights, limitations of rights, duties and immunities of the Company, the Trustee
and the Holders of the Securities thereunder and of the terms and conditions
upon which the Securities are, and are to be, authenticated and delivered and
secured. The acceptance of this Security shall be deemed to constitute the
consent and agreement by the Holder hereof to all of the terms and provisions of
the Indenture. This Security is one of the series designated above.

         If any Interest Payment Date or the Stated Maturity shall not be a
Business Day (as hereinafter defined), payment of the amounts due on this
Security on such date may be made on the next succeeding Business Day; and, if
such payment is made or duly provided for on such Business Day, no interest
shall accrue on such amounts for the period from and after such Interest Payment
Date or Stated Maturity, as the case may be, to such Business Day.

         This Security shall be redeemable at the option of the Company at any
time prior to Maturity, in whole or in part, at a redemption price equal to the
greater of (i) 100% of the principal amount hereof to be redeemed, or (ii) the
sum of the present values of the remaining scheduled payments of principal and
interest on this Security to be redeemed, discounted to the Redemption Date on a
semi-annual basis (assuming a 360-day year consisting of twelve 30-day months)
at the Treasury Yield plus 20 basis points, plus in each case, accrued and
unpaid interest to the Redemption Date. For purposes hereof, the following
defined terms shall have the meaning ascribed to them:

         "Treasury Yield" means, for any Redemption Date, the rate per annum
equal to the semi-annual equivalent yield to maturity of the Comparable Treasury
Issue, assuming a price for the Comparable Treasury Issue (expressed as a
percentage of its principal amount) equal to the Comparable Treasury Price for
the Redemption Date.

         "Comparable Treasury Issue" means the United States Treasury security
selected by the Independent Investment Banker as having a maturity comparable to
the remaining term of the Securities of Series No. 15 that would be utilized, at
the time of selection and in accordance with customary

                                  EXHIBIT B-2



financial practice, in pricing new issues of corporate debt securities of
comparable maturity to the remaining term of the Securities of Series No. 15.

         "Comparable Treasury Price" means, for any Redemption Date, (i) the
average of the bid and asked prices for the Comparable Treasury Issue (expressed
in each case as a percentage of its principal amount) on the third Business Day
preceding the Redemption Date, as set forth in the daily statistical release (or
any successor release) published by the Federal Reserve Bank of New York and
designated "Composite 3:30 p.m. Quotations for U.S. Government Securities" or
(ii) if that release (or any successor release) is not published or does not
contain those prices on that Business Day, (A) the average of the Reference
Treasury Dealer Quotations for the Redemption Date, after excluding the highest
and lowest Reference Treasury Dealer Quotations for the Redemption Date, or (B)
if the Trustee obtains fewer than four Reference Treasury Dealer Quotations, the
average of all of the Quotations.

         "Independent Investment Banker" means Banc One Capital Markets, Inc. or
its successor or, if such firm or its successor is unwilling or unable to select
the Comparable Treasury Issue, one of the remaining Reference Treasury Dealers
appointed by the Trustee after consultation with the Company.

         "Reference Treasury Dealer" means (i) each of Banc One Capital Markets,
Inc., McDonald Investments Inc. or UBS Securities LLC and any other Primary
Treasury Dealer designated by, and not affiliated with, Banc One Capital
Markets, Inc., McDonald Investments Inc. or UBS Securities LLC and their
respective successors, provided, however, that if any of the foregoing or any of
its designees ceases to be a Primary Treasury Dealer, the Company will appoint
another Primary Treasury Dealer as a substitute and (ii) any other Primary
Treasury Dealer selected by the Company.

         "Primary Treasury Dealer" means any primary U.S. Government securities
dealer in the United States.

         "Reference Treasury Dealer Quotations" means, for each Reference
Treasury Dealer and any Redemption Date, the average, as determined by the
Independent Investment Banker, of the bid and asked prices for the Comparable
Treasury Issue (expressed in each case as a percentage of its principal amount)
quoted in writing to the Independent Investment Banker by the Reference Treasury
Dealer at 5:00 p.m. on the third Business Day preceding the Redemption Date.

         If an Event of Default shall occur and be continuing, the principal of
this Security may be declared due and payable in the manner and with the effect
provided in the Indenture.

         The Indenture permits, with certain exceptions as therein provided, the
Trustee to enter into one or more supplemental indentures for the purpose of
adding any provisions to, or changing in any manner or eliminating any of the
provisions of, the Indenture with the consent of the Holders of not less than a
majority in aggregate principal amount of the Securities of all series then
Outstanding under the Indenture, considered as one class; provided, however,
that if there shall be Securities of more than one series Outstanding under the
Indenture and if a proposed supplemental indenture shall directly affect the
rights of the Holders of Securities of one or more, but less than all, of such
series, then the consent only of the Holders of a majority in aggregate
principal amount of the Outstanding Securities of all series so directly
affected, considered as one class, shall be required; and provided, further,
that if the Securities of any series shall have been issued in more than one
Tranche and if the proposed supplemental indenture shall directly affect the
rights of the Holders of Securities of one or more, but less than all, of such
Tranches, then the consent only of the Holders of a majority in aggregate
principal amount of the Outstanding Securities of all Tranches so directly
affected, considered as one class, shall be required; and provided, further,
that the Indenture permits the Trustee to enter into one or more supplemental
indentures for limited purposes without the consent of any Holders of
Securities. The Indenture also contains

                                  EXHIBIT B-3



provisions permitting the Holders of a majority in principal amount of the
Securities then Outstanding, on behalf of the Holders of all Securities, to
waive compliance by the Company with certain provisions of the Indenture and
certain past defaults under the Indenture and their consequences. Any such
consent or waiver by the Holder of this Security shall be conclusive and binding
upon such Holder and upon all future Holders of this Security and of any
Security issued upon the registration of transfer hereof or in exchange therefor
or in lieu hereof, whether or not notation of such consent or waiver is made
upon this Security.

         As provided in the Indenture and subject to certain limitations therein
set forth, this Security or any portion of the principal amount hereof will be
deemed to have been paid for all purposes of the Indenture and to be no longer
Outstanding thereunder, and, at the election of the Company, the Company's
entire indebtedness in respect thereof will be satisfied and discharged, if
there has been irrevocably deposited with the Trustee or any Paying Agent (other
than the Company), in trust, money in an amount which will be sufficient and/or
Eligible Obligations, the principal of and interest on which when due, without
regard to any reinvestment thereof, will provide moneys which, together with
moneys so deposited, will be sufficient, to pay when due the principal of and
interest on this Security when due.

         As provided in the Indenture and subject to certain limitations therein
set forth, the transfer of this Security is registrable in the Security
Register, upon surrender of this Security for registration of transfer at the
office of U.S. Bank Trust National Association, in New York, New York or such
other office or agency as may be designated by the Company from time to time,
duly endorsed by, or accompanied by a written instrument of transfer in form
satisfactory to the Company and the Security Registrar duly executed by, the
Holder hereof or his attorney duly authorized in writing, and thereupon one or
more new Securities of this series of authorized denominations and of like tenor
and aggregate principal amount, will be issued to the designated transferee or
transferees.

         The Securities of this series are issuable only as registered
Securities, without coupons, and in denominations of $1,000 and integral
multiples thereof. As provided in the Indenture and subject to certain
limitations therein set forth, Securities of this series are exchangeable for a
like aggregate principal amount of Securities of the same series, of any
authorized denominations, as requested by the Holder surrendering the same, and
of like tenor upon surrender of the Security or Securities to be exchanged at
the office of U.S. Bank Trust National Association, in New York, New York or
such other office or agency as may be designated by the Company from time to
time.

         No service charge shall be made for any such registration of transfer
or exchange, but the Company may require payment of a sum sufficient to cover
any tax or other governmental charge payable in connection therewith.

         Prior to due presentment of this Security for registration of transfer,
the Company, the Trustee and any agent of the Company or the Trustee may treat
the Person in whose name this Security is registered as the absolute owner
hereof for all purposes, whether or not this Security be overdue, and neither
the Company, the Trustee nor any such agent shall be affected by notice to the
contrary.

         The Indenture and the Securities shall be governed by and construed in
accordance with the laws of the State of New York.

         As used herein "Business Day" means any day, other than a Saturday or
Sunday, which is not a day on which banking institutions or trust companies in
The City of New York, New York or other city in which is located any office or
agency maintained for the payment of principal or interest on this Security, are
authorized or required by law, regulation or executive order to remain closed.
All other terms used in

                                  EXHIBIT B-4



this Security which are defined in the Indenture shall have the meanings
assigned to them in the Indenture.

         As provided in the Indenture, no recourse shall be had for the payment
of the principal of or interest on any Securities, or any part thereof, or for
any claim based thereon or otherwise in respect thereof, or of the indebtedness
represented thereby, or upon any obligation, covenant or agreement under the
Indenture, against, and no personal liability whatsoever shall attach to, or be
incurred by, any incorporator, shareholder, officer or director, as such, past,
present or future of the Company or of any predecessor or successor corporation
(either directly or through the Company or a predecessor or successor
corporation), whether by virtue of any constitutional provision, statute or rule
of law, or by the enforcement of any assessment or penalty or otherwise; it
being expressly agreed and understood that the Indenture and all the Securities
are solely corporate obligations and that any such personal liability is hereby
expressly waived and released as a condition of, and as part of the
consideration for, the execution of the Indenture and the issuance of the
Securities.

         Unless the certificate of authentication hereon has been executed by
the Trustee or an Authenticating Agent by manual signature, this Security shall
not be entitled to any benefit under the Indenture or be valid or obligatory for
any purpose.

                                  EXHIBIT B-5



         IN WITNESS WHEREOF, the Company has caused this instrument to be duly
executed and its corporate seal to be hereunto affixed and attested.

                                      PUBLIC SERVICE COMPANY OF COLORADO

                                      By:_______________________________________
                                              [Title]

Attest:_______________________________
                [Title]

                          CERTIFICATE OF AUTHENTICATION

         This is one of the Securities of the series designated therein referred
to in the within-mentioned Indenture.

Dated:________________________________

   U.S. BANK TRUST                    OR                      U.S. BANK TRUST
NATIONAL ASSOCIATION,                                      NATIONAL ASSOCIATION,
     as Trustee                                                 as Trustee

By:_____________________________                 By:____________________________
         Authorized Officer                          AS AUTHENTICATING AGENT

                                                 By:____________________________
                                                        Authorized Officer

         UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF
THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), TO THE COMPANY OR
ITS AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE, OR PAYMENT, AND ANY
CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR IN SUCH OTHER NAME
AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE
TO CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE, OR OTHER USE HEREOF FOR VALUE OR
OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER
HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

         THIS SECURITY MAY NOT BE TRANSFERRED OR EXCHANGED, NOR MAY ANY
PURPORTED TRANSFER BE REGISTERED, EXCEPT (i) THIS SECURITY MAY BE TRANSFERRED IN
WHOLE, AND APPROPRIATE REGISTRATION OF TRANSFER EFFECTED, IF SUCH TRANSFER IS BY
CEDE & CO., AS NOMINEE FOR THE DEPOSITORY TRUST COMPANY (THE "DEPOSITARY"), TO
THE DEPOSITARY, OR BY THE DEPOSITARY TO ANOTHER NOMINEE THEREOF, OR BY ANY
NOMINEE OF THE DEPOSITARY TO ANY OTHER NOMINEE THEREOF, OR BY THE DEPOSITARY OR
ANY NOMINEE THEREOF TO ANY SUCCESSOR SECURITIES DEPOSITARY OR ANY NOMINEE
THEREOF; AND (ii) THIS SECURITY MAY BE EXCHANGED FOR DEFINITIVE SECURITIES
REGISTERED IN THE RESPECTIVE NAMES OF THE BENEFICIAL HOLDERS HEREOF, AND
THEREAFTER SHALL BE TRANSFERABLE WITHOUT RESTRICTIONS IF: (A) THE DEPOSITARY, OR
ANY SUCCESSOR SECURITIES DEPOSITARY, SHALL HAVE NOTIFIED THE COMPANY AND THE
TRUSTEE THAT IT IS UNWILLING OR UNABLE TO CONTINUE TO ACT AS SECURITIES
DEPOSITARY WITH RESPECT TO THE SECURITIES AND THE TRUSTEE SHALL NOT HAVE BEEN
NOTIFIED BY THE COMPANY WITHIN NINETY (90) DAYS OF THE IDENTITY OF A SUCCESSOR

                                  EXHIBIT B-6



SECURITIES DEPOSITARY WITH RESPECT TO THE SECURITIES; OR (B) THE COMPANY SHALL
HAVE DELIVERED TO THE TRUSTEE A COMPANY ORDER TO THE EFFECT THAT THE SECURITIES
SHALL BE SO EXCHANGEABLE ON AND AFTER A DATE SPECIFIED THEREIN.

                                  EXHIBIT B-7



  FOR VALUE RECEIVED the undersigned hereby sells, assigns and transfers unto

________________________________________________________________________________

     [please insert social security or other identifying number of assignee]

________________________________________________________________________________
            [please print or typewrite name and address of assignee]

________________________________________________________________________________

the within Security of PUBLIC SERVICE COMPANY OF COLORADO and does hereby
irrevocably constitute and appoint __________________________________ ,
Attorney, to transfer said Security on the books of the within-mentioned
Company, with full power of substitution in the premises.

Dated:___________________________

                    _______________________________________

         Notice: The signature to this assignment must correspond with the name
         as written upon the face of the Security in every particular without
         alteration or enlargement or any change whatsoever.

                                  EXHIBIT B-8


                                                                      SCHEDULE A

                             SUPPLEMENTAL INDENTURES



      DATE OF                                                       PRINCIPAL
   SUPPLEMENTAL                                     PRINCIPAL         AMOUNT
     INDENTURE            SERIES OF BONDS         AMOUNT ISSUED    OUTSTANDING
     ---------            ----------------       --------------    -----------
                                                          
November 1, 1993           Series No. 1            $134,500,000    $134,500,000
January 1, 1994        Series No. 2 due 2001       $102,667,000        None
                               and
                       Series No. 2 due 2024       $110,000,000    $110,000,000
September 2, 1994              None                   None             None
(Appointment of
Successor Trustee)
May 1, 1996                Series No. 3            $125,000,000    $125,000,000
November 1, 1996           Series No. 4            $250,000,000    $175,000,000
February 1, 1997           Series No. 5            $150,000,000        None
April 1, 1998              Series No. 6            $250,000,000        None
August 15, 2002            Series No. 7            $ 48,750,000    $ 48,750,000
September 1, 2002          Series No. 8            $600,000,000        None
September 15, 2002         Series No. 9            $530,000,000        None
April 1, 2003              Series No. 10           $600,000,000    $600,000,000
March 1, 2003              Series No. 11           $250,000,000    $250,000,000
May 1, 2003                Series No. 13           $350,000,000    $350,000,000


                                  SCHEDULE A-1