SC 13D/A

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D/A

(Amendment No.7 )

Under the Securities Exchange Act of 1934

Plug Power, Inc.

(Name of Issuer)

Common Stock (par value $0.01 per share)

(Title of Class of Securities)

72919P103

(CUSIP Number)

Catherine S. Hill, Esq.

Mechanical Technology Incorporated

431 New Karner Road

Albany, New York 12205

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

December 20, 2002

(Date of event which Requires Filing of this Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition which is the subject of this Schedule 13D, and is filing this schedule because of Rule 13d-1(b)(3) or (4), check the following box: 

Note: Six copies of this statement, including all exhibits, should be filed with the Commission.

See Rule 13d-1(a) for other parties to whom copies are to be sent.

* The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

CUSIP No. 72919P103
1	Name of Reporting Person S.S. or I.R.S. Identification No. of Above Person Mechanical Technology Incorporated I.R.S. Identification No. 141462255
2	Check the Appropriate Box if a Member of a Group	(a) [ ] (b) [ ]
3	SEC Use Only
4	Source of Funds OO
5	Check if Disclosure of Legal Proceedings is Required Pursuant to Items 2(d) or 2(e)	[ ]
6	Citizenship or Place of Organization State of New York
		7	Solve Voting Power	8,108,227
Number of Shares Beneficially Owned by Reporting Person With		8	Shared Voting Power	0
		9	Sole Dispositive Power	8,108,227
		10	Shared Dispositive Power	0
11	Aggregate Amount Beneficially Owned by Each Reporting Person			8,108,227
12	Check Box if the Aggregate Amount in Row (11) Excludes Certain Shares	[ ]
13	Percent of Class Represented Amount in Row (11)	15.94%
14	Type of Reporting Person	CO

Schedule 13D/A

This Amendment No. 7 to the Schedule 13D amends and supplements the Schedule 13D originally filed on December 11, 2000 (the "Schedule 13D") by Mechanical Technology Inc., a New York Corporation. Unless otherwise defined herein, all capitalized terms used herein have the respective meanings given to such terms in the Schedule 13D.

Item 4. Purpose of Transaction.

Item 4 of the Schedule 13D is hereby amended to read as follows:

The business conducted by the Issuer was initially developed by MTI prior to June 1997, and was contributed to Plug Power, LLC (the predecessor of the Company) in exchange for equity interests. Based upon the historical development of the business of the Issuer and the significant continuous equity ownership by MTI of Plug Power, LLC and the Issuer, MTI may be deemed to have influence over the management or policies of the Issuer.

On December 20, 2002, MTI entered into an exchange transaction with First Albany Companies Inc. (FAC) where 8 million shares of MTI common stock owned by FAC were exchanged for 2,721,088 shares of Plug Power common stock owned by MTI.

On December 17, 2001, MTI entered into a plan under Rule 10b5-1 (the "Plan") pursuant to which MTI will sell shares of Common Stock of the Issuer. The Plan provides for the sale of, and MTI intends to sell, up to 1.2 million shares and 2 million shares of Common Stock of the Issuer during calendar 2002 and calendar 2003, respectively. As of December 20, 2002, 1,165,000 shares of Common Stock of the Issuer have been sold pursuant to the Plan. Under the terms of the Plan, MTI may terminate the Plan at any time.

In addition to the foregoing, as significant shareholders of Plug Power, MTI may consider, from time to time, (i) the acquisition of additional securities of the Issuer, or the disposition of securities of the Issuer, (ii) an extraordinary corporate transaction, such as a merger, reorganization or liquidation, involving the Issuer or any of its subsidiaries, (iii) a sale or transfer of a material amount of the assets of the Issuer or any of its subsidiaries, (iv) any change in the present board of directors or management of the Issuer, (v) any material change in the present capitalization or dividend policy of the Issuer, (vi) any other material change in the Issuer's business or corporate structure, (vii) changes in the Issuer's charter, bylaws, or instruments corresponding thereto or other actions which may impede the acquisition of control of the Issuer by any person; (viii) causing a class of securities of the Issuer to be delisted from a national securities exchange or to cease to be authorized t o be quoted on an inter-dealer quotation system of a registered national securities association, (ix) causing a class of equity securities of the Issuer to become eligible for termination of a registration pursuant to Section 12(g)(4) of the Exchange Act, or (x) any action similar to any of those enumerated above.

Item 5. Interest in Securities of the Issuer.

Item 5 of the Schedule 13D is hereby amended to read as follows:

As of December 20, 2002:

(a) MTI is the direct and beneficial owner of 8,108,227 shares of the Issuer Common Stock, including shares covered by the Plan, representing 15.94% of the Common Stock outstanding.

(b) MTI has the sole power to vote and sole dispositive power for 8,108,227 shares of the Issuer Common Stock.

(c) During the past sixty (60) days MTI has sold shares of Common Stock of the Issuer, in open market transactions, as follows:

Date	Number of shares	Price per share	Date	Number of shares	Price per share
10/22/02	9,200	$ 5.0888	11/19/02	1,500	$ 5.39
10/23/02	6,300	$ 5.0897	11/20/02	3,000	$ 5.4644
10/24/02	12,500	$ 5.2650	11/21/02	3,000	$ 5.8617
10/28/02	3,500	$ 5.3137	11/25/02	1,500	$ 6.29
10/29/02	34,000	$ 5.8631	11/26/02	2,500	$ 6.6212
10/30/02	2,500	$ 6.4218	11/27/02	4,000	$ 6.8175
10/31/02	2,500	$ 6.1050	12/05/02	3,500	$ 5.6066
11/04/02	5,000	$ 5.9827	12/06/02	4,000	$ 5.4182
11/06/02	5,000	$ 5.8400	12/09/02	4,000	$ 5.3498
11/07/02	1,500	$ 5.7850	12/11/02	3,000	$ 5.6540
11/08/02	3,500	$ 5.5151	12/12/02	5,000	$ 5.6000
11/12/02	3,000	$ 5.0650	12/13/02	5,000	$ 5.516
11/13/02	2,500	$ 5.1474	12/16/02	5,000	$ 5.5463
11/14/02	1,500	$ 5.49	12/17/02	5,000	$ 5.5854
11/15/02	1,500	$ 5.29	12/18/02	5,000	$ 5.2617
11/18/02	1,500	$ 5.355

No other Control Person has purchased or sold any shares of Plug Power Common Stock.

(d) Not applicable.

(e) Not applicable.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, the undersigned certifies that the information set forth in this statement is true, correct and complete.

Dated: December 20, 2002

Mechanical Technology Incorporated

s/Cynthia A. Scheuer

By: Cynthia A. Scheuer

EX-99.17 (AS APPROP)

Exhibit 99.17.1

EXCHANGE AGREEMENT

EXCHANGE AGREEMENT, dated December 20, 2002 (the "Agreement"), by and between FIRST ALBANY COMPANIES INC., a New York corporation ("FAC"), and MECHANICAL TECHNOLOGY INCORPORATED, a New York corporation ("MTI").

WHEREAS, FAC and MTI wish to exchange 8,000,000 shares of common stock, par value $1.00 per share, of MTI owned by FAC (the "MTI Shares") for 2,721,088 shares of common stock, par value $.01 per share, of Plug Power Inc., a Delaware corporation ("Plug Power"), owned by MTI (the "Plug Power Shares") on the terms set forth in this Agreement.

NOW, THEREFORE, in consideration of the foregoing, in reliance upon the representations and warranties contained being made herein, and intending to be legally bound hereby, the parties hereto agree as follows:

1. Exchange of Shares
1. Exchange. Upon the terms of this Agreement and in reliance upon the representations and warranties being made to it herein by the other party hereto, FAC is hereby assigning, transferring and delivering the MTI Shares to MTI, in exchange for the Plug Power Shares, and MTI is hereby assigning, transferring and delivering the Plug Power Shares to FAC, in exchange for the MTI Shares, in each case free and clear of all claims, liens, options, charges, agreements, encumbrances and security interests of whatsoever nature ("Encumbrances").
2. Delivery of Certificate. Simultaneously with the execution hereof, the certificates representing the MTI Shares are being delivered by FAC to MTI, duly endorsed to MTI or with executed stock powers attached, and the certificates representing the Plug Power Shares are being delivered by MTI to FAC, duly endorsed to FAC or with executed stock powers attached.
2. Representation and Warranties of FAC.

FAC hereby represents and warrants to MTI that:

1. Authorization. FAC has full corporate power and authority to enter into and consummate the transactions contemplated by this Agreement, and this Agreement has been duly authorized by all necessary corporate action on the part of FAC and has been approved by its Board of Directors.
2. Execution; Binding Obligation. This Agreement has been duly executed and delivered by FAC and constitutes a legal, valid and binding obligation of FAC enforceable in accordance with its terms, except that enforcement may be limited by bankruptcy, insolvency, reorganization or other similar laws concerning the rights of creditors generally and by general equity principles.
3. Delivery of Title. FAC is the holder of record and the sole beneficial owner of the MTI Shares and, in exchange for the Plug Power Shares in accordance with the provisions of this Agreement, FAC is assigning, transferring and delivering the MTI Shares to MTI, free and clear of all Encumbrances.
4. No Violation. Neither the execution of this Agreement nor the consummation by FAC of the transactions contemplated hereby will (i) result in a violation or breach of, or a conflict with, the organizational or governing instruments of FAC or any agreement, instrument, contract or commitment to which FAC is a party or any order, statute, rule, judgment or governmental regulation applicable to FAC or (ii) require the approval or consent of, or any filing with, any party or governmental authority.
5. No Knowledge. FAC is not aware of any facts material to the business, results of operations, assets, liabilities or financial condition of Plug Power or MTI that are not contained in the filings with the Securities and Exchange Commission (the "SEC") of Plug Power or MTI, and it has no knowledge of a material change in the business or prospects of either Plug Power or MTI since the date of each company's most recent quarterly report on Form 10-Q filed with the SEC.
3. Representations and Warranties of MTI.

MTI represents and warrants to FAC that:

1. Authorization. MTI has full corporate power and authority to enter into and consummate the transactions contemplated by this Agreement and this Agreement has been duly authorized by all necessary corporate action on the part of MTI and has been approved by its Board of Directors in accordance with Section 713 of the Business Corporation Law of the State of New York.
2. Execution; Binding Obligation. This Agreement has been duly executed and delivered by MTI and constitutes a legal, valid and binding obligation of MTI enforceable in accordance with its terms, except that enforcement may be limited by bankruptcy, insolvency, reorganization or other similar laws concerning the right of creditors generally and by general equity principles.
3. Delivery of Title. MTI is the holder of record and the sole beneficial owner of the Plug Power Shares and, in exchange for the MTI Shares in accordance with the provisions of this Agreement, MTI is assigning, transferring and delivering the Plug Power Shares to FAC, free and clear of all Encumbrances.
5. No Violation. Neither the execution of this Agreement nor the consummation by MTI of the transactions contemplated hereby will (i) result in a violation or breach of, or a conflict with, the organization or governing instruments of MTI or any agreement, instrument, contract or commitment to which MTI is a party or any order, statute, rule, judgment or governmental regulation applicable to MTI or (ii) require the approval or consent of, or any filing with, any party or governmental authority.
6. No Knowledge. MTI is not aware of any facts material to the business, results of operations, assets, liabilities or financial condition of Plug Power or MTI that are not contained in the filings with the Securities and Exchange Commission (the "SEC") of Plug Power or MTI, and there has been no material change in the business or prospects of MTI, nor does it have any knowledge of a material change in the business or prospects of Plug Power, since the date of each company's most recent quarterly report on Form 10-Q filed with the SEC.
4. Miscellaneous.
1. Public Announcements. FAC and MTI agree that they shall issue a mutually agreeable press release following the consummation of the transactions contemplated by this Agreement. FAC and MTI also agree that neither will, nor will their respective agents, make any other public announcement with respect to this Agreement or the transactions contemplated hereby, except as required by applicable law, and no such public announcement shall be made without the prior consent of the other party.
2. Expenses. Each party hereto will bear its own expenses in connection with the transactions contemplated by this Agreement.
3. Governing Law. This Agreement shall be governed and construed in accordance with the laws of the State of New York without regard to its principles of conflicts of law.
4. Counterparts. This Agreement may be executed in counterparts, each of which shall be deemed to be an original, and all of which shall constitute one and the same document.
5. Entire Agreement, Etc. This Agreement (i) constitutes the entire understanding of the parties hereto as the subject matter hereof and supercedes any prior understanding or agreement, (ii) will be binding upon, inure to the benefit of, and be enforceable by, the parties hereto, their respective successors and permitted assigns and (iii) shall not be assignable without the written consent of the parties hereto.

IN WITNESS WHEREOF, the duly authorized officers of FAC and MTI have executed this Agreement as of the date first above written.

FIRST ALBANY COMPANIES INC.

By: s/Hugh A. Johnson, Jr.

Name: Hugh A. Johnson, Jr.

Title: Senior Vice President and Chief Investment Officer

MECHANICAL TECHNOLOGY INCORPORATED

By:s/Cynthia A. Scheuer

Name: Cynthia A. Scheuer

Title: Vice President and Chief Financial Officer