Exhibit 4.17

THIRD SUPPLEMENTAL INDENTURE
SUBSIDIARY GUARANTEES

THIRD SUPPLEMENTAL INDENTURE (this “Supplemental Indenture”), dated as of April 2, 2015, among the Subsidiary Guarantors listed on Schedule I hereto (the “Guaranteeing Subsidiaries”), each a wholly-owned domestic subsidiary of Dynegy Inc. (or its permitted successor), a Delaware corporation (the “Company”), the Company, the other Subsidiary Guarantors (as defined in the Indenture referred to herein) and Wilmington Trust, National Association, as trustee under the indentures referred to below (the “Trustee”).

W I T N E S S E T H

WHEREAS, the Company (as successor by merger to Dynegy Finance II, Inc.) has heretofore executed and delivered to the Trustee an indenture (as supplemented, the “Indenture”), dated as of October 27, 2014, between the Company and the Trustee, providing for the original issuance of an aggregate principal amount of $1,050,000,000 of 7.375% Senior Notes due 2022 (the “Initial Notes”) and, subject to the terms of the Indenture, future unlimited issuances of 7.375% Senior Notes due 2022 (the “Additional Notes, and together with the Initial Notes, the “Notes”);

WHEREAS, the Indenture provides that under certain circumstances the Guaranteeing Subsidiaries shall execute and deliver to the Trustee a supplemental indenture pursuant to which the Guaranteeing Subsidiaries shall unconditionally guarantee all of the Company’s Obligations under the Notes and the Indenture (the “Subsidiary Guarantees”); and

WHEREAS, pursuant to Section 4.07 of the Indenture, the Trustee, the Company and the other Subsidiary Guarantors are authorized and required to execute and deliver this Supplemental Indenture.

NOW THEREFORE, in consideration of the foregoing and for good and valuable consideration, the receipt of which is hereby acknowledged, the Guaranteeing Subsidiaries, the Trustee, the Company and the other Subsidiary Guarantors mutually covenant and agree for the equal and ratable benefit of the Holders of the Notes as follows:

1. Capitalized Terms. Unless otherwise defined in this Supplemental Indenture, capitalized terms used herein without definition shall have the meanings assigned to them in the Indenture.

2. Agreement to be Bound; Guarantee. Each of the Guaranteeing Subsidiaries hereby become a party to the Indenture as a Subsidiary Guarantor and as such will have all of the rights and be subject to all of the Obligations and agreements of a Subsidiary Guarantor under the Indenture. Each of the Guaranteeing Subsidiaries hereby agree to be bound by all of the provisions of the Indenture applicable to a Subsidiary Guarantor and to perform all of the Obligations and agreements of a Subsidiary Guarantor under the Indenture. In furtherance of the foregoing, each of the Guaranteeing Subsidiaries shall be deemed a Subsidiary Guarantor for purposes of Article 10 of the Indenture, including, without limitation, Section 10.02 thereof.

3. NEW YORK LAW TO GOVERN. THE INDENTURE, THE NOTES, THIS SUPPLEMENTAL INDENTURE AND THE SUBSIDIARY GUARANTEES SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK.

4. Counterparts. The parties may sign any number of copies of this Supplemental Indenture. Each signed copy shall be an original, but all of them together represent the same agreement.

5. Effect of Headings. The Section headings herein are for convenience only and shall not affect the construction hereof.

6. The Trustee. The Trustee shall not be responsible in any manner whatsoever for or in respect of the validity or sufficiency of this Supplemental Indenture or for or in respect of the recitals contained herein, all of which recitals are made solely by the Guaranteeing Subsidiaries and the Company.

7. Ratification of Indenture; Supplemental Indenture Part of Indenture. Except as expressly amended hereby, the Indenture is in all respects ratified and confirmed and all the terms, conditions and provisions

thereof shall remain in full force and effect. This Supplemental Indenture shall form a part of the Indenture for all purposes, and every Holder of Notes heretofore or hereafter authenticated and delivered shall be bound hereby.

[Signature Page Follows]

IN WITNESS WHEREOF, we have hereunto signed our names as of the date set forth below.

Dated:	April 2, 2015

		DYNEGY INC.

		By:		/s/ Robert C. Flexon
		Name:		Robert C. Flexon
		Title:		President & Chief Executive Officer


		DYNEGY ENERGY SERVICES (EAST), LLC

		By:	/s/ Robert C. Flexon
		Name:	Robert C. Flexon
		Title:	Chief Executive Officer

		DYNEGY RESOURCE I, LLC
		DYNEGY COMMERCIAL ASSET MANAGEMENT, LLC DYNEGY CONESVILLE, LLC
		DYNEGY DICKS CREEK, LLC DYNEGY FAYETTE II, LLC DYNEGY HANGING ROCK II, LLC DYNEGY KILLEN, LLC
		DYNEGY LEE II, LLC
		DYNEGY MIAMI FORT, LLC DYNEGY STUART, LLC DYNEGY WASHINGTON II, LLC DYNEGY ZIMMER, LLC
		DYNEGY COAL GENERATION, LLC DYNEGY GAS GENERATION, LLC DYNEGY GENERATION HOLDCO, LLC

		By:	/s/ Robert C. Flexon
		Name:	Robert C. Flexon
		Title:	President & Chief Executive Officer

[SIGNATURE PAGES CONTINUE]

	SUBSIDIARY GUARANTORS:

	DYNEGY ENERGY SERVICES, LLC

	By:	/s/ Robert C. Flexon
	Name:	Robert C. Flexon
	Title:	Chief Executive Officer

	BLUE RIDGE GENERATION LLC
	BLACK MOUNTAIN COGEN, INC.
	CASCO BAY ENERGY COMPANY, LLC
	DYNEGY ADMINISTRATIVE SERVICES COMPANY
	DYNEGY COAL HOLDCO, LLC
	DYNEGY COAL INVESTMENTS HOLDINGS, LLC
	DYNEGY COAL TRADING & TRANSPORTATION, L.L.C.
	DYNEGY EQUIPMENT, LLC
	DYNEGY GASCO HOLDINGS, LLC
	DYNEGY GAS HOLDCO, LLC
	DYNEGY GAS IMPORTS, LLC
	DYNEGY GAS INVESTMENTS, LLC
	DYNEGY GAS INVESTMENTS HOLDINGS, LLC DYNEGY GLOBAL LIQUIDS, INC.
	DYNEGY KENDALL ENERGY, LLC
	DYNEGY MARKETING AND TRADE, LLC
	DYNEGY MIDWEST GENERATION, LLC
	DYNEGY MORRO BAY, LLC
	DYNEGY MOSS LANDING, LLC DYNEGY OAKLAND, LLC
	DYNEGY OPERATING COMPANY
	DYNEGY POWER, LLC
	DYNEGY POWER GENERATION INC.
	DYNEGY POWER MARKETING, LLC
	DYNEGY SOUTH BAY, LLC
	HAVANA DOCK ENTERPRISES, LLC ILLINOVA CORPORATION
	ONTELAUNEE POWER OPERATING COMPANY, LLC SITHE ENERGIES, INC.
	SITHE/INDEPENDENCE LLC

	By:	/s/ Robert C. Flexon
	Name:	Robert C. Flexon
	Title:	President & Chief Executive Officer

[SIGNATURE PAGES CONTINUE]

	EQUIPOWER RESOURCES CORP.
	DYNEGY RESOURCE II, LLC
	DYNEGY RESOURCE III, LLC
	DYNEGY RESOURCES HOLDCO I, LLC
	DYNEGY RESOURCES HOLDCO II, LLC
	DYNEGY RESOURCES GENERATING HOLDCO, LLC
	RICHLAND GENERATION EXPANSION LLC
	MILFORD POWER COMPANY, LLC
	LAKE ROAD HOLDINGS GP, LLC
	LAKE ROAD HOLDINGS LP, LLC
	LAKE ROAD GENERATING COMPANY, L.P.
	RSG POWER, LLC
	RICHLAND-STRYKER GENERATION, LLC
	DYNEGY RESOURCES MANAGEMENT, LLC
	DIGHTON POWER, LLC
	MASSPOWER HOLDCO, LLC
	MASSPOWER PARTNERS I, LLC
	MASSPOWER PARTNERS II, LLC
	MASSPOWER
	LIBERTY ELECTRIC GENERATION HOLDINGS, LLC
	LEP HOLDINGS, LLC
	LIBERTY ELECTRIC PA 2, LLC
	LIBERTY ELECTRIC POWER, LLC
	TOMCAT POWER, LLC
	KINCAID HOLDINGS, LLC
	KINCAID GENERATION, L.L.C.
	KINCAID ENERGY SERVICES COMPANY, LLC
	ELWOOD EXPANSION HOLDINGS, LLC
	ELWOOD ENERGY HOLDINGS, LLC
	ELWOOD ENERGY LLC
	ELWOOD SERVICES COMPANY, LLC
	ELWOOD ENERGY HOLDINGS II, LLC
	BRAYTON POINT HOLDINGS, LLC
	ECP II-B (BRAYTON POINT IP) CORP
	ECP II-C (BRAYTON POINT IP) CORP

	By:	/s/ Robert C. Flexon
	Name:	Robert C. Flexon
	Title:	President & Chief Executive Officer

[SIGNATURE PAGES CONTINUE]

	WILMINGTON TRUST, NATIONAL ASSOCIATION,
	as Trustee

	By:	/s/ Boris Treyger
	Name:	Boris Treyger
	Title:	Vice President

SCHEDULE I

SUBSIDIARY GUARANTORS

DYNEGY ENERGY SERVICES (EAST), LLC

DYNEGY RESOURCE I, LLC

DYNEGY COMMERCIAL ASSET MANAGEMENT, LLC

DYNEGY CONESVILLE, LLC

DYNEGY DICKS CREEK, LLC

DYNEGY FAYETTE II, LLC

DYNEGY HANGING ROCK II, LLC

DYNEGY KILLEN, LLC

DYNEGY LEE II, LLC

DYNEGY MIAMI FORT, LLC

DYNEGY STUART, LLC

DYNEGY WASHINGTON II, LLC

DYNEGY ZIMMER, LLC

DYNEGY COAL GENERATION, LLC

DYNEGY GAS GENERATION, LLC

DYNEGY GENERATION HOLDCO, LLC