FORTY-FIFTH SUPPLEMENTAL INDENTURE FOR ADDITIONAL SUBSIDIARY GUARANTEES

EXHIBIT 4.1

FORTY-FIFTH SUPPLEMENTAL INDENTURE FOR
ADDITIONAL SUBSIDIARY GUARANTEES

FORTY-FIFTH SUPPLEMENTAL INDENTURE (this “Supplemental Indenture for Additional Guarantees”), dated as of May 20, 2011, among Energy Protection Insurance Company, Meriden Gas Turbines LLC, NRG Development Company Inc., NRG Energy Labor Services LLC, NRG Energy Services Group LLC, NRG Ilion Limited Partnership, NRG Ilion LP LLC, NRG Maintenance Services LLC, NRG Mextrans Inc., NRG PacGen Inc., NRG Rockford Acquisition LLC, NRG Services Corporation, NRG SimplySmart Solutions LLC, O’Brien Cogeneration, Inc. II, ONSITE Energy, Inc. and Reliant Energy Northeast LLC (each a “Guaranteeing Subsidiary” and together the “Guaranteeing Subsidiaries”), each an indirect subsidiary of NRG Energy, Inc., a Delaware corporation (the “Company”), the Company, the Existing Guarantors set forth on the signature page hereto (the “Existing Guarantors”) and Law Debenture Trust Company of New York, as trustee under the indentures referred to below (the “Trustee”).

W I T N E S S E T H

WHEREAS, the Company has heretofore executed and delivered to the Trustee an indenture (the “Base Indenture”), dated as of February 2, 2006, between the Company and the Trustee, as amended by a second supplemental indenture (the “Second Supplemental Indenture”), dated as of February 2, 2006, among the Company, the Guarantors named therein and the Trustee, providing for the original issuance of an aggregate principal amount of $2,400 million of 7.375% Senior Notes due 2016 (the “Initial Notes”), and, subject to the terms of the Indenture, future unlimited issuances of 7.375% Senior Notes due 2016 (the “Additional Notes,” and together with the Initial Notes, the “Notes”), a fourth supplemental indenture, dated as of March 14, 2006, among the Company, the Existing Guarantors party thereto and the Trustee (the “Fourth Supplemental Indenture”), a sixth supplemental indenture, dated as of April 28, 2006, among the Company, the Existing Guarantors party thereto and the Trustee (the “Sixth Supplemental Indenture”), an eighth supplemental indenture, dated as of November 13, 2006, among the Company, the Existing Guarantors party thereto and the Trustee (the “Eight Supplemental Indenture”), an eleventh supplemental indenture, dated as of July 19, 2007, among the Company, the Existing Guarantors party thereto and the Trustee (the “Eleventh Supplemental Indenture”), a fourteenth supplemental indenture, dated as of August 28, 2007, among the Company, the Existing Guarantors party thereto and the Trustee (the “Fourteenth Supplemental Indenture”), a seventeenth supplemental indenture, dated as of April 28, 2009 among the Company, the Existing Guarantors party thereto and the Trustee (the “Seventeenth Supplemental Indenture”), a twentieth supplemental indenture, dated as of May 8, 2009 among the Company, the Existing Guarantors party thereto and the Trustee (the “Twentieth Supplemental Indenture”) and a twenty-fifth supplemental indenture, dated as of October 5, 2009 among the Company, the Existing Guarantors party thereto and the Trustee (the “Twenty-Fifth Supplemental Indenture”), a twenty-ninth supplemental indenture, dated as of April 16, 2010, among the Company, the Existing Guarantors party thereto and the Trustee (the “Twenty-Ninth Supplemental Indenture”), a thirty-third supplemental indenture, dated as of June 23, 2010, among the Company, the Existing Guarantors party thereto and the Trustee (the “Thirty-Third Supplemental Indenture”) and a thirty-eighth supplemental indenture, dated as of December 15, 2010, among the Company, the Existing Guarantors party thereto and the Trustee (the “Thirty-Eighth Supplemental Indenture”) and a forty-fourth supplemental indenture, dated as of May 9, 2011, among the Company, the Existing Guarantors and the Trustee (the “Forty-Fourth Supplemental Indenture” and together with the Base Indenture, the Second Supplemental Indenture, the Fourth Supplemental Indenture, the Sixth Supplemental Indenture, the Eighth Supplemental Indenture, the Eleventh Supplemental Indenture, the Fourteenth Supplemental Indenture, the Seventeenth Supplemental Indenture, the Twentieth Supplemental Indenture, the Twenty-Fifth Supplemental Indenture, the Twenty-Ninth Supplemental Indenture, the Thirty-Third Supplemental Indenture and the Thirty-Eighth Supplemental Indenture, the “Indenture”);

1

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 “Additional Guarantees”); and

WHEREAS, pursuant to Section 4.17 of the Second Supplemental Indenture, the Trustee, the Company and the Existing Guarantors are authorized and required to execute and deliver this Supplemental Indenture for Additional Guarantees.

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 Existing 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 for Additional Guarantees, capitalized terms used herein without definition shall have the meanings assigned to them in the Indenture.

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

3.                                       NEW YORK LAW TO GOVERN.  THE INTERNAL LAW OF THE STATE OF NEW YORK SHALL GOVERN AND BE USED TO CONSTRUE THIS SUPPLEMENTAL INDENTURE FOR ADDITIONAL GUARANTEES BUT WITHOUT GIVING EFFECT TO APPLICABLE PRINCIPLES OF CONFLICTS OF LAW TO THE EXTENT THAT THE APPLICATION OF THE LAWS OF ANOTHER JURISDICTION WOULD BE REQUIRED THEREBY.

4.                                       Counterparts. The parties may sign any number of copies of this Supplemental Indenture for Additional Guarantees.  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 for Additional Guarantees 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 for Additional Guarantees 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 for Additional Guarantees shall form a part of the Indenture for all purposes, and every Holder of Notes heretofore or hereafter authenticated and delivered shall by bound hereby.

2

IN WITNESS WHEREOF, the parties hereto have caused this Supplemental Indenture for Additional Guarantees to be duly executed and attested, all as of the date first above written.

Signature Page to Forty-Fifth Supplemental Indenture

Signature Page to Forty-Fifth Supplemental Indenture

Signature Page to Forty-Fifth Supplemental Indenture

Signature Page to Forty-Fifth Supplemental Indenture

Signature Page to Forty-Fifth Supplemental Indenture

Signature Page to Forty-Fifth Supplemental Indenture

Signature Page to Forty-Fifth Supplemental Indenture

Signature Page to Forty-Fifth Supplemental Indenture