UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 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): December 15, 2010

NRG ENERGY, INC.

(Exact name of Registrant as specified in its charter)

211 Carnegie Center, Princeton, New Jersey 08540
(Address of principal executive offices, including zip code)

(609) 524-4500
(Registrant’s telephone number, including area code)

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

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

o            Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

o            Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

o            Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

o            Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Item 1.01 Entry Into a Material Definitive Agreements.

On December 15, 2010, NRG Energy, Inc. (“NRG”), the subsidiaries of NRG named in the Thirty-Second Supplemental Indenture (as hereinafter defined) (the “Existing Guarantors”), Cottonwood Development LLC, Cottonwood Generating Partners II LLC, Cottonwood Generating Partners I LLC, Cottonwood Generating Partners III LLC, Cottonwood Energy Company LP, Cottonwood Technology Partners LP and Green Mountain Energy Company (the “Guaranteeing Subsidiaries”) and Law Debenture Trust Company of New York, as trustee (the “Trustee”), entered into a thirty-seventh supplemental indenture (the “Thirty-Seventh Supplemental Indenture”), supplementing the indenture, dated as of February 2, 2006 (the “Base Indenture”), among NRG and the Trustee, as supplemented by a first supplemental indenture, dated as of February 2, 2006, among NRG, the guarantors named therein and the Trustee, pursuant to which NRG issued $1,200,000,000 aggregate principal amount of 7.250% senior notes due 2014 (the “2014 Notes”), and as supplemented by a third supplemental indenture, dated as of March 14, 2006, among NRG, the Existing Guarantors party thereto and the Trustee, a fifth supplemental indenture, dated as of April 28, 2006, among NRG, the Existing Guarantors party thereto and the Trustee, a seventh supplemental indenture, dated as of November 13, 2006 among NRG, the Existing Guarantors party thereto and the Trustee, a tenth supplemental indenture, dated as of July 19, 2007 among NRG, the Existing Guarantors party thereto and the Trustee, a thirteenth supplemental indenture, dated as of August 28, 2007, among NRG, the Existing Guarantors party thereto and the Trustee, a sixteenth supplemental indenture, dated as of April 28, 2009, among NRG, the Existing Guarantors party thereto and the Trustee, a nineteenth supplemen tal indenture, dated as of May 8, 2009, among NRG, the Existing Guarantors party thereto and the Trustee, a twenty-fourth supplemental indenture, dated as of October 5, 2009, among NRG, the Existing Guarantors party thereto and the Trustee and a twenty-eighth supplemental indenture, dated as of April 16, 2010, among NRG, the Existing Guarantors party thereto and the Trustee and a thirty-second supplemental indenture, dated as of June 23, 2010 (the “Thirty-Second Supplemental Indenture”), among NRG, the Existing Guarantors and the Trustee. Pursuant to the Thirty-Seventh Supplemental Indenture, the Guaranteeing Subsidiaries became guarantors of NRG’s obligations under its 2014 Notes.

On December 15, 2010, NRG, the Existing Guarantors, the Guaranteeing Subsidiaries and the Trustee entered into a thirty-eighth supplemental indenture (the “Thirty-Eighth Supplemental Indenture”), supplementing the Base Indenture, as supplemented by a second supplemental indenture, dated as of February 2, 2006, among NRG, the guarantors named therein and the Trustee, pursuant to which NRG issued $2,400,000,000 aggregate principal amount of 7.375% senior notes due 2016 (the “2016 Notes”), and as supplemented by a fourth supplemental indenture, dated as of March 14, 2006, among NRG, the Existing Guarantors party thereto and the Trustee, a sixth supplemental indenture, dated as of April 28, 2006, among NRG, the Existing Guarantors party thereto and the Trustee an eighth supplemental indenture, dated as of November 13, 2006, among NRG, the Existing Guara ntors party thereto and the Trustee, an eleventh supplemental indenture, dated as of July 19, 2007, among NRG, the Existing Guarantors party thereto and the Trustee, a fourteenth supplemental indenture, dated as of August 28, 2007, among NRG, the Existing Guarantors party thereto and the Trustee , a seventeenth supplemental indenture, dated as of April 28, 2009, among NRG, the Existing Guarantors party thereto and the Trustee, a twentieth supplemental indenture, dated as of May 8, 2009, among NRG, the Existing Guarantors party thereto and the Trustee, a twenty-fifth supplemental indenture, dated as of October 5, 2009, among NRG, the Existing Guarantors party thereto and the Trustee, a twenty-ninth supplemental indenture, dated as of April 16, 2010, among NRG, the Existing Guarantors party thereto and the Trustee and a thirty-third supplemental indenture, dated as of June 23, 2010, among NRG, the Existing Guarantors and the Trustee. Pursuant to the Thirty-Eighth Supplemental Indenture, the Guaranteeing Subsidiaries became guarantors of NRG’s obligations under its 2016 Notes.

On December 15, 2010, NRG, the Existing Guarantors, the Guaranteeing Subsidiaries and the Trustee entered into a thirty-ninth supplemental indenture (the “Thirty-Ninth Supplemental Indenture”), supplementing the Base Indenture, as supplemented by a ninth supplemental indenture, dated as of November 21, 2006, among NRG, the Existing Guarantors party thereto and the Trustee, pursuant to which NRG issued $1,100,000,000 aggregate principal amount of 7.375% senior notes due 2017 (the “2017 Notes”), and as supplemented by a twelfth supplemental indenture, dated as of July 19, 2007, among NRG, the Existing Guarantors party thereto and the Trustee, a fifteenth supplemental indenture, dated as of August 28, 2007, among NRG the Existing Guarantors party thereto and the Trustee, an eighteenth supplemental indenture, dated as of April 28, 2009, among NRG, the E xisting Guarantors party thereto and the Trustee, a twenty-first supplemental indenture, dated as of May 8, 2009, among NRG, the Existing Guarantors party thereto and the Trustee, a twenty-sixth supplemental indenture, dated as of October 5, 2009, among NRG, the Existing Guarantors party thereto and the Trustee, a thirtieth supplemental

indenture, dated as of April 16, 2010, among NRG, the Existing Guarantors party thereto and the Trustee and a thirty-fourth supplemental indenture, dated as of June 23, 2010, among NRG, the Existing Guarantors and the Trustee.  Pursuant to the Thirty-Ninth Supplemental Indenture, the Guaranteeing Subsidiaries became guarantors of NRG’s obligations under its 2017 Notes.

On December 15, 2010, NRG, the Existing Guarantors, the Guaranteeing Subsidiaries and the Trustee entered into the fortieth supplemental indenture (the “Fortieth Supplemental Indenture”), supplementing the Base Indenture, as supplemented by a twenty-second supplemental indenture, dated as of June 5, 2009, among NRG, the Existing Guarantors party thereto and the Trustee pursuant to which NRG issued $700,000,000 aggregate principal amount of 8.50% senior notes due 2019 (the “2019 Notes”), and as supplemented by a twenty-third supplemental indenture, dated as of July 14, 2009, among NRG, the Existing Guarantors party thereto and the Trustee, a twenty-seventh supplemental indenture, dated as of October 5, 2009, among NRG, the Existing Guarantors party thereto and the Trustee, a thirty-first supplemental indenture, dated as of April 16, 2010, among NRG, the Existing Guarantors party thereto and the Trustee and a thirty-fifth supplemental indenture, dated as of June 23, 2010, among NRG, the Existing Guarantors and the Trustee.. Pursuant to the Thirty-Ninth Supplemental Indenture, the Guaranteeing Subsidiaries became guarantors of NRG’s obligations under its 2019 Notes.

On December 15, 2010, NRG, the Existing Guarantors, the Guaranteeing Subsidiaries and the Trustee entered into the forty-first supplemental indenture (the “Forth-First Supplemental Indenture”), supplementing the Base Indenture, as supplemented by a thirty-sixth supplemental indenture, dated as of August 20, 2010, among NRG, the Existing Guarantors and the Trustee pursuant to which NRG issued $1,100,000,000 aggregate principal amount of 8.25% senior notes due 2020 (the “2020 Notes”). Pursuant to the Forty-First Supplemental Indenture, the Guaranteeing Subsidiaries became guarantors of NRG’s obligations under its 2020 Notes.

A copy of the Thirty-Seventh Supplemental Indenture is attached as Exhibit 4.1 to this Current Report on Form 8-K and is incorporated by reference herein.  A copy of the Thirty-Eighth Supplemental Indenture is attached as Exhibit 4.2 to this Current Report on Form 8-K and is incorporated by reference herein.  A copy of the Thirty-Ninth Supplemental Indenture is attached as Exhibit 4.3 to this Current Report on Form 8-K and is incorporated by reference herein.  A copy of the Fortieth Supplemental Indenture is attached as Exhibit 4.4 to this Current Report on Form 8-K and is incorporated by reference herein.  A copy of the Forty-First Supplemental Indenture is attached as Exhibit 4.5 to this Current Report on Form 8-K and is incorporated by reference herein.  The description of the material terms of the Thirty-Seventh Sup plemental Indenture, Thirty-Eighth Supplemental Indenture, Thirty-Ninth Supplemental Indenture, Fortieth Supplemental Indenture and Forty-First Supplemental Indenture is qualified in its entirety by reference to such exhibits.

Item 9.01 Financial Statements and Exhibits

(d)           Exhibits

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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.

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EXHIBIT INDEX

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Exhibit 4.1

THIRTY-SEVENTH SUPPLEMENTAL INDENTURE FOR
ADDITIONAL SUBSIDIARY GUARANTEES

THIRTY-SEVENTH SUPPLEMENTAL INDENTURE (this “Supplemental Indenture for Additional Guarantees”), dated as of December 15, 2010, among Cottonwood Development LLC, Cottonwood Generating Partners II LLC, Cottonwood Generating Partners I LLC, Cottonwood Generating Partners III LLC, Cottonwood Energy Company LP, Cottonwood Technology Partners LP and Green Mountain Energy Company (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 first supplemental indenture (the “First 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 $1,200 million of 7.250% Senior Notes due 2014 (the “Initial Notes”), and, subject to the terms of the Indenture, future unlimited issuances of 7.250% Senior Notes due 2014 (the “Additional Notes,” and together with the Initial Notes, the “Notes”), a third supplemental indenture (the “Third Supplemental Indenture
48;), dated as of March 14, 2006, among the Company, the Existing Guarantors party thereto and the Trustee, a fifth supplemental indenture (the “Fifth Supplemental Indenture”), dated as of April 28, 2006, among the Company, the Existing Guarantors party thereto and the Trustee, a seventh supplemental indenture (the “Seventh Supplemental Indenture”), dated as of November 13, 2006, among the Company, the Existing Guarantors party thereto and the Trustee, a tenth supplemental indenture, dated as of July 19, 2007, among the Company, the Existing Guarantors party thereto and the Trustee (the “Tenth Supplemental Indenture”), a thirteenth supplemental indenture (the “Thirteenth Supplemental Indenture”), dated as of August 28, 2007, among the Company, the Existing Guarantors party thereto and the Trustee, a sixteenth supplemental indenture (the “Sixteenth Supplemental Indenture”), dated as of April 28, 2009, among the Company, the Guaranteeing Subsidiary, the Existing Guarantors party thereto and the Trustee, a nineteenth supplemental indenture, dated as of May 8, 2009, among the Company, the Existing Guarantors and the Trustee (the “Nineteenth Supplemental Indenture”), a twenty-fourth supplemental indenture, dated as of October 5, 2009, among the Company, the Existing Guarantors party thereto and the Trustee (the “Twenty-Fourth Supplemental Indenture”) and a twenty-eighth supplemental indenture, dated as of April 16, 2010, among the Company, the Existing Guarantors and the Trustee (the “Twenty-Eighth Supplemental Indenture”) and a thirty-second supplemental indenture, dated as of June 23, 2010, among the Company, the Existing Guarantors and the Trustee (the “Thirty-Second Supplemental Indenture” and together with the Base Indenture, the First Supplemental Indenture, the Third Supplemental Indenture, the Fifth Supplemen tal Indenture, the Seventh Supplemental Indenture, the Tenth Supplemental Indenture, the Thirteenth Supplemental Indenture, the Sixteenth Supplemental Indenture, the Nineteenth Supplemental Indenture, the Twenty-Fourth Supplemental Indenture and the Twenty-Eighth Supplemental Indenture, the “Indenture”);

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

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WHEREAS, pursuant to Section 4.17 of the First 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 First Supplemental 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 First Supplemental Indenture applicable to a Guarantor and to perform all of the Obligations and agreements of a Guarantor under the First Supplemental Indenture.  In furtherance of the foregoing, the Guaranteeing Subsidiaries shall be deemed Guarantors for purposes of Article 10 of the First 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.

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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 Thirty-Seventh Supplemental Indenture

Signature Page to Thirty-Seventh Supplemental Indenture

Signature Page to Thirty-Seventh Supplemental Indenture

Signature Page to Thirty-Seventh Supplemental Indenture

Signature Page to Thirty-Seventh Supplemental Indenture

Signature Page to Thirty-Seventh Supplemental Indenture

Exhibit 4.2

THIRTY-EIGHTH SUPPLEMENTAL INDENTURE FOR
ADDITIONAL SUBSIDIARY GUARANTEES

THIRTY-EIGHTH SUPPLEMENTAL INDENTURE (this “Supplemental Indenture for Additional Guarantees”), dated as of December 15, 2010, among Cottonwood Development LLC, Cottonwood Generating Partners II LLC, Cottonwood Generating Partners I LLC, Cottonwood Generating Partners III LLC, Cottonwood Energy Company LP, Cottonwood Technology Partners LP and Green Mountain Energy Company (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 Exis ting 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 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 “Seventeen th 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”) and a twenty-ninth supplemental indenture, dated as of April 16, 2010, among the Company, the Existing Guarantors and the Trustee (the “Twenty-Ninth Supplemental Indenture”) and a thirty-third supplemental indenture, dated as of June 23, 2010, among the Company, the Existing Guarantors and the Trustee (the “Thirty-Third 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 Supplementa l Indenture, the Fourteenth Supplemental Indenture, the Seventeenth Supplemental Indenture, the Twentieth Supplemental Indenture, the Twenty-Fifth Supplemental Indenture and the Twenty-Ninth Supplemental Indenture, the “Indenture”);

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

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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 Second Supplemental 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 Second Supplemental Indenture applicable to a Guarantor and to perform all of the Obligations and agreements of a Guarantor under the Second Supplemental 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.

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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 Thirty-Eighth Supplemental Indenture

Signature Page to Thirty-Eighth Supplemental Indenture

Signature Page to Thirty-Eighth Supplemental Indenture

Signature Page to Thirty-Eighth Supplemental Indenture

Signature Page to Thirty-Eighth Supplemental Indenture

Signature Page to Thirty-Eighth Supplemental Indenture

Exhibit 4.3

THIRTY-NINTH SUPPLEMENTAL INDENTURE FOR
ADDITIONAL SUBSIDIARY GUARANTEES

THIRTY-NINTH SUPPLEMENTAL INDENTURE (this “Supplemental Indenture for Additional Guarantees”), dated as of December 15, 2010, among Cottonwood Development LLC, Cottonwood Generating Partners II LLC, Cottonwood Generating Partners I LLC, Cottonwood Generating Partners III LLC, Cottonwood Energy Company LP, Cottonwood Technology Partners LP and Green Mountain Energy Company (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 ninth supplemental indenture (the “Ninth Supplemental Indenture”), dated as of November 21, 2006, among the Company, the Guarantors named therein and the Trustee, providing for the original issuance of an aggregate principal amount of $1,100 million of 7.375% Senior Notes due 2017 (the “Initial Notes”), and, subject to the terms of the Ninth Supplemental Indenture, future unlimited issuances of 7.375% Senior Notes due 2017 (the “Additional Notes,” and together with the Initial Notes, the “Notes”), as amended by a twelfth supplemental indenture, dated as of July 19, 2 007, among the Company, the Existing Guarantors party thereto and the Trustee (the “Twelfth Supplemental Indenture”), a fifteenth supplemental indenture, dated as of August 28, 2007, among the Company, the Existing Guarantors and the Trustee (the “Fifteenth Supplemental Indenture”), an eighteenth supplemental indenture dated as of April 28, 2009, among the Company, the Existing Guarantors party thereto and the Trustee (the “Eighteenth Supplemental Indenture”), a twenty-first supplemental indenture dated as of May 8, 2009, among the Company, the Existing Guarantors party thereto and the Trustee (the “Twenty-First Supplemental Indenture”), a twenty-sixth supplemental indenture dated as of October 5, 2009, among the Company, the Existing Guarantors party thereto and the Trustee (the “Twenty-Sixth Supplemental Indenture”) and a thirtieth supplemental indenture, dated as of April 16, 2010, among the Company, the Existing G uarantors and the Trustee (the “Thirtieth Supplemental Indenture”) and a thirty-fourth supplemental indenture, dated as of June 23, 2010, among the Company, the Existing Guarantors and the Trustee (the “Thirty-Fourth Supplemental Indenture” and together with the Base Indenture, the Ninth Supplemental Indenture, the Twelfth Supplemental Indenture, the Fifteenth Supplemental Indenture, the Eighteenth Supplemental Indenture, the Twenty-First Supplemental Indenture, the Twenty-Sixth Supplemental Indenture and the Thirtieth Supplemental Indenture, the “Indenture”);

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 Ninth 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:

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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 Ninth Supplemental Indenture as Guarantors and as such will have all of the rights and be subject to all of the Obligations and agreements of Guarantors under the Indenture.  The Guaranteeing Subsidiaries hereby agree to be bound by all of the provisions of the Ninth Supplemental Indenture applicable to a Guarantor and to perform all of the Obligations and agreements of a Guarantor under the Ninth Supplemental Indenture.  In furtherance of the foregoing, the Guaranteeing Subsidiaries shall be deemed Guarantors for purposes of Article 10 of the Ninth 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.

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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 Thirty-Ninth Supplemental Indenture

Signature Page to Thirty-Ninth Supplemental Indenture

Signature Page to Thirty-Ninth Supplemental Indenture

Signature Page to Thirty-Ninth Supplemental Indenture

Signature Page to Thirty-Ninth Supplemental Indenture

Signature Page to Thirty-Ninth Supplemental Indenture

Exhibit 4.4

FORTIETH SUPPLEMENTAL INDENTURE FOR
ADDITIONAL SUBSIDIARY GUARANTEES

FORTIETH SUPPLEMENTAL INDENTURE (this “Supplemental Indenture for Additional Guarantees”), dated as of December 15, 2010, among Cottonwood Development LLC, Cottonwood Generating Partners II LLC, Cottonwood Generating Partners I LLC, Cottonwood Generating Partners III LLC, Cottonwood Energy Company LP, Cottonwood Technology Partners LP and Green Mountain Energy Company (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 Twenty-Second Supplemental Indenture (the “Twenty-Second Supplemental Indenture”), dated as of June 5, 2009, among the Company, the Guarantors named therein and the Trustee, providing for the original issuance of an aggregate principal amount of $700 million of 8.50% Senior Notes due 2019 (the “Initial Notes”), and, subject to the terms of the Twenty-Second Supplemental Indenture, future unlimited issuances of 8.50% Senior Notes due 2019 (the “Additional Notes,” and together with the Initial Notes, the “Notes”), a twenty-third supplemental indenture, dated as of July 14, 2009, among the Company, the Existing Guarantors party thereto and the Trustee (the “Twenty-Third Supplemental Indenture”), a twenty-seventh supplemental indenture, dated as of October 5, 2009, among the Company, the Existing Guarantors party thereto and the Trustee (the “Twenty-Seventh Supplemental Indenture”) and a thirty-first supplemental indenture, dated as of April 16, 2010, among the Company, the Existing Guarantors and the Trustee (the “Thirty-First Supplemental Indenture”) and a thirty-fifth supplemental indenture, dated as of June 23, 2010, among the Company, the Existing Guarantors and the Trustee (the “Thirty-Fifth Supplemental Indenture” and together with the Base Indenture, the Twenty-Second Supplemental Indenture, the Twenty-Third Supplemental Indenture, the Twenty-Seventh Supplemental Indenture and the Thirty-First Supplemental Indenture, the “Indenture”);