CONTINGENT CONTRIBUTION AGREEMENT

Exhibit 10.2

Execution Copy

CONTINGENT CONTRIBUTION AGREEMENT

Dated as of May 1, 2009

By and among

NRG ENERGY, INC.

NRG RETAIL, LLC

RERH HOLDINGS, LLC

RELIANT ENERGY RETAIL HOLDINGS, LLC

and

MERRILL LYNCH COMMODITIES, INC.

TABLE OF CONTENTS

CONTINGENT CONTRIBUTION AGREEMENT

THIS CONTINGENT CONTRIBUTION AGREEMENT, dated as of May 1, 2009 (this “ Agreement ”), is entered into by and among NRG ENERGY, INC., a Delaware corporation (“ Parent ”), NRG RETAIL, LLC, a Delaware limited liability company (“ NRG Retail ”), RERH HOLDINGS, LLC, a Delaware limited liability company (“ RERH Holdings ”), RELIANT ENERGY RETAIL HOLDINGS, LLC, a Delaware limited liability company (“ RERH ”) and Merrill Lynch Commodities, Inc., a Delaware corporation (“ MLCI ”). Capitalized terms used herein but not defined herein shall have the respective meanings assigned to such terms in the CSRA (as defined below), provided that, if, within such definition in the CSRA a further term is used which is defined herein, then such further term shall have the meaning given to such further term herein.

W I T N E S S E T H :

          WHEREAS, MLCI is entering into an Amended and Restated Credit Sleeve and Reimbursement Agreement (the “ CSRA ”) dated as of May 1, 2009 with RERH Holdings, the Other Reliant Retail Obligors and Merrill Lynch & Co., Inc. concurrently with the entering into of this Agreement;

          WHEREAS, NRG Retail has entered into a LLC Membership Interest Purchase Agreement dated as of May 1, 2009 with Reliant Energy, Inc. (“ REI ”), a Delaware corporation (the “ Purchase and Sale Agreement ”), pursuant to which NRG Retail has agreed to purchase, and REI has agreed to sell to NRG Retail, 100% of the equity interest in RERH Holdings, Reliant Energy Retail Services, LLC, a Delaware limited liability company, and Reliant Energy Services Texas, LLC, a Delaware limited liability company, owned by REI (the “ Retail Acquisition ”) concurrently with the entering into of this Agreement;

          WHEREAS, in order to induce the parties to the CSRA to enter into the CRSA pursuant to the terms and subject to the conditions set forth herein and in the CSRA, Parent desires to make at the times specified herein and on the terms set forth herein capital contributions to RERH.

          NOW, THEREFORE, in consideration of the premises and the mutual agreements hereinafter contained, and for other good and valuable consideration, the receipt of which is hereby acknowledged, RERH Holdings, Parent, NRG Retail, RERH and MLCI, intending to be legally bound, hereby agree as follows:

ARTICLE I

DEFINITIONS

SECTION 1.1 General . The definitions of terms herein shall apply equally to the singular and plural forms of the terms defined. Whenever the context may require, any pronoun shall include the corresponding masculine, feminine and neuter forms. The words “include”, “includes” and “including” shall be deemed to be followed by the phrase “without limitation”. The word “will” shall be construed to have the same meaning and effect as the word “shall”. Unless the context requires otherwise (a) any definition of or reference to any agreement, instrument or other document herein shall be construed as referring to such agreement, instrument or other document as from time to time amended, restated, supplemented or otherwise modified, renewed or replaced (subject to any restrictions on such

amendments, restatements, supplements or modifications, renewals or replacements set forth therein or herein), (b) any reference herein to any Person shall be construed to include such Person’s successors and permitted assigns, (c) the words “herein”, “hereof” and “hereunder”, and words of similar import, shall be construed to refer to this Agreement in its entirety and not to any particular provision hereof and (d) all references herein to Sections, Exhibits and Schedules shall be construed to refer to Sections of, and Exhibits and Schedules to, this Agreement.

SECTION 1.2 Specific Terms . Whenever used in this Agreement, the following words and phrases, unless the context otherwise requires, shall have the following meanings:

          “ Business Day ” means any day other than a Saturday, Sunday or other day on which commercial banks are authorized to close under the Laws of, or are in fact closed in, Houston, Texas or New York City.

          “ Contractual Obligation ” means, as to any Person, any provision of any security issued by such Person or of any agreement, instrument or other undertaking to which such Person is a party or by which it or any of its property is bound.

          “ Core Collateral Subsidiary ” shall mean each of Louisiana Generating LLC, Huntley Power LLC, Dunkirk Power LLC, Indian River Power LLC, Oswego Harbor Power LLC, Astoria Gas Turbine LLC, Arthur Kill Power LLC, NRG Texas LP, NRG South Texas LP and NRG Power Marketing.

          “ ERCOT ” means the Electric Reliability Council of Texas, or any successor thereto.

          “ Excluded Subsidiaries ” means collectively, the “Excluded Subsidiaries” from time to time as defined in the NRG Credit Agreement and the “Immaterial Subsidiaries” from time to time as defined in the Senior Note Documents.

          “ Exempt Subsidiaries ” shall mean, collectively, NRG Ilion LP LLC, NRG Ilion Limited Partnership, Meriden Gas Turbine LLC, LSP-Nelson Energy LLC, NRG Nelson Turbines LLC, NRG Jackson Valley Energy I, Inc., NRG McClain LLC, NRG Audrain Holding LLC, NRG Audrain Generating LLC, NRG Peaker Finance Company LLC, Bayou Cove Peaking Power, LLC, Big Cajun I Peaking Power LLC, NRG Rockford LLC, NRG Rockford II LLC, NRG Rockford Equipment II LLC, NRG Sterlington Power LLC and NRG Rockford Acquisition LLC, and shall not, in any event, include any Core Collateral Subsidiary.

          “ Governmental Authority ” means the government of the United States of America, any other nation or any political subdivision thereof, whether state, county, or local, and any agency, authority, instrumentality, regulatory body, court, central bank, independent system operator, transmission organization or other entity to the extent exercising executive, legislative, judicial, taxing, monetary, regulatory, supervisory or administrative powers or functions of or pertaining to government.

          “ Laws ” means, collectively, all international, foreign, federal, state and local statutes, treaties, rules, guidelines, regulations, ordinances, codes and administrative or judicial precedents or authorities, including the interpretation or administration thereof by any Governmental Authority charged with the enforcement, interpretation or administration thereof, and all applicable administrative orders, directed duties, requests, licenses, authorizations and permits of any Governmental Authority.

          “ Material Adverse Effect ” means, with respect to any Person, a material adverse effect upon (i) the business, operations, property or financial condition of such Person and its Subsidiaries taken

as a whole, or (ii) the validity or enforceability against any such Person or any of its Subsidiaries of this Agreement or any other Transaction Document to which it is a party or the transactions contemplated thereby or the rights and remedies of MLCI thereunder or the performance by such Person of its obligations thereunder.

          “ NRG Credit Agreement ” means the Second Amended and Restated Credit and Guaranty Agreement dated as of June 8, 2007 among Parent, the lenders referred to therein, and Citicorp North America, as administrative agent and collateral agent, as each of the foregoing has been amended, restated, supplemented or otherwise modified from time to time but shall not include any restatement, replacement or refinancing thereof unless the principal amount of Indebtedness outstanding and/or available to be drawn under such replacement or refinancing is at least $100 million.

          “ NRG Parent Debt ” means (a) Senior Notes and (b) NRG Credit Agreement.

          “ Organizational Documents ” means, (a) with respect to any corporation, the certificate or articles of incorporation and the bylaws (or equivalent or comparable constitutive documents with respect to any non-U.S. jurisdiction); (b) with respect to any limited liability company, the certificate or articles of formation or organization and operating agreement; and (c) with respect to any partnership, joint venture, trust or other form of business entity, the partnership, joint venture or other applicable agreement of formation or organization and any agreement, instrument, filing or notice with respect thereto filed in connection with its formation or organization with the applicable Governmental Authority in the jurisdiction of its formation or organization and, if applicable, any certificate or articles of formation or organization of such entity.

          “ Person ” means any individual, corporation, firm, partnership, joint venture, association, joint-stock company, trust, unincorporated organization, limited liability company or government or other entity.

          “ Significant Subsidiary ” shall mean any Subsidiary that would be a “significant subsidiary” as defined in Article 1, Rule 1-02 of Regulation S-X, promulgated pursuant to the Securities Act, as such Regulation is in effect on the date hereof and shall in any event include the Core Collateral Subsidiaries.

          “ Solvent ” mean, with respect to any Person on any date of determination, that on such date (i) the fair value of the property of such Person is greater than the total amount of liabilities, including contingent liabilities, of such Person, (ii) the present fair salable value of the assets of such Person is not less than the amount that will be required to pay the probable liability of such Person on its debts as they become absolute and matured, (iii) such Person does not intend to, and does not believe that it will, incur debts or liabilities beyond such Person’s ability to pay such debts and liabilities as they mature and (iv) such Person is not engaged in business or a transaction, and is not about to engage in business or a transaction, for which such Person’s property would constitute an unreasonably small capital. The amount of contingent liabilities at any time shall be computed as the amount that, in the light of all the facts and circumstances existing at such time, represents the amount that can reasonably be expected to become an actual or matured liability; provided , that if the context in which “Solvent” is used refers to a Person together with its Subsidiaries, Person as used in this definition shall be deemed to be a reference to such Person together with its Subsidiaries.

          “ Subsidiary ” of a Person means a corporation, partnership, joint venture, limited liability company or other business entity of which a majority of the shares of securities or other interests having ordinary voting power for the election of directors or other governing body (other than securities or

interests having such power only by reason of the happening of a contingency) are at the time beneficially owned, or the management of which is otherwise controlled, directly, or indirectly through one or more intermediaries, or both, by such Person.

          “ Unrestricted Subsidiary ” shall have the meaning set forth in the NRG Credit Agreement.

ARTICLE II

CONTRIBUTIONS

SECTION 2.1 Initial Contribution . Contemporaneously with the closing of the Retail Acquisition, on the date hereof, Parent shall contribute an amount in cash equal to $200,000,000 to the capital of RERH Holdings (the “ Initial Contribution ”), without recourse, to fund the working capital needs of RERH Holdings and its Subsidiaries in accordance with Section 6.11(c) of the CSRA, and RERH Holdings hereby agrees to accept the Initial Contribution. Parent hereby acknowledges that the Initial Contribution to RERH Holdings hereunder is absolute and irrevocable, without reservation or retention of any interest whatsoever by Parent. RERH hereby irrevocably directs Parent to make the Initial Contribution directly as if it were “revenue” under Section 6.11 of the CSRA.

SECTION 2.2 Contingent Equity Contributions .

          (a) If, and only if, on November 1, 2009, the then outstanding Exposure under the CSRA exceeds the Target Exposure for such date (the “ Additional Contribution Trigger ”), Parent shall within two (2) Business Days of such date, make a capital contribution in cash to RERH equal to $250,000,000 (“ Additional Contribution ”). Parent hereby acknowledges that any Additional Contribution to RERH hereunder, subject to the occurrence of the Additional Contribution Trigger or an Accelerated Contribution Event, (i) is absolute and irrevocable, without recourse, without reservation or retention of any interest whatsoever by Parent and (ii) shall be required to be contributed by Parent regardless of whether the amount of such Additional Contribution would be sufficient to reduce Exposure under the CSRA to the amount required for such date in the ESDS. RERH hereby irrevocably directs Parent to make all Additional Contributions directly to the account of MLCI in accordance with Section 6.18 of the CSRA.

          (b) If, and only if, on October 31, 2010, either (i) the Exposure under the CSRA is in excess of zero or (ii) the Credit Sleeve Termination Date has not occurred (either of (i) or (ii), a “ Final Contribution Trigger ”), Parent shall on such date make a capital contribution in cash to RERH in an amount sufficient to permit RERH to reduce Exposure under the CSRA to zero on such date and to the extent necessary to cause the Credit Sleeve Termination Date to occur on such date (“ Final Contribution ” and together with any Additional Contribution, the “ Contingent Equity Contributions ”); provided , that Parent shall not be obligated to contribute an amount under this clause (b) in excess of $400 million (“ Maximum Amount of the Final Contribution ”). Parent hereby acknowledges that the Final Contribution to RERH hereunder, subject to the occurrence of the Final Contribution Trigger or an Accelerated Contribution Event (i) is absolute and irrevocable, without recourse, without reservation or retention of any interest whatsoever by Parent and (ii) shall be required to be contributed by Parent regardless of whether the amount of such Final Contribution would be sufficient to reduce Exposure under the CSRA to zero or to cause the Credit Sleeve Termination Date to occur. RERH hereby irrevocably directs Parent to make the Final Contribution directly to the account of MLCI in accordance with Section 6.18 of the CSRA.

          (c) To the extent required by law or otherwise, the Parent, NRG Retail, RERH Holdings and RERH agree that, notwithstanding that Parent shall make Contingent Equity Contributions directly to RERH all Contingent Equity Contributions shall be deemed to have been made by the Parent to NRG Retail with a subsequent contribution from NRG Retail to RERH Holdings with a subsequent contribution from RERH Holdings to RERH. Each of NRG Retail and RERH Holdings hereby acknowledges that it shall not have any interest in or right to any Contingent Equity Contribution and to the extent it shall be deemed to have any such interest or right therein it hereby absolutely and irrevocably assigns all of its rights, title and interest hereunder (including to any Contingent Equity Contributions hereunder), without recourse, without reservation or retention of any interest whatsoever to RERH.

          (d) It is the intention of Parent, NRG Retail, RERH Holdings and RERH that the Contingent Equity Contribution amounts contributed by Parent to the capital of RERH pursuant to this Agreement shall not be part of Parent’s, NRG Retail’s or RERH Holdings’ estate in the event of the filing of a bankruptcy petition by or against Parent, NRG Retail or RERH Holdings under any bankruptcy or similar law.

          (e) The Parent, NRG Retail, RERH Holdings and RERH agree that the obligations of the Parent are not conditioned on RERH, NRG Retail or RERH Holdings issuing any securities to the Parent, NRG Retail or RERH Holdings in respect of any payment made in respect of the Parent’s obligations pursuant to Sections 2.1 and 2.2 hereof and the obligations of the Parent shall not be construed as an obligation of the Parent, NRG Retail or RERH Holdings to extend a loan, credit or financial accommodation to NRG Retail, RERH Holdings or RERH.

SECTION 2.3 Accelerated Contribution Events . Notwithstanding the forgoing Sections 2.1 and 2.2, if, and only if:

     (a) an involuntary proceeding shall be commenced or an involuntary petition shall be filed seeking (i) liquidation, reorganization or other relief in respect of the Parent, any of its Significant Subsidiaries (other than the Exempt Subsidiaries, the Unrestricted Subsidiaries and the Excluded Subsidiaries) or any group of Significant Subsidiaries (other than the Exempt Subsidiaries, the Unrestricted Subsidiaries and the Excluded Subsidiaries) that, taken together, would const