1,016,684,029 20,855,057 Shares NRG Energy, Inc. COMMON STOCK UNDERWRITING AGREEMENT

Exhibit 1.01

$1,016,684,029
20,855,057 Shares

NRG Energy, Inc.

COMMON STOCK

UNDERWRITING AGREEMENT

January 25, 2006

To the Representatives of the Underwriters named in Schedule I hereto

Ladies and Gentlemen:

NRG Energy, Inc., a Delaware corporation (the “Company”), proposes to issue and sell to the underwriters named in Schedule I hereto (the “Underwriters”), for whom you are acting as representatives (the “Representatives”), 20,855,057 shares of its common stock, par value $0.01 per share (the “Firm Shares”). The Company also proposes to issue and sell to the Underwriters named in Schedule I not more than an additional 3,128,259 shares of its common stock, par value $0.01 per share (the “Additional Shares”) if and to the extent that the Representatives shall have determined to exercise, on behalf of the Underwriters, the right to purchase such shares of common stock granted to the Underwriters in Section 2 hereof. The Firm Shares and the Additional Shares are hereinafter collectively referred to as the “Shares.” The shares of common stock, par value $0.01 per share, of the Company to be outstanding after giving effect to the sales contemplated hereby are hereinafter referred to as the “Common Stock.”

The Company has filed with the Securities and Exchange Commission (the “Commission”) a registration statement, including a prospectus (the file number of which is set forth in Schedule I hereto), on Form S-3, relating to securities (the “Shelf Securities"), including the Shares, to be issued from time to time by the Company. The registration statement as amended to the date of this Agreement, including the information (if any) deemed to be part of the registration statement at the time of effectiveness pursuant to Rule 430B under the Securities Act of 1933, as amended (the "Securities Act”), is hereinafter referred to as the “Registration Statement,” and the related prospectus covering the Shelf Securities dated December 21, 2005 in the form first used to confirm sales of the Shares (or in the form first made available to the Underwriters by the Company to meet requests of purchasers pursuant to Rule 173 under the Securities Act) is hereinafter referred to as the “Basic Prospectus.” The Basic Prospectus, as supplemented by the prospectus supplement specifically relating to the Shares in the form first used to confirm sales of the Shares (or in the form first made available to the Underwriters by the Company to meet requests of purchasers pursuant to Rule 173 under the Securities Act) is hereinafter referred to as the “Prospectus,” and the term “preliminary prospectus” means any preliminary form of the Prospectus. For purposes of this Agreement, “free writing prospectus” has the meaning set forth in Rule 405 under the Securities Act

(which does not include communications not deemed a prospectus pursuant to Rule 134 of the Securities Act and historical issuer information meeting the requirements of Rule 433(e)(2) of the Securities Act), and “Time of Sale Prospectus” means the Basic Prospectus, each preliminary prospectus, and each free writing prospectus, if any, each identified in Schedule II hereto. As used herein, the terms “Registration Statement,” “Basic Prospectus,” “preliminary prospectus,” “Time of Sale Prospectus” and “Prospectus” shall include the documents, if any, incorporated by reference therein. The terms “supplement,” “amendment,” and “amend” as used herein with respect to the Registration Statement, the Basic Prospectus, the Time of Sale Prospectus, any preliminary prospectus or any free writing prospectus shall include all documents subsequently filed by the Company with the Commission pursuant to the Securities Exchange Act of 1934, as amended (the "Exchange Act”), that are deemed to be incorporated by reference therein.

1. Representations and Warranties. The Company represents and warrants to and agrees with each of the Underwriters that:

(a) The Registration Statement has become effective; no stop order suspending the effectiveness of the Registration Statement is in effect, and no proceedings for such purpose are pending before, or to the knowledge of the Company, threatened by the Commission. The Company is a well-known seasoned issuer (as defined in Rule 405 under the Securities Act) eligible to use the Registration Statement as an automatic shelf registration statement and the Company has not received notice that the Commission objects to the use of the Registration Statement as an automatic shelf registration statement pursuant to Rule 401(g)(2) of the Securities Act.

(b) (i) Each document, if any, filed or to be filed pursuant to the Exchange Act and incorporated by reference in the Time of Sale Prospectus or the Prospectus complied or will comply when so filed in all material respects with the Exchange Act and the applicable rules and regulations of the Commission thereunder, (ii) each part of the Registration Statement, when such part became effective, did not contain, and each such part, as amended or supplemented, if applicable, will not contain any untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein not misleading, (iii) the Registration Statement as of the date hereof does not contain any untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein not misleading, (iv) the Registration Statement and the Prospectus comply, and as amended or supplemented, if applicable, will comply in all material respects with the Securities Act and the applicable rules and regulations of the Commission thereunder, (v) the Time of Sale Prospectus does not, and at the time of each sale of the Shares in connection with the offering and at the Closing Date (as defined

in Section 4), the Time of Sale Prospectus, as then amended or supplemented by the Company, if applicable, will not, contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading and (vi) the Prospectus does not contain and, as amended or supplemented, if applicable, will not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements therein, in the light of the circumstances under which they were made, not misleading, except that the representations and warranties set forth in this paragraph do not apply to statements or omissions in the Registration Statement, the Time of Sale Prospectus or the Prospectus, each as amended or supplemented, based upon information relating to any Underwriter furnished to the Company in writing by such Underwriter through the Representatives expressly for use therein.

(c) The Company is not an “ineligible issuer” in connection with the offering pursuant to Rules 164, 405 and 433 under the Securities Act. Any free writing prospectus that the Company is required to file pursuant to Rule 433(d) under the Securities Act has been, or will be, filed with the Commission in accordance with the requirements of the Securities Act and the applicable rules and regulations of the Commission thereunder. Each free writing prospectus that the Company has filed, or is required to file, pursuant to Rule 433(d) under the Securities Act or that was prepared by or on behalf of or used or referred to by the Company complies or will comply in all material respects with the requirements of the Securities Act and the applicable rules and regulations of the Commission thereunder. Except for the free writing prospectuses, if any, identified in Schedule II hereto, and electronic road shows each furnished to you before first use, the Company has not prepared, used or referred to, and will not, without your prior consent, prepare, use or refer to, any free writing prospectus.

(d) The Company has been duly incorporated, is validly existing as a corporation in good standing under the laws of the state of Delaware, has the corporate power and authority to own its property and to conduct its business as described in the Time of Sale Prospectus, Prospectus and Registration Statement and is duly qualified to transact business and is in good standing in each jurisdiction in which the conduct of its business or its ownership or leasing of property requires such qualification, except (i) to the extent that the failure to be so qualified or be in good standing would not have a material adverse effect on the business or result of operations of the Company and its subsidiaries, taken as a whole (a “Material Adverse Effect”) and (ii) for jurisdictions not recognizing the legal concepts of good standing or qualification.

(e) Each domestic subsidiary of the Company has been duly organized, is validly existing in good standing under the laws of the jurisdiction of its organization, has the power and authority to own its property and to conduct its

business as described in the Time of Sale Prospectus, Prospectus and Registration Statement and is duly qualified to transact business and is in good standing in each jurisdiction in which the conduct of its business or its ownership or leasing of property requires such qualification, except (i) to the extent that the failure to be so qualified or be in good standing would not have a Material Adverse Effect on the Company and its subsidiaries, taken as a whole and (ii) for jurisdictions not recognizing the legal concepts of good standing or qualification. Except as set forth in the Registration Statement, Time of Sale Prospectus and Prospectus, all of the issued shares of capital stock, or equity interests, as applicable of each subsidiary of the Company have been duly and validly authorized and issued, are fully paid and non-assessable and (except (i) for directors’ qualifying share or foreign national qualifying capital stock, and (ii) as pledged to secure indebtedness of the Company and/or its subsidiaries pursuant to credit facilities, indentures and other instruments evidencing indebtedness as set forth in the Exchange Act Reports of the Company, Registration Statement, Time of Sale Prospectus and Prospectus and existing on the date hereof) are owned directly by the Company, free and clear of all liens, encumbrances, equities or claims.

(f) This Agreement has been duly authorized, executed and delivered by the Company.

(g) The authorized capital stock of the Company conforms as to legal matters to the description thereof contained in each of the Time of Sale Prospectus, the Prospectus, and the Registration Statement.

(h) The shares of Common Stock outstanding prior to the issuance of the Shares have been duly authorized and are validly issued, fully paid and non-assessable.

(i) The Shares have been duly authorized and, when issued and delivered in accordance with the terms of this Agreement, against payment of the consideration set forth herein will be validly issued, fully paid and non-assessable, and the issuance of such Shares will not be subject to any preemptive or similar rights.

(j) The execution and delivery by the Company of, and the performance by the Company of its obligations under, this Agreement will not contravene (i) any provision of the amended and restated certificate of incorporation or the amended and restated by-laws of the Company, (ii) or any agreement or other instrument binding upon the Company or any of its subsidiaries that is material to the Company and its subsidiaries, taken as a whole, (iii) or any applicable law or judgment, order or decree of any governmental body, agency or court having jurisdiction over the Company or any subsidiary except that, in the case of clauses (ii) and (iii), for any contravention that would

not have a Material Adverse Effect on the Company. No consent, approval, authorization or order of, or qualification with, any governmental body or agency is required for the performance by the Company of its obligations under this Agreement except (x) for such consent, approvals, authorizations, orders or qualifications that have been obtained or where failure to do so would not have a Material Adverse Effect on the Company and (y) for the registration of the Shares under the Securities Act and such as may be required by the securities or Blue Sky laws of the various states in connection with the offer and sale of the Shares.

(k) There has not occurred any material adverse change, or any development involving a prospective material adverse change, in the condition, financial or otherwise, or in the earnings, business or operations of the Company and its subsidiaries, taken as a whole, from that set forth in the Time of Sale Prospectus, the Prospectus, and the Registration Statement.

(l) There are no legal or governmental proceedings pending or, to the knowledge of the Company, threatened to which the Company or any of its subsidiaries is a party or to which any of the properties of the Company or any of its subsidiaries is subject other than proceedings that are disclosed or described in all material respects in the Registration Statement, Time of Sale Prospectus, or the Prospectus and proceedings that are not expected to have a Material Adverse Effect, and there are no statutes, regulations, contracts or other documents that are required to be described in the Registration Statement, Time of Sale Prospectus, or the Prospectus or to be filed as exhibits to the Registration Statement that are not described in all material respects or filed, or incorporated by reference as required.

(m) Each preliminary prospectus supplement filed pursuant to Rule 424 under the Securities Act, complied when so filed in all material respects with the Securities Act and the applicable rules and regulations of the Commission thereunder.

(n) The Company is not, and after giving effect to the offering and sale of the Shares and the application of the proceeds thereof as described in the Prospectus will not be, required to register as an “investment company” as such term is defined in the Investment Company Act of 1940, as amended.

(o) Neither the Company nor any subsidiary of the Company is, or after giving effect to the offering and sale of the Shares and the application of the proceeds thereof as described in the Prospectus, will be, subject to regulation under the Public Utility Holding Company Act of 1935 (“PUHCA”) as a “holding company,” a “public-utility company” or, to the knowledge of Company, a “subsidiary company” of a “holding company,” in each case as such terms are

defined in PUHCA; provided that after February 8, 2006, the representation and warranty of this section (0) shall be of no force and effect.

(p) Except as set forth in the Registration Statement, the Time of Sale Prospectus, or Prospectus, each subsidiary of the Company that is subject to regulation as a “public utility” as such term is defined in the Federal Power Act (“FPA”) has an order from the Federal Energy Regulatory Commission, not subject to any pending challenge, investigation, complaint, or other proceeding (other than generic proceedings generally applicable in the industry) (i) authorizing such subsidiary to engage in wholesale sales of electricity and, to the extent permitted under its market-based rate tariff, other transactions at market-based rates and (y) granting such waivers and blanket authorizations as are customarily granted to entities with market-based rate authority, including blanket authorizations to issue securities and to assume liabilities pursuant to Section 204 of the FPA.

(q) With respect to any subsidiary that owns a “Qualifying Facility” (“QF”) as defined under the Public Utility Regulatory Policies Act and the current rules and regulations promulgated thereunder (“PURPA”), such facility is a QF under PURPA.

(r) Except as disclosed in the Registration Statement, the Time of Sale Prospectus, or Prospectus, and except for such matters as would not, individually or in the aggregate, result in a Material Adverse Effect, the Company or any of its subsidiaries (1) are conducting and have conducted their businesses, operations and facilities in compliance with Environmental Laws (as defined below); (2) have duly obtained, possess, maintain in full force and effect, and have fulfilled and performed all of their obligations under any and all permits, licenses or registrations required under Environmental Law (“Environmental Permits”); (3) have not received any notice from a governmental authority or any other third party alleging any violation of Environmental Law or liability thereunder; (4) are not subject to any pending or, to the best knowledge of the Company or any of its subsidiaries, threatened claim in writing or other legal proceeding under any Environmental Laws against the Company or any of its subsidiaries; and (5) do not have knowledge of any applicable Environmental Laws, or any unsatisfied conditions in an Environmental Permit, that, individually or in the aggregate, can reasonably be expected to require any material capital expenditures for either the installation of new pollution control equipment, or a switch in a project’s fuel or any other material modification of current operations in order to maintain the Company’s or the subsidiaries’ compliance with Environmental Law. As used in this paragraph, “Environmental Laws” means any and all applicable foreign, federal, state and local laws and regulations, or any enforceable administrative or judicial interpretation thereof, relating to pollution or the protection of human health or the environment, including, without limitation, those relating to (i)

emissions, discharges or releases of Hazardous Substances into ambient air, surface water, groundwater or land, (ii) the generation, manufacture, processing, distribution, use, treatment, storage, disposal, release, transport or handling of, or exposure to, Hazardous Substances, (iii) the protection of wildlife or endangered or threatened species, or (iv) the investigation, remediation or cleanup of any Hazardous Substances. As used in this paragraph, “Hazardous Substances” means pollutants, contaminants, hazardous substances, materials or wastes, petroleum, petroleum products and their breakdown constituents, or any other chemical substance regulated under Environmental Laws.

(s) Except as described in the Time of Sale Prospectus, the Prospectus, and the Registration Statement, the Company has not sold, issued or distributed any shares of Common Stock during the six-month period preceding the date hereof, including any sales pursuant to Rule 144A under, or Regulation D or S of, the Securities Act, other than shares issued pursuant to employee benefit plans, qualified stock option plans or other employee compensation plans or pursuant to outstanding options, rights or warrants.

2. Agreements to Sell and Purchase. The Company hereby agrees to sell to the several Underwriters, and each Underwriter, upon the basis of the representations and warranties herein contained, but subject to the conditions hereinafter stated, agrees, severally and not jointly, to purchase from the Company the respective numbers of Firm Shares set forth in Schedule I hereto opposite its name at $48.750 a share (the “Purchase Price”).

On the basis of the representations and warranties contained in this Agreement, and subject to its terms and conditions, the Company agrees to sell to the Underwriters the Additional Shares, and the Underwriters shall have the right to purchase, severally and not jointly, up to 3,128,259 Additional Shares at the Purchase Price. You may exercise this right on behalf of the Underwriters in whole or from time to time in part by giving written notice not later than 30 days after the date of the Final Prospectus Supplement. Any exercise notice shall specify the number of Additional Shares to be purchased by the Underwriters and the date on which such shares are to be purchased. Each purchase date must be at least one business day after the written notice is given and may not be earlier than the closing date for the Firm Shares nor later than ten business days after the date of such notice. Additional Shares may be purchased as provided in Section 4 hereof solely for the purpose of covering over-allotments made in connection with the offering of the Firm Shares. On each day, if any, that Additional Shares are to be purchased (an “Option Closing Date”), each Underwriter agrees, severally and not jointly, to purchase the number of Additional Shares (subject to such adjustments to eliminate fractional shares as you may determine) that bears the same proportion to the total number of Additional Shares to be purchased on such

Option Closing Date as the number of Firm Shares set forth in Schedule I hereto opposite the name of such Underwriter bears to the total number of Firm Shares.

3. Terms of Public Offering. The Company is advised by you that the Underwriters propose to make a public offering of their respective portions of the Shares as soon after this Agreement has become effective as in your judgment is advisable. The Company is further advised by you that the Shares are to be offered to the public initially at $48.750 a share (the “Public Offering Price”) and to certain dealers selected by the Representatives at a price that represents a concession not in excess of $0.880 a share under the Public Offering Price.

4. Payment and Delivery. Payment for the Firm Shares shall be made to the Company by wire transfer in immediately available funds, or other funds immediately available in New York City on the closing date and time set forth in Schedule I hereto, or at such other time on the same or such other date, not later than the fifth business day thereafter, as may be designated by you in writing. The time and date of such payment are hereinafter referred to as the “Closing Date.”

Payment for any Additional Shares shall be made to the Company by wire transfer in immediately available funds, or other funds immediately available in New York City against delivery of such Additional Shares for the respective accounts of the several Underwriters at 10:00 a.m., New York City time, on the applicable Option Closing Date or at such other time on the same or on such other date, in any event not later than February 25, 2006, as shall be designated in writing by the Representatives.

The Firm Shares and Additional Shares shall be registered in such names and in such denominations as you shall request in writing not later than one full business day prior to the Closing Date or the applicable Option Closing Date, as the case may be. The Firm Shares and Additional Shares shall be delivered to you on the Closing Date or an Option Closing Date, as the case may be, for the respective accounts of the several Underwriters, with any transfer taxes payable in connection with the transfer of the Shares to the Underwriters duly paid, against payment of the Purchase Price therefor.

5. Conditions to the Underwriters’ Obligations. The several obligations of the Underwriters are subject to the following conditions:

(a) Subsequent to the execution and delivery of this Agreement and prior to the Closing Date:

(i) there shall not have occurred any downgrading, nor shall the Company have received any notice from any “nationally recognized

statistical rating organization,” as such term is defined for purposes of Rule 436(g)(2) under the Securities Act of any intended or potential downgrading or of any review for a possible change that does not indicate the direction of the possible change, in the rating accorded the Company or any of the securities of the Company or any of its subsidiaries or in the rating outlook for the Company; and

(ii) there shall not have occurred any change, or any development involving a prospective change, in the condition, financial or otherwise, or in the earnings, business or operations of the Company and its subsidiaries, taken as a whole, from that set forth in the Time of Sale Prospectus that, in the judgment of the Representatives, is material and adverse and that makes it, in the judgment of the Representatives, impracticable or inadvisable to proceed with the offer, sale and delivery of the Shares, or market the Shares on the terms and in the manner contemplated in this Agreement and the Time of Sale Prospectus.

(b) The Underwriters shall have received on the Closing Date a certificate, dated the Closing Date and signed by an executive officer of the Company, to the effect set forth in Section 5(a)(i) above and to the effect that the representations and warranties of the Company contained in this Agreement that are not qualified by materiality are true and correct in all material respects, and that the representations and warranties of the Company contained in this Agreement that are qualified by materiality are true and correct, in each case, as of the Closing Date, and that the Company has complied in all material respects with all of the agreements and satisfied all of the conditions on its part to be performed or satisfied hereunder on or before the Closing Date.

The officer signing and delivering such certificate may rely upon the best of his or her knowledge as to proceedings threatened.

(c) The Underwriters shall have received on the Closing Date an opinion of and a negative assurance letter of Skadden, Arps, Slate, Xxxxxxx & Xxxx LLP and/or Xxxxxxxx & Xxxxx LLP, outside counsel for the Company, dated the Closing Date, to the effect set forth on Schedule III. Additionally, Xxx X’Xxxxx, General Counsel of the Company, and other local counsel of the Company shall provide opinions, dated the Closing Date, as the Representatives shall reasonably request.

(d) The Underwriters shall have received on the Closing Date an opinion and a negative assurance letter of Xxxxxx & Xxxxxxx LLP, counsel for the Underwriters, dated the Closing Date to the effect set forth on Schedule III.

(e) The Underwriters shall have received, on each of the date hereof and the Closing Date, a letter dated the date hereof or the Closing Date, as the case may be, in form and substance satisfactory to the Underwriters, from KPMG LLP, PricewaterhouseCoopers LLP, and Deloitte and Touche LLP, independent public accountants, containing statements and information of the type ordinarily included in accountants’ “comfort letters” to underwriters with respect to the financial statements and certain financial information contained in the Registration Statement, the Time of Sale Prospectus and the Prospectus; provided that the letter delivered on the Closing Date shall use a “cut-off date” not earlier than the date hereof.

(f) The “lock-up” agreements, each substantially in the form of Exhibit A hereto, between you and certain officers and directors of the Company relating to sales and certain other dispositions of shares of Common Stock or certain other securities, delivered to you on or before the date hereof, shall be in full force and effect on the Closing Date.

The several obligations of the Underwriters to purchase Additional Shares hereunder are subject to the delivery to you on the applicable Option Closing Date of such documents as you may reasonably request with respect to the good standing of the Company, the due authorization and issuance of the Additional Shares to be sold on such Option Closing Date and other matters related to the issuance of such Additional Shares.

6. Covenants of the Company. The Company covenants with each Underwriter as follows:

(a) To furnish to the Representatives, without charge, a conformed copy of the Registration Statement (without exhibits thereto) and to deliver to each of the Underwriters during the period mentioned in Section 6(f) below, as many copies of the Time of Sale Prospectus, the Prospectus, any documents incorporated therein by reference therein and any supplements and amendments thereto or to the Registration Statement as the Representatives may reasonably request; provided, that the Company shall not be required to furnish copies of the Prospectus if the conditions of Rule 172(c) under the Securities Act are satisfied by the Company.

(b) Before amending or supplementing the Registration Statement, the Time of Sale Prospectus or the Prospectus, to furnish to the Representatives a copy of each such proposed amendment or supplement and not to file any such proposed amendment or supplement to which the Representatives reasonably object.

(c) To furnish to the Representatives a copy of each proposed free writing prospectus to be prepared by or on behalf of, used by, or referred to by the Company and not to use or refer to any proposed free writing prospectus to which the Representatives reasonably object.

(d) Not to take any action that would result in an Underwriter or the Company being required to file with the Commission pursuant to Rule 433(d) under the Securities Act a free writing prospectus prepared by or on behalf of the Underwriters that the Underwriters otherwise would not have been required to file thereunder. For the avoidance of doubt, this paragraph (d) shall not be applicable to the January 25 Issuer FWP and the January 26 Issuer FWP (each as defined below).

(e) If the Time of Sale Prospectus is being used to solicit offers to buy the Shares at a time when the Prospectus is not yet available to prospective purchasers and any event shall occur or condition exist as a result of which the Time of Sale Prospectus would include an untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary in order to make the statements therein, in the light of the circumstances, not misleading, or if any event shall occur or condition exist as a result of which, in the reasonable opinion of counsel for the Underwriters or counsel for the Company, the Time of Sale Prospectus conflicts with the information contained in the Registration Statement then on file, or if, in the reasonable opinion of counsel for the Underwriters or counsel for the Company, it is necessary to amend or supplement the Time of Sale Prospectus to comply with applicable law, forthwith to prepare, file with the Commission and furnish, at its own expense, to the Underwriters and to any dealer upon request, either amendments or supplements to the Time of Sale Prospectus so that either the statements in the Time of Sale Prospectus as so amended or supplemented will not, in the light of the circumstances when delivered to a prospective purchaser, be misleading or so that the Time of Sale Prospectus, as amended or supplemented, will no longer conflict with the Registration Statement, or so that the Time of Sale Prospectus, as amended or supplemented, will comply with applicable law.

(f) If, during such period after the first date of the public offering of the Shares as in the reasonable opinion of counsel for the Underwriters the Prospectus (or in lieu thereof the notice referred to in Rule 173(a) under the Securities Act) is required by law to be delivered in connection with sales by an Underwriter or dealer, any event shall occur or condition exist as a result of which, in the reasonable opinion of counsel for the Underwriters or counsel for the Company, the Prospectus would include and untrue statement of a material fact or omit to state a material fact required to be state therein of necessary in order to make the statements therein, in the light of the circumstances when the Prospectus (or in lieu thereof the notice referred to in Rule 173(a) under the

Securities Act) is delivered to a purchaser, not misleading, or if, in the reasonable opinion of counsel for the Underwriters or counsel for the Company, it is necessary to amend or supplement the Prospectus to comply with applicable law, forthwith to prepare, file with the Commission and furnish, at its own expense, to the Underwriters and to the dealers (whose names and addresses you will furnish to the Company) to which Shares may have been sold by you on behalf of the Underwriters and to any other dealers upon request, either amendments or supplements to the Prospectus so that the statements in the Prospectus as so amended or supplemented will not, in the light of the circumstances when the Prospectus (or in lieu thereof the notice referred to in Rule 173(a) under the Securities Act) is delivered to a purchaser, be misleading or so that the Prospectus, as amended or supplemented, will comply with applicable law; provided, that the Company shall not be required to furnish copies of the Prospectus if the conditions of Rule 172(c) under the Securities Act are satisfied by the Company.

(g) To use its reasonable best efforts to qualify the Shares for offer and sale under the securities or Blue Sky laws of such jurisdictions as you shall reasonably request; provided, however, that nothing contained herein shall require the Company to qualify to do business in any jurisdiction, to execute a general consent to service of process in any state or to subject itself to taxation in any jurisdiction in which it is otherwise not so subject.

(h) To make generally available to the Company’s security holders and to the Representatives as soon as practicable an earning statement covering a period of at least twelve months beginning with the first fiscal quarter of the Company occurring after the date of this Agreement which shall satisfy the provisions of Section 11(a) of the Securities Act and the rules and regulations of the Commission thereunder.

(i) Whether or not the transactions contemplated in this Agreement are consummated or this Agreement is terminated, to pay or cause to be paid the costs and expenses relating to the following matters: (i) the fees, disbursements and expenses of the Company’s counsel and the Company’s accountants in connection with the registration and delivery of the Shares under the Securities Act and all other fees or expenses in connection with the preparation and filing of the Registration Statement, any preliminary prospectus, the Time of Sale Prospectus, the Prospectus, any free writing prospectus prepared by or on behalf of, used by, or referred to by the Company and amendments and supplements to any of the foregoing, including the filing fees payable to the Commission relating to the Shares (within the time required by Rule 456 (b)(1), if applicable), all printing costs associated therewith, and the mailing and delivering of copies thereof to the Underwriters and dealers, in the quantities hereinabove specified, (ii) all costs and expenses related to the transfer and delivery of the Shares to the

Underwriters, including any transfer or other taxes payable thereon, (iii) the cost of printing or producing any Blue Sky or legal investment memorandum in connection with the offer and sale of the Shares under state securities laws and all expenses in connection with the qualification of the Shares for offer and sale under state securities laws as provided in Section 6(f) hereof, including filing fees and the reasonable fees and disbursements of counsel for the Underwriters in connection with such qualification and in connection with the Blue Sky or legal investment memorandum, which shall be $25,000 in the aggregate for this offering and the concurrent offerings by the Company of its high yield notes and mandatory convertible preferred stock, (iv) all costs and expenses incident to listing the Shares on the NYSE, (v) the cost of the preparation, issuance and delivery of the Shares, (vi) the costs and charges of any transfer agent, registrar or depositary, (vii) the document production charges and expenses associated with printing this Agreement and (viii) all other costs and expenses incident to the performance of the obligations of the Company hereunder for which provision is not otherwise made in this Section; provided however that any costs and expenses of the Company relating to investor presentations on any “road show” undertaken in connection with the marketing or the offering of the Shares, including, without limitation, expenses associated with the preparation or dissemination of any electronic road show, expenses associated with the production of road show slides and graphics, fees and expenses of any consultants engaged in connection with the road show presentations, travel and lodging expenses of the representatives and officers of the Company and any such consultants, and the cost of any aircraft chartered in connection with the road show, shall be paid or caused to be paid by the Underwriters. It is understood, however, that except as provided in this Section, Section 8 entitled “Indemnity and Contribution,” and the last paragraph of Section 10 below, the Underwriters will pay all of their costs and expenses, including fees and disbursements of their counsel, transfer taxes payable on resale of any of the Shares by them and any advertising expenses connected with any offers they may make.

(j) (i) To prepare the issuer free writing prospectus (as defined in Rule 433 promulgated under the Securities Act) attached hereto as Exhibit B (the “January 25 Issuer FWP”), and to file such January 25 Issuer FWP as soon as reasonably practicable thereafter, and (ii) to prepare the issuer free writing prospectus (as defined in Rule 433 promulgated under the Securities Act) attached hereto as Exhibit C (the “January 26 Issuer FWP”), and to file such January 26 Issuer FWP as soon as reasonably practicable on January 26, 2006.

(k) If the third anniversary of the initial effective date of the Registration Statement occurs before all the Shares have been sold by the Underwriters, prior to the third anniversary to file a new shelf registration statement and to take any other action necessary to permit the public offering of the Shares to continue without interruption; references herein to the Registration

Statement shall include the new registration statement declared effective by the Commission.

(l) During the period beginning on the date hereof and continuing to and including the Closing Date, offer, pledge, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase, lend, or otherwise dispose of any equity securities of the Company or warrants to purchase or otherwise acquire equity securities of the Company substantially similar to the Shares (other than (i) the Shares (ii) securities or warrants permitted with the prior written consent of the Representatives (iii) the issuance by the Company of shares of Common Stock upon the exercise of an option or warrant or the conversion of a security outstanding on the date hereof, (iv) the grant by the Company of employees, officer or director stock options, the issuance by the Company of any shares of Common Stock upon the exercise of any option (regardless of when issued) under any employee, officer or director stock option or similar benefit plan in effect on the date hereof or (v) the issuance by the Company of shares of Common Stock, stock appreciation rights or common stock equivalents or warrants, rights or options to purchase nay of the foregoing, pursuant to any employee, officer or director stock option in effect on the date hereof, stock purchase or similar benefit plan, provided that nothing in this paragraph (l) shall be construed as a limitation (1) on the Company’s ability to consummate, or prevent the Company from consummating the Acquisition and related transactions and the financing and refinancing transactions as described in the Time of Sale Prospectus and the Final Prospectus and (2) on the provisos in paragraph (m) below.

Subject to paragraph (m) below, the Company also covenants with each Underwriter that, without the prior written consent of the Representatives on behalf of the Underwriters, it will not, during the period ending 90 days after the date of the Prospectus, (1) offer, pledge, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase, lend, or otherwise transfer or dispose of, directly or indirectly, any shares of Common Stock or any securities convertible into or exercisable or exchangeable for Common Stock or (2) enter into any swap or other arrangement that transfers to another, in whole or in part, any of the economic consequences of ownership of the Common Stock, whether any such transaction described in clause (1) or (2) above is to be settled by delivery of Common Stock or such other securities, in cash or otherwise.

The restrictions contained in the preceding paragraph shall not apply to (a) the Shares to be sold hereunder, (b) the issuance by the Company of shares of Common Stock upon the exercise of an option or warrant or the conversion of a security outstanding on the date hereof (c) the grant by the Company of employees, officer or director stock options, the issuance by the Company of any

shares of Common Stock upon the exercise of any option (regardless of when issued) under any employee, officer or director stock option or similar benefit plan in effect on the date hereof and (d) the issuance by the Company of shares of Common Stock, stock appreciation rights or common stock equivalents or warrants, rights or opinions to purchase any of the foregoing, pursuant to any employee, officer or director stock option, stock purchase or similar benefit plan in effect on the date hereof. Notwithstanding the foregoing, if (1) during the last 17 days of the 90-day restricted period the Company issues an earnings release or material news or a material event relating to the Company occurs; or (2) prior to the expiration of the 90-day restricted period, the Company announces that it will release earnings results during the 16-day period beginning on the last day of the 90-day period, the restrictions imposed by this agreement shall continue to apply until the expiration of the 18-day period beginning on the issuance of the earnings release or the occurrence of the material news or material event. The Company shall promptly notify the Representatives of any earnings release, news or event that may give rise to an extension of the initial 90-day restricted period.

(m) Not to waive or amend Section 2.1 of the Investor Rights Agreement (as such term is defined in the acquisition agreement (the “Acquisition Agreement”) of Texas Genco LLC (the "Acquisition") and in the form attached as Exhibit C to the Acquisition Agreement as in effect on the date hereof), among the Company and the sellers in the Acquisition without the prior written consent of the Representatives (which consent may not be unreasonably withheld) during the period ending 90 days after the date of the Prospectus, provided however that (i) from and after the date that is 14 days after the date hereof, the Company may, at its election and without the need for any consent of the Representatives, permit and facilitate the sale or other disposition of an aggregate of up to 600,000 shares of Common Stock issued to former members of Texas Genco management pursuant to the Acquisition Agreement or as a result of the Acquisition, including by means of filing, and having declared effective, a shelf registration statement covering such sales (or by filing a prospectus supplement with respect to an existing Company shelf registration statement), by repurchasing such shares from the holders thereof or by any other means deemed necessary or appropriate by the Company, in its discretion and (ii) this paragraph (m) shall not prohibit, and no consent of the Representatives shall be required for, any amendment to the Investor Rights Agreement for the purpose of, or any waiver of the terms of the Investor Rights Agreement intended to permit, the Transfer of Registrable Securities by a Stockholder to an Affiliate of such Stockholder prior to the expiration of the Lock-Up Period (capitalized terms used in the preceding proviso and not otherwise defined herein shall have the respective meanings ascribed to such terms in the Investor Rights Agreement), provided that such Affiliate agrees to be bound by the provisions of Section 2.1 of the Investors Rights Agreement (as defined in the Acquisition Agreement).

7. Covenants of the Underwriters. Each Underwriter severally covenants with the Company not to take any action that would result in the Company being required to file with the Commission under Rule 433(d) a free writing prospectus prepared by or on behalf of such Underwriter that otherwise would not be required to be filed by the Company thereunder, but for the action of the Underwriter. For the avoidance of doubt, this Section 7 shall not restrict the dissemination by the Underwriters of the January 25 Issuer FWP or the January 26 Issuer FWP.

8. Indemnity and Contribution. (a) The Company agrees to indemnify and hold harmless each Underwriter, each person, if any, who controls any Underwriter within the meaning of either Section 15 of the Securities Act or Section 20 of the Exchange Act and each affiliate of any Underwriter within the meaning of Rule 405 under the Securities Act (provided that the Company’s indemnification obligation shall not extend to any free writing prospectus required to be filed by the Company due to an Underwriter’s breach of Section 7) from and against any and all losses, claims, damages and liabilities (including, without limitation, any legal or other expenses reasonably incurred in connection with defending or investigating any such action or claim) caused by any untrue statement or alleged untrue statement of a material fact contained in the Registration Statement or any amendment thereof, any preliminary prospectus, the Time of Sale Prospectus, any free writing prospectus that the Company has filed, or is required to file, pursuant to Rule 433(d) under the Securities Act or the Prospectus or any amendment or supplement thereto (if the Company furnished any amendments or supplements thereto), or caused by any omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the statements therein, (i) with respect to the Registration Statement or any amendment thereof, not misleading, and (ii) with respect to any preliminary prospectus, the Time of Sale Prospectus, any free writing prospectus that the Company has filed, or is required to file, pursuant to Rule 433(d) under the Securities Act or the Prospectus or any amendment or supplement thereto (if the Company furnished any amendments or supplements thereto), not misleading in light of the circumstances under which they were made, except in each case insofar as such losses, claims, damages or liabilities are caused by any such untrue statement or omission or alleged untrue statement or omission based upon information relating to any Underwriter furnished to the Company in writing by such Underwriter through the Representatives expressly for use therein.

(b) Each Underwriter agrees, severally and not jointly, to indemnify and hold harmless the Company, its directors, its officers who sign the Registration Statement and each person, if any, who controls the Company within the meaning of either Section 15 of the Securities Act or Section 20 of the Exchange Act to the same extent as the foregoing indemnity from the Company to such Underwriter, but only with reference to information relating to such

Underwriter furnished to the Company in writing by such Underwriter through the Representatives expressly for use in the Registration Statement, any preliminary prospectus, the Time of Sale Prospectus, any other free writing prospectus that the Company has filed, or is required to file, pursuant to Rule 433(d) under the Securities Act or the Prospectus or any amendment or supplement thereto.

(c) In case any proceeding (including any governmental investigation) shall be instituted involving any person in respect of which indemnity may be sought pursuant to Section 8(a) or 8(b), such person (the “indemnified party”) shall promptly notify the person against whom such indemnity may be sought (the “indemnifying party”) in writing and the indemnifying party, upon request of the indemnified party, shall retain counsel chosen by the indemnifying party and reasonably satisfactory to the indemnified party to represent the indemnified party and any others entitled to indemnification pursuant to this Section 8 the indemnifying party may designate in such proceeding and shall pay the reasonably incurred fees and expenses of such counsel related to such proceeding as incurred. In any such proceeding, any indemnified party shall have the right to retain its own counsel, but the reasonably incurred fees and expenses of such counsel shall be at the expense of such indemnified party unless (i) the indemnifying party and the indemnified party shall have mutually agreed to the retention of such counsel or (ii) the named parties to any such proceeding (including any impleaded parties) include both the indemnifying party and the indemnified party and representation of both parties by the same counsel would be inappropriate due to actual or potential differing interests between them. It is understood and agreed that the indemnifying party shall not, in connection with any proceeding or related proceedings in the same jurisdiction, be liable for the reasonably incurred fees and expenses of more than one separate firm (in addition to any local counsel) for all such indemnified parties and that all such reasonably incurred fees and expenses shall be reimbursed as they are incurred. Such firm shall be designated in writing the Representatives, in the case of parties indemnified pursuant to Section 8(a), and by the Company, in the case of parties indemnified pursuant to Section 8(b). The indemnifying party shall not be liable for any settlement of any proceeding effected without its written consent, but if settled with such consent or if there be a final judgment for the plaintiff, the indemnifying party agrees to indemnify the indemnified party from and against any loss or liability by reason of such settlement or judgment. No indemnifying party shall, without the prior written consent of the indemnified party, effect any settlement of any pending or threatened proceeding in respect of which any indemnified party is or could have been a party and indemnity could have been sought hereunder by such indemnified party, unless such settlement includes an unconditional release of such indemnified party from all liability on claims that are the subject matter of such proceeding.

(d) To the extent the indemnification provided for in Section 8(a) or 8(b) is unavailable to an indemnified party or insufficient in respect of any losses, claims, damages or liabilities referred to therein, then each indemnifying party under such paragraph, in lieu of indemnifying such indemnified party thereunder, shall contribute to the amount paid or payable by such indemnified party as a result of such losses, claims, damages or liabilities (i) in such proportion as is appropriate to reflect the relative benefits received by the indemnifying party or parties on the one hand and the indemnified party or parties on the other hand from the offering of the Shares or (ii) if the allocation provided by clause 8(d)(i) above is not permitted by applicable law, in such proportion as is appropriate to reflect not only the relative benefits referred to in clause 8(d)(i) above but also the relative fault of the indemnifying party or parties on the one hand and of the indemnified party or parties on the other hand in connection with the statements or omissions that resulted in such losses, claims, damages or liabilities, as well as any other relevant equitable considerations. The relative benefits received by the Company on the one hand and the Underwriters on the other hand in connection with the offering of the Shares shall be deemed to be in the same respective proportions as the net proceeds from the offering of the Shares (before deducting expenses) received by the Company and the total underwriting discounts and commissions received by the Underwriters, in each case as set forth in the table on the cover of the Prospectus, bear to the aggregate Public Offering Price of the Shares. The relative fault of the Company on the one hand and the Underwriters on the other hand shall be determined by reference to, among other things, whether the untrue or alleged untrue statement of a material fact or the omission or alleged omission to state a material fact relates to information supplied by the Company or by the Underwriters and the parties’ relative intent, knowledge, access to information and opportunity to correct or prevent such statement or omission. The Underwriters’ respective obligations to contribute pursuant to this Section 8 are several in proportion to the respective number of Shares they have purchased hereunder, and not joint.

(e) The Company and the Underwriters agree that it would not be just or equitable if contribution pursuant to this Section 8 were determined by pro rata allocation (even if the Underwriters were treated as one entity for such purpose) or by any other method of allocation that does not take account of the equitable considerations referred to in Section 8(d). The amount paid or payable by an indemnified party as a result of the losses, claims, damages and liabilities referred to in Section 8(d) shall be deemed to include, subject to the limitations set forth above, any legal or other expenses reasonably incurred by such indemnified party in connection with investigating or defending any such action or claim. Notwithstanding the provisions of this Section 8, no Underwriter shall be required to contribute any amount in excess of the amount by which the total price at which the Shares underwritten by it and distributed to the public were offered to

the public exceeds the amount of any damages that such Underwriter has otherwise been required to pay by reason of such untrue or alleged untrue statement or omission or alleged omission. No person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Securities Act) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation. The remedies provided for in this Section 8 are not exclusive and shall not limit any rights or remedies which may otherwise be available to any indemnified party at law or in equity.

(f) The indemnity and contribution provisions contained in this Section 8 and the representations, warranties and other statements of the Company contained in this Agreement shall remain operative and in full force and effect regardless of (i) any termination of this Agreement, (ii) any investigation made by or on behalf of any Underwriter, any person controlling any Underwriter or any affiliate of any Underwriter or by or on behalf of the Company, its officers or directors or any person controlling the Company and (iii) acceptance of and payment for any of the Shares.

9. Termination. The Underwriters may terminate this Agreement by notice given by the Representatives to the Company, if after the execution and delivery of this Agreement and prior to the Closing Date (i) trading generally shall have been suspended or materially limited on, or by, as the case may be, any of the New York Stock Exchange, or the Nasdaq National Market, (ii) trading of any securities of the Company shall have been suspended on the New York Stock Exchange, (iii) a material disruption in securities settlement, payment or clearance services in the United States shall have occurred, (iv) any moratorium on commercial banking activities shall have been declared by Federal or New York State authorities or (v) there shall have occurred any outbreak or escalation of hostilities, or any change in financial markets or any calamity or crisis that, in your judgment, is material and adverse and which, singly or together with any other event specified in this clause (v), makes it, in the Representatives judgment, impracticable or inadvisable to proceed with the offer, sale or delivery of the Shares on the terms and in the manner contemplated in the Time of Sale Prospectus or the Prospectus.

10. Effectiveness; Defaulting Underwriters. This Agreement shall become effective upon the execution and delivery hereof by the parties hereto.

If, on the Closing Date or an Option Closing Date, as the case may be, any one or more of the Underwriters shall fail or refuse to purchase Shares that it has or they have agreed to purchase hereunder on such date, and the aggregate number of Shares which such defaulting Underwriter or Underwriters agreed but failed or refused to purchase is not more than one-tenth of the aggregate number of the Shares to be purchased on such date, the other Underwriters shall be

obligated severally in the proportions that the number of Firm Shares set forth opposite their respective names in Schedule I bears to the aggregate number of Firm Shares set forth opposite the names of all such non-defaulting Underwriters, or in such other proportions as you may specify, to purchase the Shares which such defaulting Underwriter or Underwriters agreed but failed or refused to purchase on such date; provided that in no event shall the number of Shares that any Underwriter has agreed to purchase pursuant to this Agreement be increased pursuant to this Section 10 by an amount in excess of one-ninth of such number of Shares without the written consent of such Underwriter. If, on the Closing Date, any Underwriter or Underwriters shall fail or refuse to purchase Firm Shares and the aggregate number of Firm Shares with respect to which such default occurs is more than one-tenth of the aggregate number of Firm Shares to be purchased on such date, and arrangements satisfactory to you and the Company for the purchase of such Firm Shares are not made within 36 hours after such default, this Agreement shall terminate without liability on the part of any non-defaulting Underwriter or the Company. In any such case either you or the Company shall have the right to postpone the Closing Date, but in no event for longer than seven days, in order that the required changes, if any, in the Registration Statement, in the Time of Sale Prospectus, in the Prospectus or in any other documents or arrangements may be effected. If, on an Option Closing Date, any Underwriter or Underwriters shall fail or refuse to purchase Additional Shares and the aggregate number of Additional Shares with respect to which such default occurs is more than one-tenth of the aggregate number of Additional Shares to be purchased on such Option Closing Date, the non-defaulting Underwriters shall have the option to (i) terminate their obligation hereunder to purchase the Additional Shares to be sold on such Option Closing Date or (ii) purchase not less than the number of Additional Shares that such non-defaulting Underwriters would have been obligated to purchase in the absence of such default. Any action taken under this paragraph shall not relieve any defaulting Underwriter from liability in respect of any default of such Underwriter under this Agreement.

If this Agreement shall be terminated by the Underwriters, or any of them, because of any failure or refusal on the part of the Company to comply with the terms or to fulfill any of the conditions of this Agreement (other than by reason of a default by any of the Underwriters described in the preceding paragraph), or if for any reason the Company shall be unable to perform its obligations under this Agreement, the Company will reimburse the Underwriters or such Underwriters as have so terminated this Agreement with respect to themselves, severally, for all out-of-pocket expenses (including the fees and disbursements of their counsel) reasonably incurred by such Underwriters in connection with this Agreement or the offering contemplated hereunder.

11. Entire Agreement. (a) This Agreement, together with any contemporaneous written agreements and any prior written agreements (to the

extent not superseded by this Agreement) that relate to the offering of the Shares, represents the entire agreement between the Company and the Underwriters with respect to the preparation of any preliminary prospectus, the Time of Sale Prospectus, the Prospectus, the conduct of the offering, and the purchase and sale of the Shares.

(b) The Company acknowledges that in connection with the offering of the Shares: (i) the Underwriters have acted at arms length, are not agents of, and owe no fiduciary duties to, the Company or any other person, (ii) the Underwriters owe the Company only those duties and obligations set forth in this Agreement and prior written agreements (to the extent not superseded by this Agreement), if any, and (iii) the Underwriters may have interests that differ from those of the Company. The Company waives to the full extent permitted by applicable law any claims it may have against the Underwriters arising from an alleged breach of fiduciary duty in connection with the offering of the Shares.

12. Counterparts. This Agreement may be signed in two or more counterparts, each of which shall be an original, with the same effect as if the signatures thereto and hereto were upon the same instrument.

13. Applicable Law. This Agreement shall be governed by and construed in accordance with the internal laws of the State of New York.

14. Headings. The headings of the sections of this Agreement have been inserted for convenience of reference only and shall not be deemed a part of this Agreement.

15. Notices. All communications hereunder shall be in writing and effective only upon receipt and if to the Underwriters shall be delivered, mailed or sent to you at the address set forth in Schedule I hereto; and if to the Company shall be delivered, mailed or sent to the address set forth in Schedule I hereto.


Very truly yours, NRG ENERGY, INC.
By:	/s/ Xxxxxx X. Xxxxxxxx
	Name:	Xxxxxx X. Xxxxxxxx
	Title:	Vice President and Treasurer


Accepted as of the date hereof XXXXXX XXXXXXX & CO. INCORPORATED
By:	/s/ Xxxx X. Xxxxxx
	Name:	Xxxx X. Xxxxxx
	Title:	Executive Director


CITIGROUP GLOBAL MARKETS INC.
By:	/s/ Woo-Xxxx Xxxxx
	Name:	Woo-Xxxx Xxxxx
	Title:	Director Acting severally on behalf of themselves and several Underwriters named in Schedule I hereto

SCHEDULE I


	Number of Firm
	Shares To Be
Underwriter	Purchased
Xxxxxx Xxxxxxx & Co. Incorporated		7,768,508
Citigroup Global Markets Inc.		7,768,508
Xxxxxx Brothers Inc.		1,564,129
Bank of America Securities LLC		938,478
Deutsche Bank Securities Inc.		938,478
Xxxxxxx Lynch, Pierce, Xxxxxx & Xxxxx Incorporated		938,478
Xxxxxxx Sachs & Co.		938,478

Total:		20,855,057

I-1

SCHEDULE II

Time of Sale Prospectus


1.		Preliminary Prospectus issued January 5, 2006


2.		January 25 Issuer FWP


3.		January 26 Issuer FWP


4.		The issuer free writing prospectus filed on Form 8-K, dated January 24, 2006 (file number 333-130549)


5.		The Company’s road show with respect to the offering that constitutes a written communication pursuant to Rule 433 promulgated under the Securities Act of 1933, as amended

II-1

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Table of Contents

1,016,684,029 20,855,057 Shares NRG Energy, Inc. COMMON STOCK UNDERWRITING AGREEMENT

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