UNITED STATES

SECURITIES AND EXCHANGE
COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

Item 1.

Security and Issuer

This statement relates to the common stock, $0.01 par value per share (“Issuer Common Stock”), of NRG Energy, Inc., a Delaware corporation (the “Issuer”).  The principal executive offices of the Issuer are located at 211 Carnegie Center, Princeton, NJ 08540.

Item 2.

Identity and Background

This statement is being filed jointly by Blackstone TG Capital Partners IV L.P. (“BCP IV”), Blackstone TG Capital Partners IV-B L.P. (“BCP IV-B”), Blackstone Capital Partners IV-A L.P. (“BCP IV-A”), Blackstone Participation Partnership IV L.P. (“BPP”), Blackstone Family Investment Partnership IV-A L.P. (“BFIP”, and together with BCP IV, BCP IV-B, BCP IV-A and BPP, the “Blackstone Funds”), Blackstone Management Associates IV L.L.C. (“BMA”), Peter G. Peterson and Stephen A. Schwarzman (the foregoing, collectively, the “Reporting Persons”).

The principal business of the Blackstone Funds is investing in securities and committing capital to facilitate corporate restructurings, leveraged buyouts, bridge financings and other investments.  The principal business of BMA consists of performing the functions of, and serving as, the general partner of the Blackstone Funds.  The principal business address of each of the Blackstone Funds and BMA is 345 Park Avenue, New York, New York 10154.  Delaware is the jurisdiction of formation for each of the Blackstone Funds and BMA.

Messrs. Peterson and Schwarzman are the founding members (the “Founding Members”) of and control BMA.  Each of the Founding Members is a United States citizen.  The principal occupation of each of the Founding Members is serving as a principal executive officer and director of BMA and the Blackstone Funds.  The business address of the Founding Members is 345 Park Avenue, New York, New York 10154.

During the last five years, none of the Reporting Persons: (i) has been convicted in a criminal proceeding (excluding traffic violations or similar misdemeanors); or (ii) was a party to a civil proceeding of a judicial or administrative body of competent jurisdiction and as a result of such proceeding was or is subject to a judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws or finding any violation with respect to such laws.

Item 3.

Source and Amount of Funds or Other Consideration

As more fully described in Item 4 hereof, on September 30, 2005, the Blackstone Funds entered into an Acquisition Agreement (the “Acquisition Agreement”) with the Issuer, Texas Genco LLC, a Delaware limited liability company (“Texas Genco”) and the other direct and indirect owners of Texas Genco party thereto (together with the Blackstone Funds, the “Sellers”).  Pursuant to the Acquisition Agreement, on February 2, 2006, the Blackstone Funds sold all their ownership interests in Texas Genco (the “Units”) to the Issuer for consideration consisting of cash and shares of Issuer Common Stock.  The transactions contemplated by the Acquisition Agreement did not require the expenditure of any funds by the Reporting Persons to acquire Issuer Common Stock.

Item 4.

Purpose of Transaction

The Acquisition.  On February 2, 2006, pursuant to the Acquisition Agreement, the Issuer acquired all of the outstanding Units (the “Acquisition”), and Texas Genco became a wholly owned subsidiary of the Issuer.  In addition to cash consideration paid to the Sellers and Texas Genco optionholders in connection with the Acquisition, the Issuer issued shares of Issuer Common Stock, including a total of 8,425,761 shares of Issuer Common Stock issued to the Blackstone Funds.

Investor Rights Agreement.  Pursuant to the Acquisition Agreement, on February 2, 2006, the Issuer entered into an Investor Rights Agreement with the Sellers, including the Blackstone Funds, and former Texas Genco optionholders who received Issuer Common Stock in the Acquisition (together with the Sellers, the “Stockholders”).  The Investor Rights Agreement prohibits the Stockholders from selling any of the Issuer Common Stock received in the Acquisition for a period of 180 days after consummation of the Acquisition (the “Lock-up Period”), other than

with the Issuer’s consent and in connection with certain permitted transfers to affiliates.  The agreement also prohibits the Stockholders from entering into any transaction designed to reduce any Stockholder’s risk relative to such Stockholder’s position as a holder of Issuer Common Stock during the Lock-up Period.  Pursuant to the Investor Rights Agreement, the Issuer has agreed to file a shelf registration statement covering resales of Issuer Common Stock issued to the Stockholders in the Acquisition, subject to certain limitations (the “Resale Shelf”) and to cause the Resale Shelf to become effective no later than the expiration of the Lock-up Period.  The Investor Rights Agreement also prohibits the Stockholders from acquiring additional voting securities of the Issuer without the Issuer’s consent, or otherwise attempting to acquire control of the Issuer for a period of two years after the consummation of the Acquisition.

The foregoing summaries of the Acquisition Agreement and Investor Rights Agreement do not purport to be complete and are qualified in their entirety by reference to the complete text of such agreements attached hereto as Exhibit 2 and Exhibit 3, respectively.

The Reporting Persons intend to seek to dispose of their shares of Issuer Common Stock (including, without limitation, distributing some or all of such shares to such Reporting Person’s members, partners, stockholders or beneficiaries, as applicable) from time to time, subject to market conditions, the existence (and possible waiver of) the Lock-up Period and other investment considerations.

In addition to the foregoing, each Reporting Person, subject to the limitations imposed by the Investor Rights Agreement, at any time and from time to time may directly or indirectly acquire additional shares of Issuer Common Stock or its associated rights or securities exercisable for or convertible into Issuer Common Stock, depending upon an ongoing evaluation of its investment in Issuer Common Stock and securities exercisable for or convertible into Issuer Common Stock, applicable legal restrictions, prevailing market conditions, liquidity requirements of such Reporting Person and/or other investment considerations.

Other than as described above, each of the Reporting Persons reports that neither it, nor to its knowledge any of the other persons named in Item 2 of this Schedule 13D, currently has any plan or proposal that relates to, or may result in, any of the matters listed in Items 4(a)–(j) of Schedule 13D, although the Reporting Persons may, at any time and from time to time, review or reconsider their position and/or change their purpose and/or formulate plans or proposals with respect thereto.

Item 5.

Interest in Securities of the Issuer

(a) and (b)  The information contained on the cover pages to this Schedule 13D is incorporated herein by reference.

The Blackstone Funds, acting through their sole general partner BMA, have the sole power to vote or to direct the vote, and to dispose or to direct the disposition of, the Issuer Common Stock respectively owned by them.  As a result, for purposes of section 13(d) of the Act, BMA may be deemed to beneficially own the shares of Issuer Common Stock directly owned by the respective Blackstone Funds of which it is the general partner.  The Founding Members have power to vote or to direct the vote of, and to dispose or to direct the disposition of, the shares of Issuer Common Stock that may be deemed to be beneficially owned by BMA.  As a result, each of the Founding Members may be deemed to beneficially own the shares of Issuer Common Stock that BMA may be deemed to beneficially own.  Each of BMA and each Founding Member disclaims beneficial ownership of such shares.

Neither the filing of this Schedule 13D nor any of its contents shall be deemed to constitute an admission that any Reporting Person or any other person described in Item 2 hereof is the beneficial owner of the Issuer Common Stock referred to herein for purposes of Section 13(d) of the Exchange Act or for any other purpose, and such beneficial ownership is expressly disclaimed.

(c)  Except as set forth in this Item 5, to the best knowledge of each of the Reporting Persons, none of the Reporting Persons has beneficial ownership of, or has engaged in any transaction during the past 60 days in, any shares of Issuer Common Stock.

(d)  Other than the Reporting Persons, no other person has the right to receive or the power to direct the receipt of dividends from, or the proceeds from sale of, the shares of Issuer Common Stock referred to in this Item 5.

(e)  Not applicable.

Item 6.

Contracts, Arrangements, Understandings or Relationships with Respect to Securities of the Issuer

Except as set forth in Item 4 of this Schedule 13D, to the best knowledge of the Reporting Persons, there are no other contracts, arrangements, understandings or relationships (legal or otherwise) among the persons named in Item 2 and between such persons and any other person with respect to any securities of the Issuer, including but not limited to, transfer or voting of any of the securities of the Issuer, finder’s fees, joint ventures, loan or option arrangements, puts or calls, guarantees of profits, division of profits or loss, or the giving or withholding of proxies, or a pledge or contingency the occurrence of which would give another person voting power over the securities of the Issuer.

Item 7.

Material to Be Filed as Exhibits

1.  Joint Filing Agreement, dated February 10, 2006, among Blackstone TG Capital Partners IV L.P., Blackstone Capital Partners IV-A L.P., Blackstone Participation Partnership IV L.P., Blackstone Family Investment Partnership IV-A L.P., Blackstone TG Capital Partners IV-B L.P., Blackstone Management Associates IV L.L.C., Peter G. Peterson and Stephen A. Schwarzman relating to the filing of a joint statement on Schedule 13D (filed herewith).

2.  Acquisition Agreement, dated as of September 30, 2005, among Texas Genco LLC, NRG Energy, Inc. and the direct and indirect owners of Texas Genco LLC party thereto (incorporated by reference to Exhibit 2.1 to NRG Energy, Inc.’s Form 8-K filed October 3, 2005).

3. Investor Rights Agreement, dated as of February 2, 2006, by and among NRG Energy, Inc. and certain stockholders of NRG Energy, Inc. set forth on Annex A thereto (incorporated by reference to Exhibit 10.01 to NRG Energy, Inc.’s Form 8-K filed February 7, 2006).

BLACKSTONE TG CAPITAL PARTNERS IV L.P.

By:

Blackstone Management Associates IV L.L.C., as General Partner

By:

/s/ David Foley

Name:

David Foley

Title:

Member

BLACKSTONE TG CAPITAL PARTNERS IV-B L.P.

By:

Blackstone Management Associates IV L.L.C., as General Partner

By:

/s/ David Foley

Name:

David Foley

Title:

Member

BLACKSTONE CAPITAL PARTNERS IV-A L.P.

By:

Blackstone Management Associates IV L.L.C., as General Partner

By:

/s/ David Foley

Name:

David Foley

Title:

Member

BLACKSTONE PARTICIPATION PARTNERSHIP IV L.P.

By:

Blackstone Management Associates IV L.L.C., as General Partner

By:

/s/ David Foley

Name:

David Foley

Title:

Member

BLACKSTONE FAMILY INVESTMENT PARTNERSHIP IV-A L.P.

By:

Blackstone Management Associates IV L.L.C., as General Partner

By:

/s/ David Foley

Name:

David Foley

Title:

Member

BLACKSTONE MANAGEMENT ASSOCIATES IV L.L.C.

By:

/s/ David Foley

Name:

David Foley

Title:

Member

/s/ Peter G. Peterson

PETER G. PETERSON

/s/ Stephen A. Schwarzman

STEPHEN A. SCHWARZMAN

Dated: February 10, 2006

Exhibit Number

Description of Exhibits

1.

Joint Filing Agreement, dated February 10, 2006, among Blackstone TG Capital Partners IV L.P., Blackstone Capital Partners IV-A L.P., Blackstone Participation Partnership IV L.P., Blackstone Family Investment Partnership IV-A L.P., Blackstone TG Capital Partners IV-B L.P., Blackstone Management Associates IV L.L.C., Peter G. Peterson and Stephen A. Schwarzman relating to the filing of a joint statement on Schedule 13D (filed herewith).

2.

Acquisition Agreement, dated as of September 30, 2005, among Texas Genco LLC, NRG Energy, Inc. and the direct and indirect owners of Texas Genco LLC party thereto (incorporated by reference to Exhibit 2.1 to NRG Energy, Inc.’s Form 8-K filed October 3, 2005).

3.

Investor Rights Agreement, dated as of February 2, 2006, by and among NRG Energy, Inc. and certain stockholders of NRG Energy, Inc. set forth on Annex A thereto (incorporated by reference to Exhibit 10.01 to NRG Energy, Inc.’s Form 8-K filed February 7, 2006).

BLACKSTONE TG CAPITAL PARTNERS IV L.P.

By:  Blackstone Management Associates IV L.L.C., as General
Partner

By:

/s/ David Foley

Name:

David Foley

Title:

Member

BLACKSTONE TG CAPITAL PARTNERS IV-B L.P.

By:  Blackstone Management Associates IV L.L.C., as General
Partner

By:

/s/ David Foley

Name:

David Foley

Title:

Member

BLACKSTONE CAPITAL PARTNERS IV-A L.P.

By:  Blackstone Management Associates IV L.L.C., as General
Partner

By:

/s/ David Foley

Name:

David Foley

Title:

Member

BLACKSTONE PARTICIPATION PARTNERSHIP IV L.P.

By:  Blackstone Management Associates IV L.L.C., as General
Partner

By:

/s/ David Foley

Name:

David Foley

Title:

Member

BLACKSTONE FAMILY INVESTMENT PARTNERSHIP IV-
A L.P.

By:  Blackstone Management Associates IV L.L.C., as General Partner

By:

/s/ David Foley

Name:

David Foley

Title:

Member

BLACKSTONE MANAGEMENT ASSOCIATES IV L.L.C.

By:

/s/ David Foley

Name:

David Foley

Title:

Member

/s/ Peter G. Peterson

PETER G. PETERSON

/s/ Stephen A. Schwarzman

STEPHEN A. SCHWARZMAN