Ownership Submission
FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
FLEXON ROBERT C
  2. Issuer Name and Ticker or Trading Symbol
NRG ENERGY, INC. [NRG]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
Executive VP and COO
(Last)
(First)
(Middle)
NRG ENERGY, INC., 211 CARNEGIE CENTER
3. Date of Earliest Transaction (Month/Day/Year)
04/22/2008
(Street)

PRINCETON, NJ 08540
4. If Amendment, Date Original Filed(Month/Day/Year)
6. Individual or Joint/Group Filing(Check Applicable Line)
_X_ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security
(Instr. 3)
2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code
(Instr. 8)
4. Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5)
5. Amount of Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 3 and 4)
6. Ownership Form: Direct (D) or Indirect (I)
(Instr. 4)
7. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V Amount (A) or (D) Price
Common Stock, par value .01 per share 04/22/2008   M(1)   100,000 A $ 10.925 196,624 D  
Common Stock, par value .01 per share 04/22/2008   S(1)   100,000 D $ 45 96,624 D  

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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 3)
2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code
(Instr. 8)
5. Number of Derivative Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4, and 5)
6. Date Exercisable and Expiration Date
(Month/Day/Year)
7. Title and Amount of Underlying Securities
(Instr. 3 and 4)
8. Price of Derivative Security
(Instr. 5)
9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 4)
10. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 4)
11. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares
Non-Qualifed Stock Option $ 10.925 04/22/2008   M(1)     100,000 03/29/2005(2) 03/29/2015 Common Stock, par value $.01 per share 100,000 $ 0 90,000 D  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
FLEXON ROBERT C
NRG ENERGY, INC.
211 CARNEGIE CENTER
PRINCETON, NJ 08540
      Executive VP and COO  

Signatures

 /s/ Brian Curci, under Power of Attorney   04/24/2008
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) The exercise and sale reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by Mr. Flexon on August 31, 2007.
(2) Pursuant to the Grant Agreement by and between NRG Energy, Inc. and Mr. Flexon, the Non-Qualified Stock Options vested and became exercisable as follows: 33 1/3% on March 29, 2005, 33 1/3% on March 29, 2006 and 33 1/3% on March 29, 2007.

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