Astoria Gas Turbine Power S-4 Registration of securities issued in business combination transactions

Exhibit 3.127

State of Delaware

Secretary of State

Division of Corporations

Delivered 12:23 PM 03/11/2015

FILED 12:16 PM 03/11/2015

SRV 150341520 - 5707747 FILE

CERTIFICATE OF FORMATION

OF

NRG BUSINESS SERVICES LLC

1.             Name: The name of the limited liability company is NRG Business Services LLC.

2.             Registered Office: The address of its registered office in the State of Delaware is Corporation Trust Center, 1209 Orange Street, in the City of Wilmington 19801, County of New Castle. The name of its registered agent at such address is The Corporation Trust Company.

3.             Organizer: The name and address of the sole organizer of the limited liability company is Elizabeth McCormack, NRG Energy, Inc., 211 Carnegie Center, Princeton, NJ 08540.

IN WITNESS WHEREOF, the undersigned has executed this Certificate of Formation of NRG Business Services LLC this 11th day of March, 2015.

/s/ Elizabeth McCormack

Elizabeth McCormack

Authorized Person