GenOn Energy Holdings
![Mirant's Morgantown Generating Station and the Governor Harry W. Nice Memorial Bridge](/Images/godic/202501/27/Harrynicebridge6030601.jpg")
![Unit 3 of Mirant's Potrero Generating Station in San Francisco.](/Images/godic/202501/27/Unit_3_-_Potrero_Power_Plant0601.jpg")
GenOn Energy Holdings, formerly Mirant Corporation, was a subsidiary of GenOn Energy, and is now a part of NRG Energy.
The company was spun off from its former parent, Southern Company, on April 2, 2001. The company was merged into GenOn Energy on 3 December 2010. The company then became part of NRG Energy in December 2012.