GenOn Energy, Inc. operates as a generator of wholesale electricity in the United States. Its portfolio of power generation facilities include baseload, intermediate, and peaking units using coal, natural gas, and oil to generate electricity. The company owns, contracts, or operates approximately 49 power generation stations with generation capacity of 24,599 megawatts. The company was formerly known as Mirant Corporation and changed its name to GenOn Energy, Inc. on December 4, 2010. The company is based in Houston, Texas.