Vistra Corp. is an integrated retail electricity and power generation company based in Irving, Texas. The company is the largest competitive power generator in the U.S. with a capacity of approximately 39GW powered by a diverse portfolio, including natural gas, coal, nuclear, solar, and battery energy storage facilities. In the 2020 Forbes Global 2000, Vistra Energy was ranked as the 756th-largest public company in the world. The company owns the Moss Landing Power Plant in California which as of 2021 contained the largest battery energy storage system in the world, but was significantly damaged in a fire in January 2025. As of 2020, the company was ranked as the highest CO₂ emitter in the US. In 2024, it is ranked first as the No. 1 polluter in the United States for the 2024 Greenhouse 100 Polluters Index Report, producing 1.5% of all greenhouse gas emissions generated in the United States of America, according to the Political Economy Research Institute at the University of Massachusetts, Amherst.