CO₂ emissions from top power producers in the U.S. 2021, by fuel source
The most polluting power producer in the United States in 2021 was Vistra Energy, having emitted 110 million tons of carbon dioxide (MTCO₂). Coal-fired plants accounted for roughly 63 percent of Vistra Energy's CO₂ emissions that year, while natural gas accounted for 36 percent. Coal is the most polluting of fossil fuel, typically producing twice the carbon emissions of natural gas when combusted.