U.S. State Greenhouse Gas Emissions Standards for Power Plants
In 2016, the electricity sector was the second-largest source of U.S. greenhouse gas emissions. Electricity-related emissions are primarily the result of combusting fossil fuels in power plants. Coal-fired power plants accounted for nearly 70 percent of greenhouse gas emission from the electricity sector, but emissions from natural gas plants are rising substantially.
Individual power plants have a wide range of emission rates, stemming from differences in the type of fossil fuel used (generally coal or natural gas) and the efficiency of the plant. Modifying coal plants to burn natural gas is one way to reduce emission rates. Carbon capture, utilization, and storage (CCUS) is another option to reduce power plant emissions.
The objective of a carbon dioxide performance standard is to reduce power plant emissions. Some standards set absolute limits on the emissions from the entire sector, as is done in cap and trade programs. Other states set intensity limits (e.g., pounds of carbon dioxide per megawatt-hour) on individual power plants or require emission-reducing technology like CCUS. These standards reduce emissions on a relative basis, but could still allow an increase in total sector emissions. Designated sources might include only new plants, only existing plants, or both.