In 2021, total annual U.S. electricity net generation by utility-scale electric power plants (plants with at least one megawatt of electric generation capacity) of about 4.11 trillion kilowatthours (kWh) from all energy sources resulted in the emission of about 1.65 billion metric tons—1.82 billion short tons—of carbon dioxide (CO2). This equaled about 0.855 pounds of CO2 emissions per kWh.
Emissions from electricity generation vary by type of fuel/energy source and by type and efficiency of electric power plants. The amount of CO2 produced per kWh during any period of time will vary according to the sources of electricity supplied to the electric power grid during that time. Therefore, electricity-related CO2 emissions and CO2 emission factors will vary hourly, daily, monthly, and annually. The U.S. Energy Information Administration (EIA) publishes CO2 emissions estimates related to electricity generation on a monthly and annual basis.
In 2021, utility-scale electric power plants that burned coal, natural gas, and petroleum fuels were the source of about 61% of total annual U.S. utility-scale electricity net generation, but they accounted for 99% of U.S. CO2 emissions associated with utility-scale electric power generation. The other 1% of CO2 emissions were from other fuels and gases derived from fossil fuels and some types of geothermal power plants. EIA considers electricity generation from biomass, hydro, solar, and wind to be carbon neutral.
The table below presents data on total annual electricity net generation and CO2 emissions at utility-scale electric power plants and a CO2 emission factor (pounds of CO2/kWh) for coal, natural gas, and petroleum. Actual CO2 emissions per KWh from specific power plants may vary considerably from the factors in the table.
|Electricity generation||CO2 emissions|
|million kWh||million metric tons||million short tons||pounds per kWh|
|Data source: U.S. Energy Information Administration, State Electricity Profiles, U.S. Profile.|
Note: Data are for utility-scale electric power plants, including combined heat and power plants.
State-level emissions and emissions factors
EIA publishes annual CO2 emissions and average annual CO2 emissions factors related to total electricity generation by the electric power industry in the United States and in each state in the State Electricity Profiles. In each profile, Table 1 has the CO2 emissions and emission factor for the most recent year available, and Table 7 has historical annual emissions and emissions factors back to 1990. To find Table 7, see the link under Table 1 for Full data tables 1-17. The factors are in pounds of CO2 per megawatthour (MWh). Divide the factors by 1,000 to convert the factor to pounds per kWh.
State-level emissions and electricity generation by type of fuel
There are more state-level data on electricity-related CO2 emissions and electricity generation by type of electricity producer and by fuel/energy source in state-level electricity data files (xls).
How much coal, natural gas, or petroleum is used to generate a kilowatthour of electricity?
What are the greenhouse gas and air pollutant emissions factors for fuels and electricity?
What is the efficiency of different types of power plants?
Does EIA have data on each power plant in the United States?
Where greenhouse gases come from
Last updated November 25, 2022, with most recent data available at the time of update.