Electric power sector generation from renewable sources totaled 795 million megawatthours (MWh) in the United States during 2021, surpassing nuclear generation, which totaled 778 million MWh. The U.S. electric power sector does not include electricity generators in the industrial, commercial, or residential sectors, such as small-scale solar or wind or some combined-heat-and-power systems. Renewable generation includes electricity generated from wind, hydropower, solar, biomass, and geothermal sources.

Natural gas remained the most prevalent source of energy used in electricity generation in the United States, accounting for 1,474 million MWh in 2021. Although several U.S. coal-fired power plants retired in 2021, coal-fired electricity generation increased for the first time since 2014 and was the source of more U.S. electricity than either renewables or nuclear power. Total generation in the electric power sector increased slightly in 2021, but it remained less than its record-high year of 2018.

The increase in U.S. electric power sector renewable generation during 2021 came mainly from more wind and solar generation as a result of more wind turbines and utility-scale solar power plants coming online. Wind generation increased by 12% in 2021, and utility-scale solar generation increased by 28%. Hydroelectric generation decreased to its lowest level since 2015, mainly because of dry conditions in the western United States. Biomass and geothermal electricity generation remained relatively unchanged in 2021.

Nuclear-powered generation has remained relatively steady in the United States during the past decade because uprates at existing facilities have offset the retirement of several reactors. Only one reactor was retired in 2021: New York’s Indian Point Unit 3. Despite a slight increase in the capacity factor of the U.S. nuclear fleet in 2021, U.S. nuclear electricity generation fell to its lowest level since 2012.