Utility-scale electricity generation plants in the United States consumed nearly 39 quadrillion British thermal units (quads) of energy to provide 13 quads of electricity for end-use consumption in 2018, according to the U.S. Energy Information Administration (EIA). A total of 101 quads of primary energy was consumed in 2018, and U.S. electricity generation comprised more than 38% of total end-use consumption.
Electricity is a secondary energy source that’s produced when energy sources such as coal, natural gas, nuclear and renewable energy are converted into electric power, according to the EIA. Total energy lost during the conversion process was 23.8 quads, or 61% of total consumption, in 2018.
Power plant efficiency is affected by technology and the type of fuel used to generate electricity. Coal accounted for 31% of energy consumption, or 12 quads, and it produced 27% of the electricity generated, or 3.9 quads. Natural gas accounted for 29% of energy consumption, or 11.2 quads, and it produced 35% of the electricity generated, or 5 quads. U.S. coal-fired plants generate electricity less efficiently than natural gas plants in the United States, according to the EIA. Coal-fired plants require about one-third more British thermal units of energy to generate a kilowatt-hour of electricity than natural gas plants.
Over the past several decades, the fuel mix of the U.S. electric power grid has shifted from mostly coal to a combination of fuels, including natural gas, nuclear and renewable energy. The shift to more efficient natural gas plants with combined-cycle generators has led to a rise in the average efficiency of fossil fuel-fired electric power plants and a decline in the overall losses related to energy conversion.
Nearly all of the 13.5 quads of electricity used in the United States in 2018 was delivered as retail sales to the four end-use sectors: residential, commercial, industrial and transportation. The remaining 4% was self-generated electricity for direct use by facilities in the commercial and industrial sectors. The residential and commercial sectors consumed almost 75% of electricity sold at retail. The industrial sector consumed 25% of electricity sold at retail. The transportation sector used 0.03 quads, the smallest amount of electricity consumed in 2018.