Electricity in the US is generated from several diverse energy sources and technologies.

The United States uses many different energy sources and technologies to generate electricity. The sources and technologies have changed over time, and some are used more than others.

The three major categories of energy for electricity generation are fossil fuels (coal, natural gas, and petroleum), nuclear energy, and renewable energy. Most electricity is generated with steam turbines that use fossil fuels, nuclear, biomass, geothermal, or solar thermal energy. Other major electricity generation technologies include gas turbines, hydro (water) turbines, wind turbines, and solar photovoltaics.

The U.S. Energy Information Administration publishes data on electricity generation from utility-scale and small-scale systems. Utility-scale systems include power plants that have at least 1 megawatt (MW) of electricity generation capacity. Small-scale systems have less than 1 MW (1,000 kilowatts) of electric generation capacity. In 2023, total U.S. utility-scale electricity generation was about 4.18 trillion kilowatt-hours (kWh). EIA estimates that about 0.07 trillion kWh of electricity were generated with small-scale solar photovoltaic systems.

Fossil fuels account for about 60% of U.S. electricity that was generated in 2023

Natural gas was the top source—about 43%—of U.S. utility-scale electricity generation in 2023. Natural gas is used in steam turbines and gas turbines to generate electricity.

Coal was the fourth-highest energy source—about 16%—of U.S. electricity generation in 2023. Nearly all coal-fired power plants use steam turbines. One power plant converts coal to a gas to use in gas turbines to generate electricity.

Petroleum was the source of about 0.4% of U.S. electricity generation in 2023. Residual fuel oil and petroleum coke are used in steam turbines. Distillate—or diesel—fuel oil is used in internal-combustion engines such as diesel-engine generators. Residual fuel oil and distillates can also be burned in steam turbines and gas turbines.

Other gases and other sources accounted for about 0.5% of U.S. utility-scale electricity generation in 2023. Other gases include blast furnace gas and other manufactured and waste gases derived from fossil fuels. Other sources include pumped-storage hydroelectric, non-biogenic municipal solid waste, batteries, hydrogen, purchased steam, sulfur, tire-derived fuel, and other miscellaneous energy sources.

Nuclear energy provides nearly one-fifth of U.S. electricity

Nuclear energy was the third-highest source—about 18%—of U.S. utility-scale electricity generation in 2023. Nuclear power plants use steam turbines to produce electricity from nuclear fission.

Renewable energy provides an increasing share of U.S. electricity

Many different renewable energy sources are used to generate electricity, and they were the source of about 21% of total U.S. utility-scale electricity generation in 2023. In 1990, renewable resources provided about 12% of utility-scale electricity generation.

Wind energy was the source of about 10% of total U.S. utility-scale electricity generation and accounted for 48% of the electricity generation from renewable sources in 2023. Wind turbines convert wind energy into electricity.

Hydropower (conventional) plants produced about 6% of total U.S. utility-scale electricity generation and accounted for about 27% of utility-scale electricity generation from renewable sources in 2023. Hydropower plants use flowing water to spin a turbine connected to a generator.

Solar photovoltaic and solar thermal power plants provided about 4% of total U.S. utility-scale electricity and accounted for 18% of utility-scale electricity generation from renewable sources in 2023. Nearly all solar electric generation was from photovoltaic systems (PV). PV conversion produces electricity directly from sunlight in a photovoltaic cell. Most solar-thermal power systems use steam turbines to generate electricity. EIA estimates that about 0.07 trillion kWh of electricity were generated with small-scale solar photovoltaic systems.

Biomass…a renewable energy source, but not so clean

Organic matter such as wood, crops, food waste and animal manure that is turned into fuel via direct burning or chemical conversion is called Biomass.

Biomass was the source of about 1% of total U.S. utility-scale electricity generation and accounted for 5% of the utility-scale electricity generation from renewable sources in 2023. Biomass is burned directly in steam-electric power plants, or it can be converted to a gas that can be burned in steam generators, gas turbines, or internal combustion engine generators.

While biomass itself is a renewable resource, biomass plants can actually emit concerning levels of CO2 and other greenhouse gasses into the air when burning. So, critics claim that biomass isn’t yet a truly clean energy source.

Biomass energy sources include:

• Wood: This includes firewood, wood chips and pellets, and waste products and sawdust from furniture and lumber mills.
• Crops: Corn and soybeans as mentioned, along with switchgrass, sugar cane, woody plants, algae, and waste from food and crop processing facilities.
• Biogenic materials: Certain solid waste products count as biomass, such as cotton and wool products, paper, food, and yard and wood wastes.
• Animal manure and human sewage: No further explanation needed

Geothermal Power

Geothermal power plants produced less than 1% of total U.S. utility-scale electricity generation and accounted for about 2% of the utility-scale electricity generation from renewable sources in 2023. Geothermal power plants use steam turbines to generate electricity.

Geothermal energy is thermal energy extracted from the Earth’s crust. It combines energy from the formation of the planet and from radioactive decay. Geothermal energy has been exploited as a source of heat and/or electric power for millennia.

Geothermal electricity generation is currently used in 26 countries, while geothermal heating is in use in 70 countries. As of 2019, worldwide geothermal power capacity amounts to 15.4 gigawatts (GW), of which 23.9% (3.68 GW) are installed in the United States.

Geothermal power is considered to be a sustainable, renewable source of energy because the heat extraction is small compared with the Earth’s heat content. The greenhouse gas emissions of geothermal electric stations average 45 grams of carbon dioxide per kilowatt-hour of electricity, or less than 5% of those of conventional coal-fired plants.

As a source of renewable energy for both power and heating, geothermal has the potential to meet 3 to 5% of global demand by 2050. With economic incentives, it is estimated that by 2100 it will be possible to meet 10% of global demand with geothermal power.

Final thought

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Last updated 3.2024 from the US Energy Information Administration site: 

Electricity in the U.S. – U.S. Energy Information Administration (EIA)