Major Sources of Energy in the United States | EBF 301

“Non-renewable” energy sources (such as Oil and Petroleum Products, Natural Gas, Natural Gas Liquid, Coal, and Nuclear), as well as “renewable” energy and “alternative fuels” (such as Hydro, Solar, Wind, Geothermal, Biomass, and Biofuels), help to satisfy the nation’s energy needs. Fossil fuels and nuclear power are considered non-renewable sources of energy. Coal and natural gas play large roles in the generation of electricity as well as in industrial processes such as the manufacturing of steel. Hydro, solar, wind, biomass, biofuels, and geothermal are all considered “renewable” forms of energy and comprise varying levels of supply in this country. They are classified as renewables since their source is seen as being virtually unlimited. Of these, solar, wind, biomass, biodiesel, and geothermal are all considered “alternative” energy sources since they are not the “traditional” kind (fossil fuels, nuclear, and hydro).

The following chart is from EIA reported data and shows major energy sources and percent shares of U.S. electricity generation at utility-scale facilities in 2021. Please note that in 2021 natural gas has the largest share (38%) in U.S. electricity generation, coal is in the second place (22%), and nuclear has the third place (19%). As shown in Figure 1, renewable energy sources contribute to about 20% of the U.S. electricity production at utility-scale facilities as of 2021, with about 9.2% wind power and 6.3% hydro. Please note that 2019 was the first year that wind power surpass the hydro. Other renewable sources such as solar, biomass and geothermal have a minor share.

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U.S. Electricity Generation in 2019

Total = 4.009 trillion kilowatthours (kWh)

• Natural Gas: 40%

• Nuclear: 20%

• Coal: 19%

• Renewables: 20%

The renewables are broken down as follows:

• Wind: 8.4%

• Hydropower: 7.3%

• Solar: 2.3%

• Biomass: 1.4%

• Geothermal: 0.4%

Figure 1: Major energy sources and percent shares of U.S. electricity generation at utility-scale facilities in 2020

Source of data: EIA, What is U.S. electricity generation by energy source

Figure 2 below shows the break-out of fuel sources used in the generation of electricity. As you can see, the single largest fuel has been coal in the past decades, although this is changing as historically low natural gas prices during 2010-2020 caused some “fuel switching.” This was followed by natural gas, nuclear, and renewable energy sources. This final category is comprised of energy sources such as wind, solar, hydroelectric, biomass, and geothermal.

Figure 2: U.S. Electricity Generation by Source

Source: EIA 2020

Figure 3, below, displays the renewable energy sources that contribute to power generation. As you can see, there has been a rapid increase in wind and solar power generation. However, it will take decades for alternative fuels to make a substantial contribution to the energy portfolio in the United States. Thus, there is a need to continue to use fossil fuels and nuclear power to “bridge” the gap. How the former (fossil fuels and nuclear power) are delivered to market and how they are priced is the main focus of this course.

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Renewable electricity generation

1950 - 2020 (history) 

Geothermal: Geothermal generation was relatively stable, and very low, from 1990 - 2020. 

Biomass: Biomass generation has remained steady at about 50 - 60 billion kWh from 1990 - 2020.

Hydroelectric: Hydroelectric generation varied widely between about 220 billion kWh and 350 billion kWh from 1990 - 2021. 

Utility-scale and end-use solar: Solar generated almost zero kWh before 2010. It rose from almost zero to about 115 billion kWh by 2021.

Wind: Wind power generated almost no power until 2004. From 2004 until 2021 it rose to about 378 billion kWh, more than 25 times of 2004 generation level. 

Figure 3: Renewable electricity generation

Source: EIA 2020

• Geothermal: Geothermal generation was relatively stable, and very low, from 1990 - 2020. 
• Biomass: Biomass generation has remained steady at about 50 - 60 billion kWh from 1990 - 2020.
• Hydroelectric: Hydroelectric generation widely between about 220 billion kWh and 350 billion kWh from 1990 - 2021. 
• Solar: Utility-scale and end-use solar generated almost zero kWh before 2010. It rose from almost zero to about 115 billion kWh by 2021.
• Wind: Wind power generated almost no power until 2004. From 2004 until 2021 it rose to about 378 billion kWh, more than 25 times of 2004 generation level.

Now that we have clarified the difference between renewable and non-renewable sources of energy, let’s have a look at the production and consumption of energy in the United States on a macro level.

Electricity in the United States is produced (generated) with 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 sources. Most electricity is generated with steam turbines using fossil fuels, nuclear, biomass, geothermal, and solar thermal energy. Other major electricity generation technologies include gas turbines, hydro 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 electric generation capacity. Small-scale systems have less than 1 MW (1,000 kilowatts) of electric generation capacity. In 2022, total U.S. utility-scale electricity generation was about 4.24 trillion kilowatthours (kWh). EIA estimates that about 0.06 trillion kWh of electricity were generated with small-scale solar photovoltaic systems.

Fossil fuels are the largest sources of energy for electricity generation

Natural gas was the largest source—about 40%—of U.S. electricity generation in 2022. Natural gas is used in steam turbines and gas turbines to generate electricity.

Coal was the third-largest energy source for U.S. electricity generation in 2022—about 18%. Nearly all coal-fired power plants use steam turbines. A few coal-fired power plants convert coal to a gas for use in a gas turbine to generate electricity.

Petroleum was the source of less than 1% of U.S. electricity generation in 2022. Residual fuel oil and petroleum coke are used in steam turbines. Distillate—or diesel—fuel oil is used in diesel-engine generators. Residual fuel oil and distillates can also be burned in steam and gas turbines.

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

Nuclear energy was the source of about 18% of U.S. electricity generation in 2022. Nuclear power plants use steam turbines to produce electricity from nuclear fission.

Renewable energy sources provide an increasing share of U.S. electricity

Many renewable energy sources are used to generate electricity and were the source of about 22% of total U.S. electricity generation in 2022. In 1990, renewable resources provided about 12% of utility-scale electricity generation.

Wind energy was the source of about 10.2% of total U.S. utility-scale electricity generation and accounted for 47.6% of electricity generation from renewable sources in 2022. Wind turbines convert wind energy into electricity.

Hydropower plants produced about 6.2% of total U.S. utility-scale electricity generation and accounted for 28.7% of electricity generation from renewable sources in 2022.1 Hydropower plants use flowing water to spin a turbine connected to a generator.

Solar energy provided about 3.4% of total U.S. utility-scale electricity and accounted for 15.9% of utility-scale electricity generation from renewable sources in 2022. Photovoltaic (PV) and solar-thermal power are the two main types of solar electricity generation technologies. 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 0.06 trillion kWh of electricity were generated with small-scale solar photovoltaic systems.

Biomass was the source of about 1.3% of total U.S. utility-scale electricity generation and accounted for 5.9% of electricity generation from renewable sources in 2022. 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.

Geothermal power plants produced about 0.4% of total U.S. utility-scale electricity generation and accounted for 1.9% of electricity generation from renewable sources in 2022. Geothermal power plants use steam turbines to generate electricity.

Last updated: June 30, 2023, with data from the Electric Power Monthly, February 2023; data for 2022 are preliminary.