Glossary

Primary energy

Primary energy:  Energy in the form that it is first accounted for in a statistical energy balance, before any transformation to secondary or tertiary forms of energy. For example, coal can be converted to synthetic gas, which can be converted to electricity; in this example, coal is primary energy, synthetic gas is secondary energy, and electricity is tertiary energy. See Primary energy production and Primary energy consumption.

Primary energy consumption:  Primary energy consumption: Consumption of primary energy. The U.S. Energy Information Administration includes the following in U.S. primary energy consumption:

Coal consumption

Coal coke net imports

Petroleum consumption (equal to petroleum products supplied, excluding biofuels)

Dry natural gas, excluding supplemental gaseous fuels

Nuclear electricity net generation (converted to Btu using the average annual heat rate of nuclear plants)

Conventional hydroelectricity net generation (converted to Btu using the heat content of electricity)

Geothermal electricity net generation (converted to Btu using the heat content of electricity), geothermal heat pump energy and geothermal direct-use thermal energy

Solar thermal and photovoltaic electricity net generation, both utility-scale and small-scale (converted to Btu using the heat content of electricity)

Solar thermal direct-use energy

Wind electricity net generation (converted to Btu using the heat content of electricity)

Wood and wood-derived fuels consumption

Biomass waste consumption

Biofuels (fuel ethanol, biodiesel, renewable diesel fuel, and other biofuels) consumption

Losses and co-products from the production of fuel ethanol and biodiesel

Electricity net imports (converted to Btu using the heat content of electricity)

Primary energy consumption also includes all non-combustion uses of fossil fuels. Energy sources produced from other energy sources—for example, coal coke from coal—are included in primary energy consumption only if their energy content has not already been included as part of the original energy source. As a result, U.S. primary energy consumption does include net imports of coal coke, but it does not include the coal coke produced from domestic coal.

Note: In some EIA publications, conventional hydroelectricity net generation, geothermal electricity net generation, solar thermal and photovoltaic electricity net generation (both utility-scale and small-scale), and wind electricity net generation are converted to Btu using the average annual heat rate of fossil-fueled plants, under definitions used prior to September 2023.

Primary energy consumption expenditures:  Expenditures for energy consumed in each of the four major end-use sectors, excluding energy in the form of electricity, plus expenditures by the electric utilities sector for energy used to generate electricity. There are no fuel-associated expenditures for associated expenditures for hydroelectric power, geothermal energy, photovoltaic and solar energy, or wind energy. Also excluded are the quantifiable consumption expenditures that are an integral part of process fuel consumption.

Primary energy production:  Production of primary energy. The U.S. Energy Information Administration includes the following in U.S. primary energy production:

Coal production, waste coal supplied, and coal refuse recovery

Crude oil and lease condensate production

Natural gas plant liquids production

Dry natural gas excluding supplemental gaseous fuels production

Nuclear electricity net generation (converted to Btu using the nuclear plant heat rates)

Conventional hydroelectricity net generation (converted to Btu using the heat content of electricity)

Geothermal electricity net generation (converted to Btu using the heat content of electricity), and geothermal heat pump energy and geothermal direct use energy

Solar thermal and photovoltaic electricity net generation (converted to Btu using the heat content of electricity), and solar thermal direct use energy

Wind electricity net generation (converted to Btu using the heat content of electricity)

Wood and wood-derived fuels production

Biomass waste consumption

Fuel ethanol and biodiesel feedstock and renewable diesel and other biofuels production

Note: In some EIA publications, conventional hydroelectricity net generation, geothermal electricity net generation, solar thermal and photovoltaic electricity net generation (both utility-scale and small-scale), and wind electricity net generation are converted to Btu using the average annual heat rate of fossil-fueled plants, under definitions used prior to September 2023.