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Frequently Asked Questions

How much coal, natural gas, or petroleum is used to generate a kilowatthour of electricity?

The amount of fuel used to generate electricity depends on the efficiency or heat rate of the generator (or power plant) and the heat content of the fuel. Power plant efficiencies (heat rates) vary by types of generators (prime movers), power plant emission controls, and other factors. The heat content of different fuels also varies.

Two formulas can be used to calculate the amount of fuel used to generate a kilowatthour (kWh) of electricity:

  • Amount of fuel used per kWh = Heat rate (in British Thermal Units (Btu) per kWh) divided by Fuel heat content (in Btu per physical unit)
  • Kilowatthour generated per unit of fuel used = Fuel heat content (in Btu per physical unit) divided by Heat rate (in Btu per kWh)

Data sources for the calculations:

Electric Power Annual

Monthly Energy Review, Appendices with fuel heat contents, electricity heat rates, and conversion factors

You can calculate the average amounts of fuels used to generate electricity in the United States, in each state, and at individual power plants using

Last reviewed: March 8, 2019

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