Electricity Energy Information Administration (EIA) Frequently Asked Questions

Energy Information Administration (EIA) Frequently Asked Questions about Electricity

n 2013, the United States generated about 4,058 billion kilowatthours of electricity.  About 67% of the electricity generated was from fossil fuel (coal, natural gas, and petroleum), with 39% attributed from coal.

In 2013, energy sources and percent share of total electricity generation were

  • Coal 39%
  • Natural Gas 27%
  • Nuclear 19%
  • Hydropower 7%
  • Other Renewable 6%
    • Biomass 1.48%
    • Geothermal 0.41%
    • Solar 0.23%
    • Wind 4.13%
  • Petroleum 1%
  • Other Gases < 1%

Does EIA have data on each power plant in the United States?

Other FAQs about Electricity

Data on existing individual electric generators at U.S. power plants, including the operational status, generating capacity, primary fuel/energy sources used, type of prime mover, location, the month and year of initial operation, and other information are collected with the EIA-860 survey.   Summary data on all generators are available in worksheets by the primary fuel/energy source used by the generators. Monthly and total annual fuel consumption, power generation, and various environmental data for power plants are collected with the EIA-923 survey.



EIA has an interactive map that includes the location of power plants and major electric power transmission lines in the United States.  To learn more about this map, play a short instructional video on how to use the EIA State Energy Portal tool. EIA currently does not  publish any other information on the location of power lines. The address of power plants with 1 MW or greater in generation capacity are in the “PlantYyy” file of the EIA-860 database



EIA estimates that the U.S. residential sector consumed about 1,375 billion kilowatthours of electricity in 2012. Estimated U.S. Residential Electricity Consumption by End Use, 2012

End Use Quadrillion
Share of
Space cooling 0.85 250 18%
Lighting 0.64 186 14%
Water heating 0.45 130 9%
Refrigeration 0.38 111 8%
Televisions and related equipment 1 0.33 98 7%
Space heating 0.29 84 6%
Clothes dryers 0.20 59 4%
Computers and related equipment2 0.12 37 3%
Cooking 0.11 31 2%
Dishwashers3 0.10 29 2%
Furnace fans and boiler circulation pumps 0.09 28 2%
Freezers 0.08 24 2%
Clothes washers3 0.03 9 1%
Other uses4 1.02 299 22%
Total consumption 4.69 1,375  

1 Includes televisions, set-top boxes, home theater systems, DVD players, and video game consoles. 2 Includes desktop and laptop computers, monitors, and networking equipment. 3 Does not include water heating portion of load. 4 Includes small electric devices, heating elements, and motors not listed above. Electric vehicles are included in the transportation sector.

There are about 19,023 individual generators at about 6,997 operational power plants in the United States with a nameplate generation capacity of at least one megawatt. A power plant can have one or more generators, and some generators may use more than one type of fuel. Learn more: Electric Power Annual 2012, Table 4.1: Count of Electric Power Industry Power Plants, by Sector, by Predominant Energy Sources within Plant (some plants are double-counted by fuel type in Table 4.1), and Table 4.3: Existing Capacity by Energy Source. Downloadable databases with detailed data on individual generators and power plants.

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, power plant emission controls, and other factors. Fuel heat contents also vary.

Two formulas for calculating the amount of fuel used to generate a kilowatthour (kWh) of electricity:

  • Amount of fuel used per kWh = Heat rate (in Btu per kWh) / Fuel heat content (in Btu per physical unit)
  • Kilowatthour generated per unit of fuel used = Fuel heat content (in Btu per physical unit) / Heat rate (in Btu per kWh)

Calculation examples using these two formulas and the assumptions below:

  • Amount of fuel used to generate one kilowatthour (kWh):
    • Coal = 0.00054 short tons or 1.09 pounds
    • Natural gas = 0.00786 Mcf (1,000 cubic feet)
    • Petroleum = 0.00188 barrels (or 0.08 gallons)
  • Kilowatthour generated per unit of fuel used:
    • 1,842 kWh per ton of Coal or 0.9 kWh per pound of Coal
    • 127 kWh per Mcf (1,000 cubic feet) of Natural gas
    • 533 kWh per barrel of Petroleum, or 12.7 kWh per gallon

Assumptions: Power plant heat rate

  • Coal = 10,498 Btu/kWh
  • Natural gas = 8,039 Btu/kWh
  • Petroleum = 10,991 Btu/kWh

Fuel heat contents

  • Coal = 19,336,000 Btu per short ton (2,000 lbs) Note: heat contents of coal vary widely by types of coal.
  • Natural gas  = 1,023,000 Btu per 1,000 Cubic Feet (Mcf)
  • Petroleum = 5,861,814 Btu per Barrel (42 gallons) Note: Heat contents vary by type of petroleum product.

EIA publishes estimates for the capital costs for different types of electricity generators in the Updated Capital Cost Estimates for Electricity Generation Plants report.

EIA estimates that national electricity transmission and distribution losses average about 6% of the electricity that is transmitted and distributed in the United States each year

Capacity factor is a measure of how often an electric generator runs for a specific period of time. It indicates how much electricity a generator actually produces relative to the maximum it could produce at continuous full power operation during the same period.

Over the past 6 years, the average capacity factors were: Coal 64%, Natural Gas combined cycle 44%, Nuclear 90%, Hydropower 40%, Wind 31%, Solar PV 20%, Solar Thermal 22%, Geothermal 71%

Capacity is the maximum electric output a generator can produce under specific conditions. Nameplate capacity is determined by the generator’s manufacturer and indicates the maximum output a generator can produce without exceeding design thermal limits.

Net summer capacity and net winter capacity are typically determined by a performance test and indicate the maximum load a generator can support at the point of interconnection during the respective season. The primary factors that affect or determine the difference in capacity between summer and winter months are:

  • the temperature of cooling water for thermal power plants or of the ambient air for combustion turbines
  • the water flow and reservoir storage characteristics for hydropower plants

Generation is the amount of electricity a generator produces over a specific period of time. For example, a generator with 1 megawatt (mW) capacity that operates at that capacity consistently for one hour will produce 1 megawatthour (mWh) of electricity. If it operates at only half that capacity for one hour, it will produce 0.5 mWh of electricity. Many generators do not operate at their full capacity all the time; they may vary their output according to conditions at the power plant, fuel costs, and/or as instructed from the electric power grid operator.

Net generation is the amount of gross generation a generator produces less the electricity used to operate the power plant.  These uses include fuel handling, feedwater pumps, combustion air fans, cooling water pumps, pollution control equipment, and other electricity needs.

One measure of the efficiency of a power plant that converts a fuel into heat and into electricity is the heat rate. The heat rate is the amount of energy used by an electrical generator or power plant to generate one kilowatthour (kWh) of electricity. EIA expresses heat rates in British thermal units (Btu) per net kWh generated. Net generation is the amount of electricity a power plant (or generator) supplies to the power transmission line connected to the power plant. It accounts for all the electricity that the plant itself consumes to operate the generator(s) and other equipment, such as fuel feeding systems, boiler water pumps, cooling equipment, and pollution control devices.

To express the efficiency of a generator or power plant as a percentage, divide the equivalent Btu content of a kWh of electricity (which is 3,412 Btu) by the heat rate. For example, if the heat rate is 10,140 Btu, the efficiency is 34%. If the heat rate is 7,500 Btu, the efficiency is 45%.

EIA only publishes heat rates for fossil fuel-fired generators and nuclear power plants. EIA does not publish estimates for the efficiency of generators using biomass, geothermal, hydro, solar, and wind energy.

Learn more:

Historical average annual heat rates for fossil fuel and nuclear power plants.

Average annual heat rates for specific types of fossil-fuel generators and nuclear power plants for most recent year available.

EIA has data on the types and amounts of energy produced in each state:

EIA also has  the location of coal mines, electric power plants, and oil and natural gas fields in our interactive map. A short instructional video is available to learn how to use this tool.

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