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, 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)
  • Kwh 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 = 0.00796 Mcf (1,000 cubic feet)
    • Petroleum = 0.00188 barrels (or 0.08 gallons)

  • Kwh 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.

Last updated: January 15, 2014


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