Frequently Asked Questions

How much coal, natural gas, or petroleum is used to generate a kilowatt-hour 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 unit of electricity:

Amount of fuel used per kilowatt-hour (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 kilowatt-hour (kWh):
- Coal = 0.00052 Short Tons or 1.03 Pounds
- Natural Gas = 0.01003 Mcf (1,000 cubic feet)
- Residual Fuel Oil = 0.0016 Barrels

KWh generated per unit of fuel used:
- 1,942 kWh per Ton of Coal or 0.97 kWh per Pound of Coal
- 100 kWh per Mcf (1,000 cubic feet) of Natural Gas
- 610 kWh per Barrel of Residual Fuel Oil, or 14.5 kWh per Gallon

Assumptions:

Power plant heat rate = 10,300 Btu/kWh

Fuel heat contents

Coal = 20,000,000 Btu per Short Ton (2,000 lbs) Note: heat contents of coal vary widely by types of coal.

Natural Gas = 1,027,000 Btu per 1,000 Cubic Feet (Mcf)

Residual Fuel Oil = 6,287,000 per Barrel (42 gallons)

Last updated: July 16, 2012