Frequently Asked Questions

What is the efficiency of different types of power plants?

One measure of the efficiency of a generator or 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. The U.S. Energy Information Administration (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. Net generation 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 10,500 Btu, the efficiency is 33%. 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.  There is a discussion of the method that EIA uses to estimate the amount of energy consumed to generate electricity with renewable energy sources in Alternatives for Estimating Energy Consumption, which includes a table with estimates for the conversion efficiencies of noncombustible renewable energy sources (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

Last updated:  April 2, 2015

Other FAQs about Electricity

On This Page:


Conversion & Equivalents

Crude Oil





General Energy

Natural Gas




Full list of upcoming reports

Sign up for email notifications

Get the What's New RSS feed

Didn't find the answer to your question? Ask an energy expert.