Our ancestors have used geothermal energy for cooking and bathing since prehistoric times. Today, we use this enormous energy reservoir to supply millions of people with clean, low-cost electricity.
Geothermal energy is the heat contained below the Earth's crust.
Most of the country's geothermal resources are located in the western U.S. Geothermal Power Plants Geothermal power plants use wells to pipe steam and hot water trapped underground to the surface to make electricity. Currently, U.S. geothermal power plants have a total generating capacity of 2,700 megawatts, enough electricity to power the homes of more than 3.5 million people. The power plants produce electricity at 5 to 7.5 per kilowatt-hour. Hydrothermal Reservoirs Hydrothermal reservoirs are large pools of steam or hot water trapped in porous rock. To create electricity, the steam or hot water is pumped to the Earth's surface where it drives a turbine that spins an electric generator.