Geothermal Energy

The Geothermal Energy Association defines geothermal energy as heat that comes from the earth. It can used for electricity generation or for home heating. Geothermal power plants produce electricity by drilling into natural hot water or steam reservoirs. When the reservoir fills, wells bring the geothermal liquid to the earth’s surface, where it spins a turbine and is converted into electricity at a power plant. Currently, there are three types of geothermal power plants in widespread use and several other designs under development.

This dry-steam power plant example shows how steam from a geothermal well can be used to turn a turbine and produce electricity.
Source: EERE

Nationwide, geothermal energy is the fourth largest source of renewable energy, after hydroelectric, biomass, and wind. Geothermal power plant capacity in the United States is approximately 3 GW. Reservoirs of hot water and steam are located primarily in the Western United States, Alaska, and Hawaii. In total, 69 generating facilities are in operation at 18 sites around the country, and the Western Governors’ Association recently identified an additional 100 sites with near-term development potential.

Sources:

• U.S. Department of Energy, Energy Efficiency and Renewable Energy Agency
• Geothermal Energy Association