Geothermal Energy Basics
The Earth's heat—called geothermal energy—escapes as steam at a hot springs in Nevada.
Other Resources
Geothermal Technologies Program
U.S. Department of Energy
Geothermal Heat Pumps
U.S. Department of Energy's Energy Savers
Many technologies have been developed to take advantage of geothermal energy—the heat from the earth. This heat can be drawn from several sources: hot water or steam reservoirs deep in the earth that are accessed by drilling; geothermal reservoirs located near the earth's surface, mostly located in the western U.S., Alaska, and Hawaii; and the shallow ground near the Earth's surface that maintains a relatively constant temperature of 50°-60°F.
This variety of geothermal resources allows them to be used on both large and small scales. A utility can use the hot water and steam from reservoirs to drive generators and produce electricity for its customers. Other applications apply the heat produced from geothermal directly to various uses in buildings, roads, agriculture, and industrial plants. Still others use the heat directly from the ground to provide heating and cooling in homes and other buildings.
NREL helps advance technologies for the following geothermal applications:
- Direct use — Producing heat directly from hot water within the earth.
- Electricity production — Generating electricity from the earth's heat.
- Heat pumps — Using the Earth's shallow ground temperature for heating and cooling.
Learn more about NREL's geothermal capabilities and projects related to geothermal energy.
