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Geothermal Energy Basics

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.

Photo of a hot spring.

The Earth's heat—called geothermal energy—escapes as steam at a hot springs in Nevada.

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:

  • Heat pumps — Using the Earth's shallow ground temperature for heating and cooling.
  • Electricity production — Generating electricity from the earth's heat.
  • Direct use — Producing heat directly from hot water within the earth.

Learn more about NREL's geothermal research.

Additional Resources

For more information about geothermal technologies, visit the following resources:

Geothermal Technologies Program
U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy

Geothermal Energy Consumption Data
U.S. Energy Information Administration

Geothermal Prospector Tool
NREL's Geographic Information System Application

Geothermal Heat Pumps
U.S. Department of Energy's Energy Savers Program

Energy Kids Geothermal Basics
U.S. Energy Information Administration Energy Kids

Clean Energy Education and Professional Development
U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy.