What type of energy is derived from heated groundwater?

CONCEPT

Energy sources are classified by the primary natural source from which usable energy is obtained. Heat stored beneath Earth’s surface is used directly or carried upward by hot water or steam.

APPLICATION

In this item, the groundwater is already heated by heat from within Earth. Recovering that underground heat as useful energy is therefore an example of geothermal energy.

CONTRAST

• Hydroelectric energy converts the motion or gravitational fall of water into electricity; the water need not be naturally hot.

• Solar energy comes from sunlight rather than underground heat.

• Nuclear energy comes from changes in atomic nuclei, commonly controlled fission, rather than from heated groundwater.

CROSS-CHECK

If groundwater carries heat from below Earth’s surface to a well or power plant, the defining source remains Earth’s internal heat. Thus, the answer is geothermal energy.