Read the following paragraph and answer the question. Give ONLY the answer, no other words or explanation.

For example:

Answer: <most likely answer, as short as possible>.

Paragraph: 
Heat below Earth’s surface—called geothermal energy— can be used to produce electricity. A power plant pumps water underground where it is heated. Then it pumps the water back to the plant and uses its thermal energy to generate electricity. On a small scale, geothermal energy can be used to heat homes. Installing a geothermal system can be very costly, however, because of the need to drill through underground rocks.


Question: What do you call the heat below earth’s surface that can be used to produce electricity?
geothermal energy
Geothermal energy.