What is the typical use of geothermal energy?

Geothermal energy is primarily used to harness heat from deep within the Earth. This energy source relies on the natural heat generated from the Earth's core and the decay of radioactive materials underground. By accessing this heat, geothermal power plants can convert it into usable energy, either for generating electricity or for direct heating applications.

The other options represent different energy practices. For example, cooling homes in the summer typically involves air conditioning systems that do not relate to geothermal processes. Generating electricity using wind pertains to wind energy, which utilizes wind turbines to capture the kinetic energy of breezes. Finally, purifying water supplies is an entirely different process usually focused on filtration and treatment methods that do not involve geothermal energy. Thus, the prevalent and correct use of geothermal energy is indeed harnessing heat from the Earth.