What is energy from the internal heat of the Earth called?

Energy from the internal heat of the Earth is called geothermal energy. The word combines the Greek roots geo, meaning Earth, and thermos, meaning heat. It refers to heat stored beneath the surface and the usable power obtained from it.

Earth’s internal heat has two main origins: leftover heat from the planet’s formation and heat released by the radioactive decay of elements such as uranium, thorium, and potassium. That energy moves through rock and underground water, sometimes reaching the surface as hot springs, geysers, or volcanic activity.

People use geothermal energy directly to heat buildings, bathe in hot springs, and support industrial processes. In suitable locations, wells bring hot water or steam to the surface to drive turbines and generate electricity. Geothermal heat pumps use the relatively stable temperature of shallow ground for heating and cooling.

It is considered renewable because Earth continually produces internal heat, although individual reservoirs can be depleted if extraction is faster than natural replenishment. The strongest resources are often found near tectonic plate boundaries, where hot rock and magma lie closer to the surface.