Geothermal hot springs in Yellowstone, US. (Source: © Brad Pict / stock.adobe.com)

Natural heat inside the Earth produced by the decay of radioactive elements in the Earth’s interior. The word geothermal comes from the Greek “geo” (earth) and “therme” (heat). This heat can be transported by processes in the Earth’s mantle to near the surface, where it can manifest itself in a variety of ways, such as volcanoes, geysers, hot springs, or fumaroles. Geothermal energy can be used to heat homes, greenhouses, or to generate electricity in geothermal power plants.