Geothermal energy is continuously created beneath the Earth's surface from the extreme heat contained in liquid rock (called magma) within the Earth's core. When this heat naturally creates hot water or steam, it can be piped to the surface and then used to turn a steam turbine to generate electricity. Geothermal energy also can be obtained by piping water underground to extract heat from hot, dry rocks. Heat is then returned to the surface to turn a steam turbine and generate electricity.

 

Geothermal technologies do not produce a substantial amount of solid waste or air pollution while creating electricity. (Source: EPA / Photo: Flickr)