Geothermal energy is the heat from the Earth can be used as an energy source in many ways. It’s clean and sustainable and it can be found almost anywhere, as far away as remote deep wells. Resources of geothermal energy range from the shallow ground to hot water and hot rock found a few miles beneath the Earth's surface, and down even deeper to the extremely high temperatures of molten rock called magma. Geothermal energy is often used nowadays, however, to indicate that part of the Earth's heat that can, or could be recovered and exploited by human and it is in this sense that we will use the term from now on.