Geothermal energy is the power extracted from heat stored in the earth, coming from the original formation of the planet, from radioactive decay of minerals, and from solar energy absorbed at the surface. Geothermal energy doesn't create any pollution, is very efficient, an alternative source of energy, which means that by using it we get less dependent on coal and oil, and perhaps the most important advantage of geothermal energy is that, unlike energy derived from carbon-based sources, geothermal energy will never run out.