Geothermal energy is a clean renewable energy source.
The name implies the nature of the power source, geo, or from the earth, and thermal, or heat. Geothermal energy makes use both of the heat directly below the earth's surface as well as heat trapped deep below in layers of molten rock, magma. Geothermal energy can be used in many ways, from heating and cooling buildings through pumps to heating water sources and even generating electricity. The crust protects the surface of the Earth from the heat trapped within. The picture below illustrates this.