Geothermal energy comes from inside the Earth, which naturally contains heat energy. Areas where the Earth's crust is thin or fractured are ideal to extract this energy from the earth and make use of it. Iceland, for example, has many hot springs, where purely the heat of the Earth often heats water to almost its boiling point. Geothermal power stations operate by pumping water down towards the center of the Earth so that the heat turns it into the gaseous form of water called steam. This steam rises up towards the surface of the Earth again where it is used to turn turbines, which then produce electricity. Again, this is a particularly clean form of energy, however it can only be used in a limited number of places where the natural geography of the land makes it possible to access the internal heat sources of the Earth.

Wind

Solar

Hydro

Geothermal

Nuclear

Bibliography