In places where the earth's crust is thin superheated geothermal fluid escapes to the surface through fissures in the rock. Geothermal generation converts the heat of naturally occurring steam and hot water into electricity.
Geothermal energy is clean energy because no fuel is burned, so there are no harmful pollutants released into the environment. Geothermal power plants use steam from wells that reach deep in the earth into geothermal reservoirs. These reservoirs are usually found along the earth's major plate boundaries where volcanoes and earthquakes occur most frequently. Since there are no physical signs above ground for geothermal reservoirs, geologists have to drill a well and test the temperature of the ground to see if there is a reservoir that can be used.