Generating Electricity from Geothermal Energy

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.

There are three types of geothermal energy used to make electricity:

Hydrothermal - Uses steam and hot water
Geopressurized - Uses hot water (around 350 degrees Fahrenheit) and hydraulic turbines
Petrothermal - Uses dry hot rocks requiring water injections to make steam

The most widely used process is hydrothermal, where steam is pumped from wells directly from the reservoir to a giant turbine. The turbine spins a magnet which generates electricity.