The word geothermal means hot earth. As the name suggests, geothermal energy is generated from the temperature derived from earth.
The earth's core which is located at 6450 km depth is made of magma, a mixture of molten rock, volatiles and solids. This magma is very, very hot - so hot that the temperature can reach over 5000°C.
Sometimes the magma can reach the surface of the Earth and comes out from volcanoes as lava, but most of the time magma stays below the crusts. Rainfall that has seeped down into Earth is heated by magma and called geothermal water. Geothermal water that reaches to the surface forms hot springs.
However, most of the water stays deep into the ground and trapped in cracks and rocks. This will form a geothermal reservoir. By drilling down into the Earth, we can utilize the geothermal source to generate electricity without polluting the environment.
How It Makes Electricity
The hot water from geothermal reservoirs produce a stream of high pressure steam whic is used to spin a turbine that will rotate a generator.
Generators produce electricity and through power lines, bring electricity to homes and businesses.
Animation on How Geothermal Power Plant Works CLICK HERE.