Geothermal power is electricity generated by utilizing naturally occurring geological heat sources. Geothermal power is generally harnessed in one of three ways. Large scale electrical generation is possible in areas near geysers or hot springs by utilizing naturally occurring steam, superheated ground water or using geothermal heat to heat a heat-transfer fluid. Experiments are testing whether deep wells into hot dry rocks can be economically used to heat water pumped down from the surface. It is a renewable energy method.
Geothermal-generated electricity was first produced at Larderello, Italy, in 1904. Since then, the use of geothermal energy for electricity has grown worldwide to about 8,000 megawatts of which the United States produces 2700 megawatts. Geothermal power is generated over 20 countries around the world including Iceland, United States, Italy, France, New Zealand, Mexico, the Philippines, Indonesia and Japan. The largest dry steam field in the world is The Geysers, about 90 miles north of San Francisco begun in 1960 which produces 2000 MWe.
See also Geothermal heating