Geothermal Renewable a Power Source:

Geothermal power (from the Greek roots geo, meaning earth, and thermos, meaning heat) is energy generated from heat stored in the earth, or the collection of absorbed heat derived from underground.

Prince Piero Ginori Conti tested the first geothermal generator on 4 July 1904, at the Larderello dry steam field in Italy. The largest group of geothermal power plants in the world is located at The Geysers, a geothermal field in California, United States. The Philippines and Iceland are the only countries to generate a significant percentage of their electricity from geothermal sources; in both countries 15-20% of power comes from geothermal plants. As of 2008, geothermal power supplies less than 1% of the world's energy. The most common type of geothermal power plants (binary plants) are closed cycle operations and release essentially no Greenhouse gas emissions; geothermal power is available 24 hours a day with average availabilities above 90% (compared to about 75% for coal plants).

Geothermal resources range from shallow ground to hot water and rock several kilometres below the Earth's surface, and even further down to the extremely hot molten rock called magma. Wells over 1.5 km deep can be drilled into underground reservoirs to tap steam and very hot water that can be brought to the surface for use in a variety of applications.

Geothermal power requires no fuel, and is therefore virtually emissions free and insusceptible to fluctuations in fuel cost. And because a geothermal power station doesn't rely on transient sources of energy, unlike, for example, wind turbines or solar panels, its capacity factor can be quite large; up to 90% in practice.

It is considered to be sustainable because the heat extraction is small compared to the size of the heat reservoir. While individual wells may need to recover, geothermal heat is inexhaustible and is replenished from greater depths. The long-term sustainability of geothermal energy production has been demonstrated at the Lardarello field in Italy since 1913, at the Wairakei field in New Zealand since 1958, and at The Geysers field in California since 1960.

Geothermal has minimal land use requirements; existing geothermal plants use 1-8 acres per megawatt (MW) versus 5-10 acres per MW for nuclear operations and 19 acres per MW for coal power plants. It also offers a degree of scalability: a large geothermal plant can power entire cities while smaller power plants can supply more remote sites such as rural villages.

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