Geothermal Energy is an almost unlimited green energy source!
Geothermal power (from the Greek roots geo, meaning earth, and thermos, meaning heat) is power extracted from heat stored in the earth. This geothermal energy originates from the original formation of the planet, from radioactive decay of minerals, and from solar energy absorbed at the surface. It has been used for space heating and bathing since ancient roman times, but is now better known for generating electricity. About 10 GW of geothermal electric capacity is installed around the world as of 2007, generating 0.3% of global electricity demand. An additional 28 GW of direct geothermal heating capacity is installed for district heating, space heating, spas, industrial processes, desalination and agricultural applications.
Geothermal power is cost effective, reliable, and environmentally friendly, but has previously been geographically limited to areas near tectonic plate boundaries. Recent technological advances have dramatically expanded the range and size of viable resources, especially for direct applications such as home heating. Geothermal wells tend to release greenhouse gases trapped deep within the earth, but these emissions are much lower than those of conventional fossil fuels. As a result, geothermal power has the potential to help mitigate global warming if widely deployed instead of fossil fuels.
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. As of 2004, five countries (El Salvador, Kenya, the Philippines, Iceland, and Costa Rica) generate more than 15% of their electricity from geothermal sources.
Twenty-four countries generated a total of 56,786 GWh (204 PJ) of electricity from geothermal power in 2005, accounting for 0.3% of worldwide electricity consumption. This output is growing by 3% annually, thanks to a growing number of plants as well as improvements in their capacity factors. Because a geothermal power station does not rely on transient sources of energy, unlike, for example, wind turbines or solar panels, its capacity factor can be quite large; up to 90% has been demonstrated. Their global average was 73% in 2005. The global capacity was 10 GW in 2007.
Geothermal electric power plants have been limited to the edges of tectonic plates until recently.Geothermal electric plants have until recently been built exclusively on the edges of tectonic plates where high temperature geothermal resources are available near the surface. The development of binary cycle power plants and improvements in drilling and extraction technology has opened the hope that enhanced geothermal systems might be viable over a much greater geographical range. A demonstration project has recently been completed in Landau-Pfalz, Germany, and others are under construction in Soultz-sous-ForÍts, France and Cooper Basin, Australia.