Geothermal Energy
Geothermal energy is called the heat that is stored in the earth's crust and is used economically. On the Origin of geothermal energy, there are several theories. Meanwhile, it is however widely assumed that approximately one third in the Erdentstehung by accretion (accumulation of rock material by a body in space, while kinetic energy is converted to heat energy) and the greater remainder by continuous radioactive decay of isotopes (such as uranium isotopes; it has also developed thermal energy). The Earth's core is the hottest and has temperatures of up to + 5000 C, while the direct ground beneath our feet in Germany in cutting +7-10 C warm. In volcanic areas, the temperature rise is already near the surface to about 100 C +. While the air temperature varies seasonally strong, the temperature remains nearly constant under the earth. The transport of heat from the earth's interior is based on two physical phenomena: First, the heat travels through the bedrock under properties of thermodynamics from the hot to cold out.
Second, it is transported gases and magma (eg volcanoes). The man uses the geothermal heat has been around 10,000 years ago, the Neanderthals have already cooked with hot springs. The Romans enjoyed it in their spas. The modern age has multiplied the possibilities: So you used already at the beginning of the 20th century steam for heating from near-surface hot springs. In 1913 the first geothermal power plant in the world in Tuscany (Italy) was built. The steam powered turbine to generate electricity was. The research has since progressed greatly. Thus you have now the ability to create through holes in about 5000m depth (150-200 C), organic to electricity by heating water. The advantage of geothermal energy: it is an inexhaustible reservoir of energy and environmentally friendly and can always be used. Since research the economics of new, cheaper technologies has increased, it is being used more and more.