What is geothermal energy? Definition and simple explanation:
The geothermal describes the use of heat energy that is stored in high temperatures in the ground. It is counted among the renewable energies and is also under the term geothermal known. It can be obtained both near-surface and in deeper layers of the soil existing heat to use them for heating or for the production of electricity.
Species and promotion of geothermal energy
Near-surface geothermal energy is the extraction of heat released in layers up to four hundred meters deep. In the promotion of near-surface geothermal energy groundwater wells are used as well as geothermal collectors and probes. From a depth of about fifteen meters, heat is available that is not subject to seasonal fluctuations in temperature and thus remains constant throughout the year. Although the temperatures at this depth are still comparatively low, the heat stored in the upper layers can be used as an energy source by means of thermal groundwater wells.
The temperatures of the geothermal heat increase by about three degrees Celsius per hundred meters. For depths between ten and a few hundred, sometimes even a thousand meters geothermal probes are used. In Germany alone, more than three thousand such probes - often in fields - are in operation and supply households and public buildings with heating heat. Near-surface geothermal energy is also used directly in winter to keep railway tracks, underground shafts or tunnels ice-free. Mine water in disused mine shafts can also be used thermally.
Drilling uses hot groundwater or steam at a depth of approximately four hundred meters. It is the so-called hydrothermal geothermal heat. For this purpose, the hot water is exposed in layers up to several kilometers deep by drilling holes in the surrounding rock. The water is under high pressure and usually rises on the well without further technical measures by itself. If the pressure is not high enough, the water is pumped to the surface.
Benefits of using geothermal energy
In contrast to other renewable energy sources, geothermal heat is available irrespective of weather and season, as well as permanently. This type of energy use is considered extremely environmentally friendly because geothermal plants take up only small areas and after their establishment no transport movements are needed. There are also numerous advantages for the end user in comparison to oil or gas heating systems. The supply of geothermal energy does not require storage of energy such as in oil tanks. It is odorless and associated with significantly less maintenance and thus costs for the annual Kaminkehr. In addition, geothermal energy is regarded as a price-stable type of energy supply without the risk of explosion or fire, as is always the case with gas and oil heating systems. In the summer months, near-surface geothermal energy also provides environmentally friendly air conditioning for buildings, so it can be used twice.