Geothermics is the use of the earth's heat to produce electricity, heat and cooling energy. A differentiation is made between use of the earth's heat close to the surface or near-surface geothermal energy (up to 400 metres deep) and deep geothermal energy.

The temperatures inside the earth of up to 6,000 degrees Celsius heat the upper rock and earth layers as well as underground water reservoirs. In such areas where the heat rises close to the earth's surface it is already being used to a large extent. Countries such as the USA, Iceland, New Zealand, Indonesia and the Philippines have been producing electricity from geothermal energy for a long time. In Italy geothermal electricity was first produced in 1913.

In Central Europe the temperature rises on average by around 3 °C per 100 metre depth, more in some places, such as in the Schwäbische Alb (10°C/100m). It is necessary to drill to deep temperatures to reach sufficiently high temperatures for electricity generation (geothermal power generation) and for the operation of district heating networks. The effort is worthwhile, because once tapped the geothermal energy is available practically cost-free and independent of the weather, time of day or time of year. 

Charts and Data

Heat from Renewable Energy in 2010

In 2010, Renewable Energies contributed 136 bn. kWh or 9,5 % to the german heat demand.

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