Geothermal energy is the thermal energy stored in high pressure water zones, steam or hot water systems, or hot stone below the earth’s surface. The used thermal energy consists partly of the permanent heat flow from the earth’s core through the mantle, which ultimately releases its energy at the surface into the atmosphere. The other part originates from natural radioactive disintegration processes taking place in the mantle and releasing energy.

The use of geothermal energy can be divided roughly into near-surface or deep-seated geothermal energy. While near-surface utilization of geothermal energy supplies single buildings (or complexes of buildings) by earth heat collectors in combination with heat pumps (depth approx. 15 - 150 m) with heat, deep-seated geothermal energy offers the possibility of larger dimensioned energy supplying projects, including the generation of electric energy.

Deep-seated hydrothermal energy is the special case, that water-bearing layers (aquifers) are used in great depth (2,000 - 5,000 m). For this purpose at least two boreholes are required (production well, reinjection well) because the produced thermal water has to be reinjected into the same layer after being cooled down.

Where in Germany is hydrothermal energy possible?

In the following map of Germany the regions are marked where deep-seated hydrothermal energy projects have already been realized or a geological potential for exploitation exists according to geologists’ evaluations.

 The geologic region of the Southern German Molasse Basin has to be pointed out especially, since the successful realization of numerous heat supply projects in this area proved the feasibility, and a lower geological risk (for finding a sufficient amount of thermal water) can be assumed.