Deep geothermal energy: An underestimated renewable energy source for district heating in Germany

Geothermal energy is considered to have a great potential as it is available year-round and without any dependence on meteorological conditions beside other renewable energy sources such as solar energy and biomass. For the exploitation of the potential of deep geothermal energy three concepts are pursued, deep geothermal probes, hydrothermal systems and petro thermal systems. Deep boreholes of several kilometers are required for the exploitation of deep geothermal potential with promising temperatures. An accurate planning and design are always necessary. A prospecting risk occurs when access to geothermal reservoirs is not provided with satisfactory heat recovery in quantity and quality with one or more boreholes. The actual temperature level of the medium transported to the surface is essential for power generation. Only some locations in Germany provide a geothermal temperature level leading to satisfying performance when using it for power generation. However, an efficient use of hot water for heating purpose can be realized with relatively low temperatures below 100°C.