Continental Europe might not be able to offer the same outstanding conditions as geologically active Iceland, but geothermal energy remains, as far as we know, an unlimited source of energy. The energy is constantly available and without seasonal fluctuations. In Central Europe where the ground temperature increases by 3°C per 100m, deep boreholes can quickly reach two-digit temperature differences compared to the surface. Water is heated in a closed circuit and then used to drive a turbine.
However, after a 5km-deep geothermal borehole in Basel, Switzerland, caused a minor earthquake in 2007 (around 3.3 in magnitude), the expansion of geothermal activities came to a standstill, particularly in densely populated areas. Nevertheless, the technology continues to be extremely attractive for the energy industry.
The municipal utilities of the Bavarian capital of Munich have set themselves ambitious targets when it comes to providing its inhabitants with a sustainable supply of energy. Electricity generation, for instance, is to be secured exclusively through renewable energy sources by 2025 and then by 2040 the provision of heating for the city. Geothermal energy is to play an important role in the supply of heating. A total of nine boreholes are planned in the city area. For this reason, Stadtwerke München and the University of Munich are currently researching new methods in order to understand better the potential effects of geothermal energy in urban environments. The project has been subdivided into the sub-areas of cause determination, impact assessment and verification. Knowledge about the condition of the soil will, for instance, enable a differentiated assessment of the urban area in terms of the risk of potential earthquakes. Ultimately, the aim of the project will be to ensure that the local inhabitants have a constant supply of energy.