NGlobal Magazin 01-2010

Niedersachsen Global www.nglobal.de Energy 31 When talking about geothermal energy, i.e. power coming from heat stored at a depth of several thou- sands of metres, one is probably first reminded of bubbling geysers in Iceland, or—staying within Ger- man boundaries—perhaps the Upper Rhine Graben comes to mind. Yet now a novel technology al- so seems to allow the use of geothermal energy in northern Germany. The pilot project is called GeneSys and it is based in Hannover. In June 2009 scientists of the Federal Institute of Geosciences and Natural Re- sources (BGR) first started to drill. In 2013, or so it is hoped, the entire institute building will be heated by the energy supplied through the project. Two in One “Unlike previous technologies which used to require two bore holes, GeneSys just needs one boring,“ ex- plains project manager Dr. Michael Kosinowski. First high pressure is used to press cold water into the soil, thereby producing, at a depth of some 4,000 metres, fine cracks in the porous bunter. The water penetrates and warms up in the surroundings that are 150 de- grees Celsius warm, just like a natural heat exchanger. It then rises in the space between the water tubes and the surrounding soil. Back on the surface, the heat is extracted and fed into a circuit to then serve as heat- ing for the Institute’s offices and laboratories. Once the water has cooled down again it gets pumped back in the bore hole. With the new drilling technology Niedersachsen wants to not only show that the use of geothermal power is possible beyond southern Germany; they al- so want to reduce the cost of such projects. And there is dire need. Just one drilling devours 15 million euros of which 70 percent sink into the soil during drilling. Despite the enormous expense and efforts that are called for, geothermal power could come to play an important part. “Because geothermal power is a virtu- ally unlimited source of energy, and, what’s more, it is environmentally friendly, too.” BGR President Prof. Dr. Hans-Joachim Kümpel is full of praise. Some Like it Hot In Hannover, scientists go into new depths to prove that the use of geothermal  power is not limited to Germany’s southern provinces.  Heavy weight: BGR President Prof. Dr. Hans-Joachim Kümpel (right) is up to something big: the EUR 20,000-drill, weighing 233 kilos, is meant to help tap geothermal power. Unlike the sun or the wind, geothermal power is avail- able in any weather, 24 hours a day. Nevertheless, in the past geothermal energy has repeatedly made neg- ative headlines. Deep drilling can cause minor earth- quakes. In Hannover though, there is no such dan- ger. The main reason for this is gypsum-like bedrock which, when in contact with water during borings, expands and causes tension in the soil. In Hannover the so-called anhydride is present at a depth of 2,000 metres, but in this case the tension down below does not allow the anhydride to absorb any water. Moreo- ver, the soil in the area is not tectonically active. Deep knowledge: Due to a decade-long search for oil and gas, the amount of data about deep earth structure in Niedersachsen is un- rivalled in Germany. Photo: W. Hanke / BGR Photo: W. Hanke / BGR by Inka Ziegenhagen