Geothermal Energy Wilhelmsburg
Geothermal Energy Wilhelmsburg
In the sandstone deep under the Elbe Islands, geologists expect a temperature of 130 degrees Celsius. This energy potential will be exploited by drilling to a depth of 3,000 to 4,000 metres. The vision: A geothermal power station could soon be supplying several thousand homes and other buildings in Wilhelmsburg with heat and, in the best case, even with electricity. Valuable information concerning the exploitation of geothermal power in the whole of Hamburg is expected from the research project of IBA Hamburg and its co-founded company GTW Geothermie Wilhelmsburg GmbH.
Environmentally friendly, weather-independent and emission-free geothermal energy is an energy source with a future. Thermal water from deep rock layers will be used for the supply of heat and electricity. The hot water from the layer will be pumped to the surface through a supply borehole. The heat will be extracted above ground by means of a heat exchanger, used as district heating as well as for generating electricity via a turbine an a generator from steam. The cooled water will be returned to the underground through an injection well. Underground the new hot water will continually flow to the supply borehole, therefore closing the circuit.
However, extensive seismic investigations of the rock layers were first required before this potential could be realistically estimated. The IBA Hamburg commissioned the Engineering Office GTN Geothermie Neubrandenburg to plan and prepare the seismic investigations and to evaluate the measured results.Geophysicists use „smart sound“ for these kinds of explorations. With the measuring method employed, the reflexion seismic method, the composition of the earth crust is determined down to a depth of around 4,000 metres. Vibratory vehicles send sound waves in segments into the crust of the earth along the pre-determined measurement profile, which are then reflected from the rock strata underground and sent back to the earth´s surface. Sensitive measuring instruments then record the signals received. With the stored information, a computer generates a two-dimension from which the geologists can read the location and characteristics of the rock layers.
The measurement profiles in Wilhelmsburg run along two streets: the Georg-Wilhelm-Straße in the south up to the Spreehafen in the north and along the Wollkämmereistraße, along the Wollkämmerei and the Mengestraße. The investigations lasted for about ten days.
The positive results were finally publicised in November 2010. „The results of the seismic investigation are gratifying: The main production layer is large enough to contain an adequate quantity of extractable deep ground water at a depth of 3,500 metres“, said the managing director of IBA, Uli Hellweg. The hot deep water in Wilhelmsburg is located in so-called “ Rhät”, a rock layer of the Obertrias. The water reaches a temperature of up to 130 degrees Celsius here and flows in the intermediate cavities of the rock.
Its shares have been taken over by HAMBURG ENERGIE in the meantime. For this reason, HAMBURG ENERGIE could continue expanding its heat grid of geothermal energy on the Elbe Islands as well as cross-connect the network prospectively.