German city of Bochum reaches milestone in geothermal development
City of Bochum in Germany successfully drilled well to tap warm water from abandoned coal mine to be used for heating of new urban area.
In the heart of the Ruhr area in Germany, a model district is currently being built in terms of climate-friendly housing, living and working. With the first geothermal well, an important step has now been taken for future heat supply, as reported by German publication ZfK.
The Ruhrgebiet (Ruhr area), is an urban area with a large number of large cities in North Rhine-Westphalia, Germany. The region is known for its heritage in coal mining, steel and heavy industry production. With a population density of 2,800/km2 and a population of over 5 million, it is the largest urban area in Germany.
Now a new city quarter in the city of Bochum has been emerging for several years. It is called “MARK 51°7“. Housing and living space, social and cultural infrastructure, as well as commercial buildings and research facilities are planned. All of this should be implemented and then operated as sustainably and climate-neutrally as possible. The project managers rely on geothermal energy for heating and cooling. The first well has now been successfully completed.
Local utility Stadtwerke Bochum, together with its subsidiary FUW GmbH, are responsible for the future heating and cooling supply of the 70-hectare site. As planned, the first geothermal well has now reached the tunnel of the former Dannenbaum colliery at a depth of 340 m. As part of “MARK 51°7”, the former tunnel is to be developed as a deep heat reservoir. The pit water should then ensure both warm feet and cool heads for the residents of the quarter.
For the heat supply, the mine water, which is around 30 degrees Celsius, is to be pumped in the future and then heated to 45 degrees Celsius using heat pumps. Water at 18 degrees Celsius is used for cooling. Due to the temperature difference between the provision of heat and cold, the two boreholes must also be of different depths. After the successful first well, the second is to follow to a depth of around 820 meters.
According to forecasts, the use of mine water should cover up to 75 percent of the heating and cooling requirements of the connected consumers in the district. The remaining heat requirement is covered by the district heating network of FUW GmbH. Cooling quantities that are additionally required on very hot days are transferred to the cooling network of MARK 51°7 via conventional cooling systems. As soon as both wells have been sunk successfully and the planned availability of the mine water has also been checked by pumping tests, the planning of the system technology within the new energy center East can be finalized.