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Munich targeting geothermal district heating for 560,000 households

View over Munich, Bavaria/ Germany (source: Praxisforum Geothermie.Bayern)
Alexander Richter 2 Feb 2020

Stadtwerke München (SWM) pushing forward on its expansive climate targets, expecting a development that could see 560,000 households tapping into CO2 free geothermal district heating by 2040.

The utility of the city of Munich, Stadtwerke München (SWM) is confident in the implementation of its climate targets, targeting geothermal district heating for 560,000 households, as reported by Sueddeutsche Zeitung in the region.

The south of Munich, the capital of the state of Bavaria in the south of Germany, and in particular all the southern neighbouring region are to become the key supplier of CO?-free district heating for the state capital. Stadtwerke München (SWM) is relying on the expansion of existing geothermal plants and wants to build new plants in Berg am Laim, but also in Baierbrunn in the Isar Valley, which will send hot water to households in Munich in the medium term. The head of geothermal energy development at SWM, Dietfried Bruss, estimated the usable potential for geothermal energy at a recent press appointment at 350 to 400 MW (thermal), which, according to him, corresponds to the heat consumption of 560,000 households.

The SWM are generally not modest when it comes to statements about the energy potential in Munich’s underground. This is due to the geologically unique location of the city, under which large amounts of hot water, which basically only have to be tapped, collect in a Malm layer coming from the low mountain ranges and descending to below the Alpine ridge. High temperatures are to be expected especially in the south of Munich. Of course, this requires complex drilling down to a depth of thousands of meters, which are not necessarily guaranteed to be successful. However, drilling and mining technology are making progress, and the methods of investigation are also improving, in which three-dimensional images of the subsurface can be created with the help of sound waves.

Recently, such a seismic survey, which the SWM had carried out together with the geothermal operators in Pullach and Grünwald, delivered encouraging results in the Isar Valley. There was soon talk of a “thick, fat potential” for a geothermal power plant. On February 1, the municipal utility started another investigation in a 177 square kilometer area in the Ottobrunn and Brunnthal area, which extends to the districts of Ebersberg and Miesbach.

During the press conference that SWM held in Brunnthal for this reason, geothermal project manager Bruss discussed the entire plans of the municipal utility company, which are to be implemented by 2040. The self-imposed climate target is to massively expand district heating in the city by then and cover the heating requirement in a CO2-neutral manner.

Stadtwerke is working in many places to find alternatives to coal burning in the north thermal power station in Unterföhring, in addition to the geothermal power plants in Riem and Freiham. The construction of the “largest geothermal energy project in Europe” with a capacity of 50 MW, as Bruss called it, is making good progress in the middle of the city at the southern heating plant. Bruss said drilling of the last of the six wells is nearing completion. The plant could cover the heating needs of 80,000 households. A plant of the same size is under discussion in Berg am Laim. A multiple of its performance is said to be “to be developed in the south of Munich in the next few years,” said Bruss. The “basic supply” of the state capital should succeed with heat from geothermal energy.

The plans in the Isar valley, where SWM plans to build a power plant in Baierbrunn after the promising seismic study in 2018, are the most advanced. According to Bruss, six wells are also planned for this and it should also have an output of 50 MW. The decisions on this project have been made, said Bruss, the exact location has not yet been determined.

In the Ottobrunn and Brunnthal area SWM can build on existing structures, where the underground is now to be explored. In 2016, the company bought two geothermal power plants from private operators in Kirchstockach (municipality of Brunnthal) and Dürrnhaar (municipality of Aying). Together with the plant in Sauerlach, SWM fetches hot water from below at three locations. In addition, SWM took over the Ottobrunn energy utility, a small company that invests heavily in the district heating network in the suburbs. SWM also owns a biomass power plant in Taufkirchen and the connected district heating network. However, according to Bruss, the actual goal is to make the three plants usable for Munich and to create a connection to the city.

But there is still a lot to do until then: Kirchstockach and Dürrnhaar are currently only producing electricity and, as Bruss said, are not nearly exhausting their capacities. He announced a switch to district heating and said that a line to Munich would be built. The seismic survey, Bruss said, should show whether the performance of the plants could be increased with the help of further drilling, or even an additional power plant would be useful.

Source: Sueddeutsche Zeitung