Munich taps geothermal plants outside the city for district heating

View over Munich, Germany (source: Praxisforum Geohtermie.Bayern/ Enerchange)
Alexander Richter Alexander Richter 23 May 2019

Municipal utility of Munich, Stadtwerke München (SWM) plans to optimise its geothermal power plants outside the city to connect them to its Munich district heating networks in the medium term.

The city utility of Munich in Bavaria/ Germany, Stadtwerke München (SWM), is working on expanding the three geothermal power plants in Sauerlach, Dürrnhaar and Kirchstockach, with the goal to provide thousands of households inside and outside the city with district heating.

With this goal in mind, the municipal utility has secured a permit for “Munich Suedost” from the Bavarian Ministry of Economic Affairs’s, which allows further research (into geothermal resources) of the area more closely extending far into the districts of Miesbach, Rosenheim and Bad Tölz-Wolfratshausen. This should be done with the help of seismic measurements. SWM is building a district heating network in the Ottobrunn and Hohenbrunn areas. It should be just the beginning.

With the goal of a CO2-neutral energy supply, the Munich municipal utility not only invests in wind farms in the North Sea, they also extend their efforts directly to the immediate surroundings. Last year, a complex seismic survey was conducted, in cooperation with the geothermal companies in Pullach and Grünwald, that was to determine whether further deep drilling would make sense. The first results were promising. According to Helmut Mangold, Managing Director of Innovative Energy for Pullach GmbH (IEP), the data is currently being analyzed more closely in order to better assess the potential for generating energy. He expects results at the end of June or July (2019). Then, the three partners could individually or jointly, which would offer themselves according Mangold, further power plant plans. Mangold thinks primarily of district heating.

SWM is also focusing its attention more and more on district heating. In Sauerlach, Dürrnhaar and Kirchstockach, the utility has three geothermal plants in its hands, of which Sauerlach has previously supplied district heating customers. The municipal utility wants to change that and integrate the three power plants into a district heating network, as the technical managing director of Stadtwerke, Helge-Uve Braun, announces.

The three geothermal plants should help to achieve the stated goal of the municipal utilities, to supply the city of Munich fully with renewable energy by 2040. This is to be achieved mainly with the help of deep geothermal energy. The acquisitions of Energieversorgung Ottobrunn and Bio-Energie Taufkirchen (BET) have already secured SWM a considerable pipeline network, which is currently being further expanded.

According to the plan, Energieversorgung Ottobrunn will complete the connection to the Kirchstockach geothermal plant later this year. In addition to a biomass power plant, Bio-Energie Taufkirchen also has a 40-kilometer long-distance heating network that supplies customers in Taufkirchen, Unterhaching, Hohenbrunn, Brunnthal and Neubiberg, as well as in Ottobrunn’s west. According to SWM Managing Director Braun, the utility strives for a line connection also in the Munich urban area in the medium term.

In order to be able to tackle these large and long-term goals on a solid basis, further research is planned to explore the subsurface from which the existing power plants, especially in Dürrnhaar and Kirchstockach, draw hot water. Currently, only electricity is being generated from the resources tapped by these plants.

The municipal utilities took over both geothermal plants in 2016, as we reported. As municipal utilities spokesman Michael Solic says, existing geothermal concessions have undergone potential analysis for district heating use. It has been shown that there is too little subsurface data available in the Kirchstockach and Dürrnhaar facilities.

Using seismic measurements, the plan is to explore in more detail three-dimensionally how the water-bearing layers ran and where there were fractures in the rock in order to be able to use the thermal water flows underground as “as sustainably and optimally as possible”. Where, in the next few months, the vibrating vehicles known from the in-depth investigation in the Pullach area will show up, according to Solic, it is still not clear. Currently, preparations are underway for the targeted investigation. If measurements were to be made, a separate permit would be requested from Bergamt Südbayern in the Ministry of Economic Affairs.

Source: Sueddeutsche Zeitung