Munich, Germany, September 12, 2024. A week ago, the German federal cabinet introduced the Act on Accelerating the Approval of Geothermal Systems, Heat Pumps and Heat Storage Facilities or ‘Geothermal Heat Acceleration Act’ (Gesetz zur Beschleunigung der Genehmigung von Geothermie-Anlagen, Wärmepumpen sowie Wärmespeichern – GeoWG). What sounds cumbersome is intended to reduce bureaucracy and promote the heating energy transition through faster and simpler approvals. In theory, deep geothermal energy in particular could supply entire urban districts with constant heat: inexhaustible, available at all times and, above all, climate friendly. But in practice, this green technology is used far too little in Germany due to numerous hurdles. Yet pioneers such as the Bavarian energy supply company Erdwärme Grünwald GmbH and Stadtwerke München (Munich's municipal utility company) have been driving forward the use of deep geothermal energy for a long time. The consulting firm Drees & Sommer SE, which specializes in construction, real estate and infrastructure, is providing support for the expansion of district heating pipelines and the construction of a new combined heat and power plant.
The potential is enormous. According to a study by the Leibniz Institute for Applied Geophysics, deep and near-surface geothermal energy could supply around 40 percent of Germany's heating requirements by 2045. However, hydrothermal deep geothermal energy currently covers less than half a percent of heating requirements in Germany. The Masterplan Geothermie Bayern (‘master plan for geothermal energy in Bavaria’) published by the Technical University of Munich (TUM) nevertheless indicates that as much as 40 percent of Bavaria's heating requirements could be met by deep geothermal energy alone.
“In very simple terms, deep geothermal energy involves using hot water from layers of the Earth more than 400 meters deep to extract heat and, in some cases, to generate electricity. Optimum conditions for this exist in Germany in the North German Basin, in the Upper Rhine Rift Valley and in southern Bavaria. The largest occurrence of hot water in Central Europe is found particularly in the southern German Molasse Basin, which extends from the Danube to the Alpine foreland,” explains Drees & Sommer’s energy expert Leonardo Estrada.
As marvels of heating, geothermal heating networks are still rare, but they do exist: for example in the Bavarian municipality of Grünwald near Munich. That is where the Laufzorn geothermal spring produces water at temperatures of up to 128 degrees from a depth of more than 4,000 meters. The first households, businesses and municipal facilities in Grünwald were connected to the district heating network as early as 2011. By 2023, its length had reached around 110 kilometers. It now supplies more than 3,500 households, businesses and public buildings with heating.
62.3 Million in Federal Funding for Grünwald’s Successful Approach to the Heating Energy Transition
This means that one in three private households in the municipality of Grünwald meets targets that seem a long way off elsewhere, with regard to the heating energy transition and net zero carbon. The municipality of Grünwald saved around 22,000 metric tons of CO2 in 2023 by using district heating from deep geothermal energy. These are facts that the German federal government also finds convincing. In June, the German Federal Ministry for Economic Affairs and Climate Action (BWMK) approved 62.3 million euros in funding for the planned second borehole by Erdwärme Grünwald GmbH.
Sleeping Giant Beneath our Feet
“We cause more than half of the harmful CO2 with our fossil-based heating supply. Yet we have a sleeping giant with a natural resource on every level beneath our feet. This could guarantee a reliable, price-stable and secure energy supply,” says Andreas Lederle, Managing Director of Erdwärme Grünwald GmbH, and emphasizes the advantages of green energy sources. “Geothermal energy is always available, independent of the weather and does not have a noticeable effect on the landscape. The plants are capable of providing base load and their operation does not cause environmental pollution.”
But the path to climate-friendly heating is not an easy one. Andreas Lederle explains: “It is possible that nothing will be found in the borehole. In addition to these discovery risks, lengthy approval procedures, long project periods and the daily requirements for smooth operation were and still are major challenges. Geothermal energy is cost-intensive as a result; it is a marathon rather than a sprint. Yet we import 110 billion euros worth of fossil fuels from abroad every year.” In his view a basic requirement for the success of deep geothermal energy is the intelligent networking of district heating networks.
Expansion Is Progressing
As a result, there is a correspondingly high need for new transport pipelines for the district heating network in Grünwald due to the growing demand for new connections. The plan is to supply all of Grünwald’s buildings with geothermal heating in the future. And so the Grünwald-based energy supply company is succeeding in pushing ahead with the expansion of deep geothermal energy, despite all the hurdles it has faced to date.
The construction site for the northern network connection in Bavaria Filmstrasse was completed on schedule. This is an approximately 4.7 km long district heating transport pipeline between the Laufzorn and Unterhaching sites and north Grünwald, which will also supply the north of Grünwald's district heating network in future. Commissioning is currently underway, so residents are expected to receive green heating in time for the main heating period in the fall of 2024. In the area of the Bavarian Film Studios, the new pipeline connects to the existing district heating network, which also contributes to greater security of supply.
Together with her team, Anita Beusch, senior project head at Drees & Sommer, coordinates planning and construction of the new district heating pipeline called Nordanbindung (‘northern connection’). The civil engineer comments: “The route runs from Oberhaching along the forest paths through the Perlach and Grünwald forests to the north of Grünwald. Particularly careful and precise implementation was the top priority for the project. In the Perlach and Grünwald Forest landscape conservation area, including the Gleissental valley, there are particularly strict requirements for intrusion using machinery. The aim here is to ensure ecological functionality and to minimize the impact on flora and fauna.”
For this reason, the construction work was carried out in five sections, as a kind of traveling construction site: as soon as an area was finished and the pipelines laid, the section was backfilled and the next area was dug up.
New Site Laufzorn II: Heating more than 6,000 Homes
Erdwärme Grünwald GmbH is working hard not only to expand the pipelines, but also to develop new sources of hot water to supply households in Grünwald and Unterhaching. With the support of Drees & Sommer, the firm is realizing the large-scale project Laufzorn II to the south of the existing site in Laufzorn. This is another site for the supply of heating, with a heating plant and four deep boreholes that reach around 4,000 meters. It would be possible to expand to six boreholes at a later stage.
“After completion of the last borehole and dismantling of the drilling rig, work begins on the surface facility and the district heating routes. A smaller heating plant is planned, as only one heat extraction system is needed. In addition, many auxiliary and ancillary facilities are no longer required because the infrastructure of the existing Laufzorn plant can also be used. As the plant is also being built on a small area of land, this allows a large part of the site used during construction to be renatured,” points out Drees & Sommer’s project head Anita Beusch.
Once the drilling has been completed, the heating plant is to be built in the coming years. A test run for Laufzorn II is then planned.
Heating System Running like Clockwork: Perlenschnur (‘string of pearls’) as a Major Project
“Interconnected pipelines make optimum use of the potential for district heating, as it can be transported over longer distances with low temperature losses. Fewer facilities are required as a result. The pipelines also increase capacity utilization and the reliability of the individual systems. This raises both the efficiency and cost-effectiveness of the overall system and each individual plant,” says Erdwärme Grünwald’s Managing Director Andreas Lederle.
These are good reasons why the company, in partnership with Stadtwerke München, is planning to set up an inter-municipal geothermal heating network called Perlenschnur (‘string of pearls’). It is so called because the eight geothermal projects in the south of Munich, including the Laufzorn and Laufzorn II sites, are strung together like pearls on a string. The aim of the joint project between the two energy suppliers is to pool all the facilities in one large district heating network in future, in order to supply the Bavarian capital with heating. The companies also intend to develop further geothermal plants and significantly expand their district heating networks.
According to Andreas Lederle, there is still a lot to do in order to achieve a breakthrough in the general use of deep geothermal energy “The focus must now be on establishing responsible implementation units, funding timely research projects, reducing bureaucratic hurdles for approval procedures, enacting a geothermal energy development act, improving the funding environment, creating favorable project conditions and providing financing instruments for municipalities.”
Ten Times more Energy from Geothermal Energy by 2030
There is now good news from Berlin for geothermal energy: at the beginning of September, the cabinet passed a draft law to speed up the approval process for geothermal energy plants, heat pumps and heat storage systems. According to the Federal Ministry for Economic Affairs and Climate Action, the German Geothermal Heat Acceleration Act (GeoWG) is intended to lay the foundations for ten terawatt hours of energy to be generated from geothermal energy by 2030 – around ten times as much as at present.
Leonardo Estrada, Drees & Sommer’s expert for geothermal energy projects, says: “By adopting this legislation, the German government is taking a significant step forward in making the extraction of heat from deep layers of the earth less bureaucratic and, above all, faster.
In future, approval procedures will no longer be allowed to drag on, but must be completed within one year instead of many years.” The German government also plans to partially cover the discovery risks with loans from the state-owned reconstruction and development bank KfW. These loan arrangements should not only offer favorable interest terms, but also partially waive repayments if the geological conditions for deep geothermal energy are not met.
For pictures please click here: Pictures of the Erdwärme Grünwald project