At the beginning of September, the Federal Cabinet of Germany launched the Geothermal Acceleration Act (GeoWG). It aims to reduce bureaucracy and accelerate the heat transition through faster and simpler authorizations. In theory, deep geothermal energy in particular could supply entire neighborhoods with constant heat that is inexhaustible, available at all times, and, above all, climate-friendly. In practice, however, this green technology is not used anywhere near enough in Germany because there are numerous hurdles. Despite this, pioneers such as the Bavarian energy supply company Erdwärme Grünwald GmbH and Stadtwerke München have been making advances in 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 supporting the expansion of district heating pipelines and the construction of a new combined heat and power plant.
A study conducted by the Leibniz Institute for Applied Geophysics shows that there is huge potential in this area as deep and near-surface geothermal energy could supply around 40 percent of Germany’s heating needs by 2045. However, deep hydrothermal geothermal energy currently covers less than half a percent of the country’s heating needs. According to the geothermal master plan for the state of Bavaria drawn up by the Technical University of Munich, deep geothermal energy alone could cover as much as 40 percent of Bavaria’s heating needs.
“In very simple terms, deep geothermal energy is about using hot water from layers of the earth more than 400 meters deep to generate heat and, in some cases, electricity. Germany has the ideal conditions for this in the North German Basin, the Upper Rhine Plain, and southern Bavaria. In particular, the Molasse basin in southern Germany, which stretches from the Danube to the foothills of the Alps, has the largest hot water deposits in Central Europe,” explains Drees & Sommer energy expert Leonardo Estrada.
Geothermal heating networks are still rare, but they do exist, such as in the Bavarian municipality of Grünwald near Munich, for example. The Laufzorn geothermal spring there produces water at temperatures of up to 128 degrees Celsius 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 back in 2011. By 2023, the network was already around 110 kilometers long, and it now supplies heat to more than 3,500 households, businesses, and public buildings.
EUR 62.3 million from the federal government for Grünwald’s successful heat transition model
This means that every third private household in the municipality of Grünwald has achieved milestones in terms of the heating transition and climate neutrality targets – milestones that seem a distant prospect in other towns. The municipality of Grünwald saved around 22,000 tons of CO2 in 2023 by using district heating from deep geothermal energy. Further evidence of the federal government’s conviction is that the Federal Ministry of Economics approved EUR 62.3 million in funding for the planned second borehole of Erdwärme Grünwald GmbH in June.
Sleeping giant beneath our feet
“We cause more than half of the climate-damaging CO2 with our fossil heat supply, but there is a sleeping giant with a treasure trove of natural resources beneath our feet. This would enable us to guarantee a reliable, price-stable, and secure energy supply,” says Andreas Lederle, Managing Director of Erdwärme Grünwald GmbH. He continued by listing the advantages of the green energy source: “Geothermal energy is always available, regardless of the weather and does not disrupt the landscape too much. The plants are capable of providing base load and cause no environmental pollution through operation.”
However, the path to climate-friendly heat is not straightforward. “It is possible that nothing will be found in the borehole. In addition to these discovery risks, lengthy authorization processes, long project phases, and the daily requirements for smooth operation have been and continue to be major challenges. In other words, geothermal energy is cost-intensive and a long-term investment. On the other hand, we import EUR 110 billion worth of fossil fuels from abroad every year,” says Lederle. He believes a basic prerequisite for the success of deep geothermal energy is intelligent networking of district heating networks.
Expansion is progressing
The need for new transport lines for the district heating network in Grünwald is high because of the growing demand for new connections. The plan is to supply all Grünwald buildings with geothermal heat in the future. Therefore, the Grünwald energy supply company is succeeding in pushing ahead with the expansion of deep geothermal energy despite all previous hurdles.
The construction site for the northern grid 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 the north of Grünwald, which will also supply the north of Grünwald’s district heating network in the future. Commissioning is currently underway, with residents expected to receive green heat in time for the main heating period in autumn 2024. In the Bavaria Studios area, the new pipeline connects to the existing district heating network, which also contributes to greater security of supply.
Anita Beusch, Senior Project Manager at Drees & Sommer, has been working with her team to coordinate the planning and construction of the so-called northern connection. “The route runs from Oberhaching, along the forest tracks through the Perlach and Grünwald forests, to the north of Grünwald,” says the civil engineer. “For this project, particularly careful and precise execution was of utmost importance. The Perlacher and Grünwalder forest landscape conservation area and the Gleißental valley have particularly strict requirements for any intervention with machinery in order to ensure ecological functionality and minimize the impact on flora and fauna.” For this reason, the construction work was carried out in five sections as a kind of moving construction site, whereby as soon as one construction site was completed and the pipelines laid, the section was backfilled and the next construction site was worked on.
New Laufzorn II site: heat for more than 6,000 households
Erdwärme Grünwald GmbH is working flat out not only to expand the pipelines, but also to develop new sources of hot water to supply households in Grünwald and Unterhaching. To the south of the existing site in Laufzorn, the company is realizing the major “Laufzorn II” project with support from Drees & Sommer. This is another site for heat supply with a heating plant and four deep boreholes that reach a depth of around 4,000 meters. Subsequent expansion to six boreholes is possible.
“Once the last borehole has been completed and the drilling rig has been dismantled, work will begin on the surface plant and the district heating routes. A smaller heating plant is planned as only one heat extraction plant is required. In addition, many auxiliary and ancillary systems are no longer required as the infrastructure of the existing Laufzorn plant can also be utilized. As the plant will also be built on a small area of land, this will make it possible to restore a large part of the area used during the construction phase,” explains Drees & Sommer project manager Anita Beusch. Once the boreholes have been drilled, the heating plant will be built in the coming years. Laufzorn II is then planned to undergo test operation.
Heat runs like clockwork: the major Perlenschnur project
“Interconnected pipelines get the most out of the district heating potential as the district heating can be transported over longer distances with low temperature losses, meaning that fewer plants are required. The pipelines also increase the capacity utilization and reliability of the individual plants. This increases both the efficiency and cost-effectiveness of the overall system and each individual plant,” explains Erdwärme Grünwald Managing Director, Lederle.
These are good reasons why the company is working in cooperation with Stadtwerke München to set up an inter-municipal geothermal heating network called Perlenschnur. 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 bundle all the plants into a large district heating network in the future in order to supply the Bavarian capital with heat. The companies also want to develop additional geothermal plants and significantly expand their district heating networks.
When it comes to the breakthrough of deep geothermal energy on a broad scale, there is still a lot to do according to Lederle: “The focus now needs to be on establishing responsible implementation units, promoting timely research projects, reducing bureaucratic hurdles for authorization processes, enacting a geothermal development law, improving the funding environment, creating favorable project conditions, and providing financing instruments for municipalities.”
Geothermal energy act: ten times more geothermal energy by 2030
There is now good news for geothermal energy from Berlin as the Federal Cabinet passed a draft act to accelerate the authorization process for geothermal plants, heat pumps, and heat storage facilities at the beginning of September. According to the Federal Ministry of Economics, the act (GeoWG) is intended to lay the foundations for ten terawatt hours of energy to be generated from geothermal energy by 2030, which is around ten times as much as at present. [iv]
“This act shows that the federal government is taking a significant step forward in making the extraction of heat from deep geological layers less bureaucratic and, above all, faster,” explains Leonardo Estrada, geothermal expert at Drees & Sommer. “In the future, authorization processes must no longer be allowed to drag on, but must be completed in one year – not multiple years.” The German government is also planning to cover some of the exploration risks with loans from the state-owned KfW Bank. They will not only offer favorable interest conditions, but will also partially waive repayments if the geological conditions for deep geothermal energy are not met.
Images are provided here: Images of the Erdwärme Grünwald project
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