A Clear Commitment to Geothermal Energy: How Potsdam Is Building the Heating Supply of the Future with GFZ Support
By: Robert Buluma
It is a project that resonates far beyond the borders of Brandenburg: In June 2026,Energie und Wasser Potsdam GmbH (EWP) and the GFZ Helmholtz Centre for Geosciences signed a landmark project agreement for the geothermal development of additional sites in the state capital. The contract marks the starting signal for four years of intensive collaboration as part of the "Heat with Geothermal Energy" cooperation program and runs until the end of 2029. The goal is to systematically develop Potsdam's geothermal potential and integrate it into the municipal heating supply over the long term.
A Successful Predecessor Paves the Way
The new cooperation builds on an impressive foundation: EWP's first major geothermal project at Heinrich-Mann-Allee has already demonstrated the enormous potential of geothermal energy in Potsdam. Originally planned for an expected output of around two megawatts (MW), the system exceeded all expectations – the actual thermal output today exceeds four MW.
Carsten Schulte, Technical Managing Director of EWP, explained at the contract signing: "This system alone will feed more than 4 megawatts of thermal output into our heating network in the future – enough to supply over 6,000 households. The collaboration with the GFZ and their expertise enables us to transfer this successful concept to additional sites."
The Heinrich-Mann-Allee facility, built on the site of the former tram depot, went into operation in 2025. The boreholes reached a final depth of up to 2,157 meters. Since the start of the heating season in autumn 2025, the adjacent new-build district with around 340 apartments has been fully supplied with deep geothermal energy. This makes it one of the first districts in Germany to be supplied almost autonomously with deep geothermal heat.
What makes this project particularly remarkable is its urban integration: the facility was built in the middle of a densely populated area. Once drilling was completed, the 33-meter-high drilling rig, visible from afar, was dismantled. Most of the technology is now hidden underground or within a compact operations building, allowing green spaces and recreational areas for local residents to be created above the facility. EWP invested around 20 million euros in this pioneering project – a bold step that has now paid off.
The GFZ – Germany's Competence Centre for Geothermal Energy
The GFZ Helmholtz Centre for Geosciences is Germany's national research centre for the geosciences. It researches the Earth system and its dynamics, providing scientific foundations for the sustainable use of geological resources. The GFZ is regarded as a nationwide pioneer in the field of deep geothermal energy and possesses outstanding scientific expertise in geothermal research – from exploration and reservoir development to management and monitoring.
"With this cooperation, we are combining research and practice in an exemplary way," said Prof. Dr. Susanne Buiter, Scientific Director of the GFZ. "Geothermal research is of outstanding importance at the GFZ because the use of geothermal energy can make a significant contribution to the urgently needed heating transition. The geological conditions in our region are favourable, and we are happy to contribute to unlocking this resource."
Prof. Dr. Ingo Sass, project leader on the GFZ side and head of the Geoenergy Section, added: "As part of the North German Basin, the geology in Berlin-Brandenburg offers at least half a dozen hydrothermal layers. In Potsdam, multiple reservoir horizons could be developed and utilised for the first time. This would be a milestone for geothermal heating supply with a signal effect far beyond the North German Basin."
The Geological Opportunity: The North German Basin
The geological conditions for geothermal energy in Potsdam are exceptionally favourable. The region is part of the North German Basin, which possesses the largest geothermal potential in Germany. This is due both to its enormous extent and to the elevated temperatures of water-bearing rock layers in many areas. On average, temperature increases by 32 Kelvin per kilometre in the North German Basin.
The subsurface of the North German lowlands is traversed by water-bearing, porous sandstone layers that provide optimal conditions for geothermal energy use. The basis for this type of utilisation is an existing water-bearing rock layer – an aquifer – with sufficient temperature and yield, which can be drilled into.
The North German Basin harbours potentially promising medium-depth geothermal reservoirs, particularly in the calcarenites of the Reitbrook Formation from the Upper Maastrichtian. The geological diversity enables the development of various hydrothermal layers – a decisive advantage for the planned multi-layer utilisation in Potsdam.
However, the North German Basin also presents technical challenges. The saline formations – salts and sulphates such as gypsum – make the thermal water highly corrosive and promote sulphur-containing deposits. This requires special materials and sophisticated operating strategies to ensure long-term reliable and economical extraction. This is where the GFZ brings its many years of research experience to bear.
The GFZ's Role in Geothermal Research
Over many years, the GFZ has established itself as one of the leading research institutions in the field of deep geothermal energy. The Geoenergy Section, under the leadership of Prof. Dr. Ingo Sass, researches the entire value chain of geothermal energy production – from exploration and characterisation of geothermal reservoirs, through development of exploration and monitoring methods, to assessment of sustainability and environmental compatibility.
The GFZ's scientific expertise includes:
· Exploration: Geological, geophysical, and geochemical methods for identifying and evaluating suitable geothermal reservoirs
· Reservoir Development: Development of drilling strategies and extraction methods for efficient and sustainable production
· Management: Optimisation of geothermal system operation considering reservoir behaviour and long-term stability
· Monitoring: Continuous subsurface monitoring to ensure operational safety and environmental protection
The GFZ has already demonstrated its competence in the region in the past. For example, borehole geophysical measurements were conducted on geothermal wells in Potsdam and other locations in Mecklenburg-Western Pomerania. Temperature logging and measurements of thermal-hydraulic rock properties on drill cores are also part of the GFZ scientists' standard repertoire.
Technical Implementation: How Geothermal Energy Works
The planned geothermal development in Potsdam is based on the principle of hydrothermal geothermal energy. Hot thermal water is extracted from deep rock layers, its heat energy is transferred to a district heating circuit, and the cooled water is returned to the subsurface – a closed loop that is sustainable and resource-efficient.
The specific technology works as follows: A hydrothermal doublet – that is, two deep boreholes – is drilled. A production well extracts the hot thermal water to the surface using an electrically driven deep-well pump. There, pipes and a heat exchanger transfer the thermal energy to the district heating circuit. The cooled thermal water is then returned to the subsurface via the injection well.
The heat from the deep geothermal facility is fed into the district heating network via heat pumps at an energy centre. The heat exchanger and other system components such as filters, pressure maintenance equipment, and valves are housed in an adjacent energy centre, while the wellheads are installed directly on the boreholes, partly in an underground basement.
For the planned project in Gartenstraße in Potsdam-Babelsberg, a doublet at an expected vertical depth of around 950 metres (borehole length approx. 1,600 metres) is envisaged. The deep boreholes will be deviated to prevent hydraulic-thermal interference, ensuring sustainable operation. The target thermal output is around four MW – a figure based on the successful pilot project.
A Master Plan for Potsdam's Heating Future
The new cooperation is part of a more comprehensive strategic restructuring of Potsdam's heating supply. The existing combined heat and power plant, which has been in operation since 1995, is to be gradually replaced. The technical systems are reaching the end of their service life, and the first replacement step must be completed by 2030.
In total, EWP is planning eight deep geothermal projects. Additional sites are planned in Babelsberg and in southern Potsdam (Potsdam-Süd). In the future, heat will be generated decentrally at multiple locations – using deep geothermal energy, river water heat, combined heat and power plants, and power-to-heat facilities.
Monty Balisch, Commercial Managing Director of EWP, emphasised: "The combined heat and power plant has served us very well since 1995. Now the technical systems are reaching the end of their service life, and we must achieve the first replacement step by 2030. In future, heat for Potsdam will be generated decentrally at several locations – using deep geothermal energy, river water heat, and supplemented by combined heat and power plants and power-to-heat facilities. In this way, we not only meet legal requirements but also ensure a future-proof, independent, and affordable heating supply for our city."
The prospect of developing and utilising multiple reservoir horizons for the first time in Potsdam is particularly promising. This would be a milestone for geothermal heating supply with a signal effect far beyond the North German Basin. The geological diversity of the region enables various hydrothermal layers to be tapped, increasing supply security and reducing dependence on individual reservoirs.
Geothermal Energy as a Key to the Heating Transition
The importance of deep geothermal energy for Germany's energy transition can hardly be overstated. The potential in Germany is remarkable: over 300 terawatt-hours per year, equivalent to approximately a quarter of Germany's total heat demand. Nevertheless, geothermal and ambient heat currently account for only about 1.9 percent of Germany's heat generation mix.
The federal government has set itself the goal of massively expanding deep geothermal energy. By 2040, 25 percent of heat demand could be covered by deep geothermal energy. However, this requires significant investment, political support, and above all, close collaboration between science and industry – exactly as is now being practised in Potsdam.
Geothermal energy offers decisive advantages over other renewable energy sources: it is baseload-capable, weather-independent, and available around the clock. Unlike solar or wind power, it delivers heat constantly, regardless of time of day or season. Moreover, it is locally available and reduces dependence on energy imports.
Challenges and Solutions
Despite all the opportunities, deep geothermal energy faces challenges. The "discovery risk" – the risk of not finding enough hot water – is high with the first borehole. EWP invested around 20 million euros in the Heinrich-Mann-Allee pilot project – a considerable financial risk. The success paid off, but not every project will be so fortunate.
Other challenges include high investment costs, lengthy approval procedures, and technical risks such as corrosion or scaling in the boreholes. This is where research comes in: the GFZ is working on improved exploration methods to minimise discovery risk, and on new materials and operating strategies to extend the service life of facilities.
The close cooperation between EWP and GFZ is a model for how these challenges can be overcome. The GFZ's scientific expertise reduces risk for the investor, while EWP's practical experience brings research findings into application. This continuous exchange between theory and practice is crucial for the success of the heating transition.
A Model for Germany
The Potsdam model could set a precedent. The combination of a municipal utility taking economic responsibility and a renowned research institute contributing scientific expertise is a success formula that can be transferred to other cities and regions.
EWP, as the project sponsor, is responsible for overall planning and investment, technical implementation, and integration into the urban heating network. It also bears the economic responsibility for implementation and finances the necessary investments in infrastructure, plant construction, and network integration. The GFZ contributes its scientific expertise in exploration, reservoir development, management, and monitoring.
This division of labour has already proven itself in the first project. The GFZ had already collaborated on the Heinrich-Mann-Allee site. The cooperation is now being intensified and extended to additional sites.
Outlook: Until 2029 and Beyond
The project agreement runs until the end of 2029. During this period, several new geothermal facilities are to be built in Potsdam. Planning for the site in Gartenstraße in Babelsberg is already well advanced. There, construction of a geothermal facility with a hydrothermal doublet and associated energy centre is planned to achieve a thermal output of around four MW.
Additional sites are under discussion, including Brauhausberg and areas in Nedlitz. EWP has announced that the planned projects are "close to the start of construction." The gradual replacement of the combined heat and power plant by 2030 is an ambitious but achievable goal.
Beyond 2029, cooperation could continue. The insights gained from Potsdam's geothermal energy will benefit not only the state capital but also other regions in Germany and beyond. The project's signal effect extends far beyond the North German Basin.
Conclusion: A Milestone for the Heating Transition
The signing of the project agreement between EWP and GFZ is more than just a formality. It is a clear commitment to geothermal energy as a central component of future heating supply. Potsdam is showing how the heating transition can succeed in practice: with scientific excellence, entrepreneurial courage, and clear strategic direction.
The Heinrich-Mann-Allee pilot project has proven that deep geothermal energy works in Potsdam – and better than expected. The systematic development of additional sites now beginning will increase supply security, reduce dependence on fossil fuels, and make a significant contribution to climate protection.
The close collaboration between research and practice, between GFZ and EWP, is the decisive success factor. It combines scientific excellence with entrepreneurial implementation capability, creating the foundation for a future-proof, independent, and affordable heating supply in Potsdam.
As Prof. Dr. Susanne Buiter succinctly put it: "The use of geothermal energy can make a significant contribution to the urgently needed heating transition. The geological conditions in our region are favourable, and we are happy to contribute to unlocking this resource."
Potsdam is leading the way – and showing that the heating transition is not only possible but already in full swing.
See also: Fervo Energy, PNNL, and NVIDIA Forge AI-Powered Digital Twin to Revolutionize Geothermal Development
Source: GFZ
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