Five pilot geothermal probes have been installed and are undergoing testing as part of an underground heat storage pilot project in Buech, just west of Bern, Switzerland. The system aims to store waste heat from a waste incineration plant during summer, which can then be fed back into the district heating network in winter.
First reported in 2023, the scheme proposes the storage of excess heat from Forsthaus energy center in an underground geothermal probe field. The project aims to create an energy reserve of 12 to 15 GWh, enough to heat around 1200 to 1500 large apartments. Project implementations is being done by by Bern-based energy supplier Energie Wasser Bern (ewb).
Starting February 2025, “test pits” were excavated to followed by exploratory drilling to depths of 400 meters in April. Since the beginning of May, five pilot geothermal probes have been installed at various points in the area of the planned borehole field. These are then operated for four days during testing. Thermal response tests were conducted to determine the thermal conductivity of the subsurface and the natural subsurface temperature. The results of the exploration provide important information for the design and layout of the future borehole field.
After the tests are completed, the probes are moved to one meter below the surface so that they can be integrated later into the geothermal probe field. Three groundwater monitoring wells will also be installed starting May 2026 to help determine the status of the groundwater and the aquifer.
To reach the required capacity for seasonal heat storage, ewb needs to use a portion of the neighboring lands outside of its own property. The company has already held discussions with the landowners, with the Baumann and Begert families expressing their willingness to cooperate. Further test pits are planned in the Baumann family property in August, which is the last phase of the project’s exploratory campaign.
Source: ewb and tewag GmbH
