KEA-BW / triolog
Geothermal probes are not only interesting for new buildings. They can also be useful for supplying heat to existing buildings. The KEA Climate Protection and Energy Agency Baden-Württemberg (KEA-BW) and scientific partners have now estimated the total geothermal probe potential in Baden-Württemberg in a study.
According to the study, if one geothermal probe is used per parcel of land, there is a technical heat potential of around 9.3 terawatt hours (TWh) per year. That is around 12% of the total heating requirement of residential buildings in the southwest: According to the state’s heat atlas, the heating requirement of residential buildings in Baden-Württemberg is a maximum of 80 TWh per year.
The amount of heat gained could therefore supply up to 300,000 residential buildings. There are around 2.5 million residential buildings in Baden-Württemberg. The theoretical heat potential with the maximum possible number of geothermal probes per parcel is even 34 TWh per year. Around 43% of the heating requirements of residential buildings in the southwest could be covered in this way.
Geothermal probes for municipal heat planning
The study shows the great potential of geothermal probes for the heat transition in the southwest. KEA-BW makes the data available to municipalities free of charge so that municipalities can determine the geothermal probe potential in their district. This applies both to the large district towns and urban districts, which are obliged to draw up and update a municipal heat plan, and to the smaller municipalities that voluntarily plan heat. Service companies that work on behalf of these municipalities also have access to the data.
KEA-BW concludes a user agreement with the municipalities or their service companies. Once this is signed, the State Energy Agency provides the data for the entire area of Baden-Württemberg. In it, the users undertake to use the data only for the purpose of creating or updating a municipal heat plan.
KEA-BW created the data in cooperation with the University of Groningen, the Institute for Building and Energy Systems IGE at the Biberach University of Applied Sciences and the State Office for Geology, Natural Resources and Mining (LGRB). Geodata was provided by the Baden-Württemberg State Office for Geoinformation and Rural Development (LGL), the Baden-Württemberg State Institute for the Environment (LUBW) and the LGRB.
What geothermal probes bring to the heat transition
Geothermal probes can make a significant contribution to the heat transition. They use the heat in the earth’s interior at a depth of up to one hundred meters and transport it upwards from there via a heat transfer medium. With this form of use of near-surface geothermal energy, temperatures of ten to 15 degrees Celsius can typically be used. Geothermal probes are mostly used on individual properties as a heat source for a heat pump. However, the climate-friendly heat is also fed into cold local heating networks. The temperature is raised to the level required for heating in winter using heat pumps in the individual buildings. Due to the low temperatures, the system can also be used for cooling on hot summer days.
Cold local heating is still a reliable supply variant that is implemented almost exclusively in new development areas. However, it definitely offers potential for efficient existing buildings in rural and urban areas. A second possibility is to provide the necessary temperature increase with a large central heat pump and to distribute it with a heating network. With this variant, less efficient buildings could also be supplied. ■
Those: KEA BW / ml
In context:
Geothermal heat pumps can cover 75% of the heat requirement
Many factors slow down ground source heat pumps
