Johannes Miocic, Marc Krecher

Extracting shallow geothermal energy using borehole heat exchangers (BHEs) can help decarbonising the residential heating sector. To assist urban planers and policy makers in developing carbon-neutral heating plans the regional technical shallow geothermal potential must be analysed. Here, we propose a methodology to estimate the technical geothermal potential of BHE fields on a regional scale while taking potential thermal interference between BHEs, geological conditions, as well as space available for BHE installation into account. The number of BHEs placed is maximized and heat extraction rate from each BHE is optimized taking regional regulations into account. When the methodology is applied to the German state of Baden-Württemberg on a building-block scale, results suggest an annual technical potential of 33.5 TWh. This technical geothermal potential is then linked to heating demand scenarios per building block and the results show that, depending on the renovation status of the buildings, between 44 % and 93 % of all building blocks can heated using only BHEs. This allows for the identification of building blocks in which BHEs are not able to meet the heating demand and where other means of heat supply will be needed.