Estimation of shallow geothermal potential to meet building heating demand on a regional scale

Abstract

Extracting shallow geothermal energy using borehole heat exchangers (BHEs) can help decarbonising the residential heating sector, particularly where no other low-carbon heating solutions are readily available. To assist urban planners and policy makers in developing carbon-neutral heating plans, the regional technical shallow geothermal potential must be known. Here, we calculate 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. We then link this technical geothermal potential to heating demand scenarios on a building block scale and the results show that, depending on the renovation status of the buildings, between 44% and 93% of all building blocks can be heated using only BHEs. This allows for a rapid identification of building blocks for which BHEs are not able to meet the heating demand and where other means of heat supply will be needed.