Geothermal exploration in Göttingen: 20 Years of multi-horizon targets and implementation barriers

Göttingen is located at the eastern margin of the of N-S trending Leinetal Graben, which developed within ~ 1500 m of Permian-Mesozoic cover rocks. Potential geothermal horizons for heat extraction and/or storage in medium-depth geothermal systems include Zechstein salt and dolomite layers, Middle Buntsandstein strata, and karstified Muschelkalk carbonates. Strategies for the geothermal exploitation of the meta-sedimentary rocks of the Variscan fold-and-thrust belt, which are expected to underlie the sedimentary cover, have been developed based on analogue studies in the Harz Mountains.

A multi-target approach is proposed for Göttingen, integrating both shallow and medium-deep geothermal systems, in coordination with existing surface heating and cooling infrastructure. Feasibility studies to date have relied primarily on detailed geological surface maps and two intersecting seismic lines, approximately 10 and 11 km in length, recorded in 2015. These seismic profiles supplement the very limited well data available for the sedimentary cover. The geological interpretation of the seismic data remains highly uncertain, however, because of the scarcity of well data, significant lithological thickness variations within the graben, and intense faulting and halokinesis in its central part. A scientific exploration well is essential as the next step to reduce exploration risk, particularly in terms of economic feasibility. Simultaneously, only optimally designed transformation strategies for energy supply and surface infrastructure will enable the successful implementation of multiple geothermal systems.