Feasibility study on the repurposing of the well doublet at the Groß Schönebeck research platform

The Groß Schönebeck site offers a unique opportunity to promote geothermal innovation in Germany via three distinct development pathways. One approach is an Enhanced Geothermal System (EGS), which involves repurposing an existing well (Gt GrSk 4/05 (A2)) for injection. However, challenges regarding fracture sustainability, scaling and long-term performance require further investigation before the economic viability can be assessed. A nearer-term alternative is a coaxial Deep Borehole Heat Exchanger (DBHE) system that leverages exceptional subsurface temperatures and existing well infrastructure. Simulations suggest a potential thermal power output of 500–750 kW over 30 years, provided insulation performance and well integrity are validated. A third pathway focuses on medium-depth hydrothermal resources within surrounding formations. This involves characterizing the reservoir, developing a tailored doublet and optimizing materials for hypersaline conditions. Critically, existing deep wells can be repurposed for comprehensive monitoring supporting the third pathway. The site's advantages: pre-existing and high-temperature deep wells; proximity to district heating networks; and a controlled research environment, can further facilitate adaptive investment. From near-term DBHE deployment to future EGS expansion, Groß Schönebeck offers a scalable solution for advancing geothermal energy in Germany. Further research focused on long-term performance and material optimization is essential to unlocking the site’s full potential.