Hydrogeological Investigation and Techno-Economic Evaluation of a Geothermal Mine Water System

Abandoned mine infrastructures offer promising potential for subsurface thermal energy extraction and storage in urban environments. However, their integration into energy systems demands a thorough understanding of hydrogeological behavior and economic feasibility. In this study, we present a comprehensive investigation of a geothermal mine water system operating within an abandoned mine in Germany since 9 years. Our approach combines detailed field monitoring, advanced data-driven analysis, and techno-economic evaluation.

High-resolution, high-frequency measurements at the study site reveal dynamic interactions between mine water and surrounding groundwater. These data capture short-term fluctuations driven by recharge events and pressure propagation through interconnected voids and fractured rock. Combined with depth-resolved temperature profiles and in-situ video inspections of mine shafts using cameras and underwater rovers, we aim to gain a detailed understanding of hydraulic processes within the mine workings and their connection to the regional groundwater system.

To translate hydrogeological investigation into system planning and policy decisions, we analyze the sensitivity of the economic performance of the system to carbon pricing, integrating gained insights and operational experience with forward-looking economic modeling. Our results suggest that under the favorable geological and hydraulic conditions at the test site, mine-based geothermal systems can achieve levelized costs that are competitive with air-source heat pumps.

This integrated approach highlights the value of high-frequency field data, data-driven automated analysis, and economic modeling for assessing the viability of repurposing post-mining infrastructure for sustainable energy use.