“Turning the legacy of coal into the energy of tomorrow.”

GeoSolar brings mine-water geothermal and solar-thermal research to the next level by developing a unique energy storage concept for Europe’s coal regions.

The project seeks to answer a central question: How can end-of-life and abandoned coal mines be transformed into large-scale thermal batteries that store solar heat in summer and deliver clean, high-temperature district heating in winter?

The project is bringing together expertise in geological surveying, groundwater dynamics, water chemistry, solar-thermal engineering, underground heat storage, and district heating systems.

GeoSolar is co-funded by the Research Fund for Coal and Steel (RFCS) and delivered by a European consortium working with regional partners in Poland and Slovenia. The project contributes directly to the just transition, helping coal regions convert their industrial legacy into a sustainable energy future.