“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 mining 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 mining geology, hydrogeology, geochemistry, reservoir geomechanics, underground heat storage, solar energy, and district heating systems.

GeoSolar is funded by the EU 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 mining regions transform their industrial legacy into a sustainable energy future.