Edinburgh-based company Gravitricity has announced its plans to develop underground gravity energy storage projects for deep mine operators in Slovenia, Germany, the Czech Republic, and Finland. This innovative approach repurposes end-of-life mine shafts, which would otherwise face expensive infilling and decommissioning costs.
Gravitricity’s energy storage system, known as GraviStore, utilizes heavy weights—up to 12,000 tonnes—suspended in deep shafts by cables attached to winches. During periods of excess electricity, such as on windy days, these weights are winched to the top of the shaft, ready to generate power when needed. The weights can be released in less than a second, with the winches acting as generators to produce electricity either in a quick burst or more gradually, depending on demand.
The company highlighted that GraviStore offers many advantages similar to pumped storage hydro and lithium-ion batteries, but without the performance degradation that affects batteries over time. This system can operate for decades with consistent efficiency.
Gravitricity’s current clients include the Velenje coal mine in Slovenia, owned by the government-run Premogovnik Velenje; First Quantum Minerals’ Pyhäsalmi mine in Finland, Europe’s deepest zinc and copper mine; the former Darkov mine in the Czech Republic, managed by the state enterprise DIAMO; and the Geiger Group’s Grube Teutschenthal mine in Germany.
“Gravity energy storage presents a powerful green opportunity for mine operators, extending the life of mines beyond material extraction,” said Martin Wright, founder and executive chairman of Gravitricity. “This alternative to decommissioning provides economic and employment opportunities in communities facing the decline of traditional jobs. Our engagements with mine operators demonstrate significant interest in our technology, and we are working with both mine owners and public sector organizations to transform these plans into operational realities.”
Gravitricity has already demonstrated its GraviStore technology with a 250kW above-ground prototype, successfully raising and lowering two 25-tonne weights to generate power and verify the system’s rapid response capabilities. The £1-million, 12-meter-high test rig proved the system can achieve full power in less than a second, making it highly valuable for frequency response and backup power markets, with the flexibility to adjust power output based on demand.
