In the heart of Poland, a groundbreaking concept is taking shape that could revolutionize how we store and utilize renewable energy. Kamil Szewerda, a researcher at the KOMAG Institute of Mining Technology in Gliwice, is leading a team that proposes transforming decommissioned underground mine workings into high-temperature sand thermal energy storage systems. This innovative approach, detailed in a recent study published in the journal Applied Sciences, could address some of the most pressing challenges in the energy sector, from balancing power grids to reducing greenhouse gas emissions.
The idea is simple yet ingenious: use the vast, abandoned underground spaces of former mines to store thermal energy generated by renewable sources like solar panels and wind turbines. During the summer, when energy production often exceeds demand, this excess energy can be converted into heat and stored in sand-filled chambers. Then, during the winter, when heating demand is high, the stored heat can be released, providing a clean and efficient source of energy.
“Our concept leverages the existing infrastructure of old mines, which are often located near urban areas, making them ideal for supplying heat to public buildings and residential areas,” Szewerda explains. “This not only reduces heating costs but also significantly cuts down on greenhouse gas emissions and air pollution.”
The potential commercial impacts of this research are substantial. As Europe pushes towards decarbonization and the adoption of the Green Deal policy, the need for efficient energy storage solutions is more critical than ever. The intermittent nature of renewable energy sources like solar and wind makes energy storage a key component in ensuring a stable power supply. By converting excess energy into thermal storage, this system can help balance the grid, reducing the need for costly and polluting backup power sources.
Moreover, the use of sand as a storage medium offers several advantages. Sand has a high heat capacity and can be heated to temperatures well above the boiling point of water, making it an efficient and space-saving storage solution. “Sand is a durable, inexpensive material that can store heat at high temperatures for extended periods,” Szewerda notes. “This makes it an ideal candidate for seasonal thermal energy storage.”
The concept is not just theoretical. Finland has already implemented a similar system, with a commercial “sand battery” in operation. This installation heats homes, offices, and even a public swimming pool using thermal energy stored in sand. The success of this project underscores the viability of the approach and its potential for widespread adoption.
The research by Szewerda and his team, published in Applied Sciences, outlines three variants of thermal energy storage facilities that can be built in decommissioned mine workings. These range from small-scale demonstrators to large-scale systems designed to meet the heating needs of entire communities. The study also addresses technical aspects such as insulation methods, heat exchanger design, and the optimization of sand storage systems.
As the energy sector continues to evolve, the integration of such innovative storage solutions could play a pivotal role in achieving a sustainable and reliable energy future. The work by Szewerda and his colleagues at the KOMAG Institute of Mining Technology represents a significant step forward in this direction, offering a practical and environmentally friendly solution to one of the most pressing challenges in modern energy management. The concept of repurposing old mine workings for thermal energy storage not only provides a commercial opportunity but also aligns with the broader goals of decarbonization and sustainable development. As the world looks for ways to balance the grid and reduce emissions, this research could shape the future of energy storage and pave the way for a cleaner, more efficient energy landscape.
