Finland has taken a major step toward sustainable energy solutions with the construction of the world’s largest sand battery. Developed by Polar Night Energy, this innovative system delivers 1 MW of thermal power and offers a storage capacity of 100 MWh.
The project, located in Pornainen, was built for the Loviisan Lämpö power station. Its main goal is to reduce annual CO₂ emissions by storing clean and affordable electricity as heat, helping to stabilize the grid and improve the use of renewable energy.
How the Sand Battery Works
The sand battery is a high-temperature thermal energy storage system. It stores electricity as heat in sand or similar solid materials, which can later be used to provide heating for homes, businesses, and industry.

The system stands about 13 meters tall and 15 meters wide, filled with 2,000 tonnes of crushed soapstone. This storage medium can retain heat for months with minimal loss, making it an efficient and low-cost solution for long-term energy storage.
Building the Sand Battery
The construction took around a year to complete and involved 40 subcontractors and more than 100 workers. The collaborative effort highlights Finland’s commitment to renewable energy and innovation in sustainable infrastructure.
Why It Matters
Unlike traditional batteries that store electricity directly, the sand battery converts electricity into heat, offering a cheaper, scalable, and sustainable way to store energy for longer durations. It is especially valuable in regions with strong renewable energy generation, such as wind and solar, where supply can fluctuate.
Looking Ahead
As countries worldwide search for reliable energy storage solutions, Finland’s sand battery stands as a pioneering example of innovation. If successful, this technology could be scaled up globally, supporting the transition to cleaner energy systems.
Source: Polar Night Energy