Finland inaugurates world’s largest 1 MW/100 MWh sand battery

Polar Night Energy has built an industrial-scale 1 MW/100 MWh Sand Battery in Pornainen, Finland, for Loviisan Lämpö’s district heating network.

The Sand Battery is projected to lower annual CO₂-equivalent emissions in Pornainen’s district heating network by about 160 tons, achieving a nearly 70% reduction in climate emissions. Its implementation eliminates oil use in the heating network and reduces wood chip consumption by around 60%, with the existing biomass boiler retained as a backup for peak demand. Developed by Polar Night Energy, the Sand Battery is a high-temperature thermal storage system that converts clean, cost-effective electricity into heat stored in sand or similar materials, suitable for district heating and various industrial applications.

Polar Night Energy served as the primary contractor, delivering the Sand Battery as a turnkey solution to Loviisan Lämpö. The battery, measuring roughly 13 meters tall and 15 meters wide, utilizes approximately 2,000 tonnes of crushed soapstone for thermal storage. It can meet nearly a month’s heating needs in Pornainen during summer and about a week in winter. Loviisan Lämpö is owned by CapMan Infra, a fund under CapMan, a private equity firm committed to being the most responsible investor in the Nordic region.

The Sand Battery enhances power grid stability, facilitating the expansion of wind and solar energy. Its substantial storage capacity enables electricity use optimization over days or weeks. The Pornainen Sand Battery’s optimization is managed by Elisa, a Finnish telecommunications and digital services company. The thermal storage medium, often sourced from manufacturing or mining by-products, reduces the need for virgin materials. For Loviisan Lämpö’s Sand Battery, the medium is crushed soapstone, a by-product from Tulikivi’s heat-retaining fireplace production, with the battery containing 2,000 tonnes of this material, equivalent to the weight of about 1,000 soapstone fireplaces.