Polar Night Energy, a Finnish startup specializing in high-temperature thermal energy storage solutions for wind and solar power, is set to begin testing its innovative “Sand Battery” in Pornainen this winter. The company plans to commission the system by next year.
The Sand Battery stores renewable electricity in the form of heat within sand or similar materials, using crushed soapstone as the storage medium.
This soapstone, a by-product from the fireplace manufacturing process by local company Tulikivi, is being used to build the storage system. The facility is being developed to supply thermal energy for Loviisan Lämpö, a district heating company serving the local area.
Construction is progressing according to plan, with 2,000 tonnes of soapstone already added to the site by the end of October. Once operational, the Sand Battery will run entirely on electricity, providing a primary production source for the district heating network in Pornainen. It will have a power output of 1 MW and a storage capacity of 100 MWh.
Mikko Paajanen, CEO of Loviisan Lämpö, emphasized the environmental benefits, stating, “The Sand Battery will significantly reduce the combustion-based energy used in our district heating network, and the collaboration with Tulikivi has added a valuable circular economy aspect to this project.” The initiative represents a step forward in integrating renewable energy into district heating systems and reducing reliance on fossil fuels.
