Finnish 100 MWh sand battery is operational

Finnish district heating company Loviisan Lämpö has announced “the world’s largest sand battery” is now operational, in southern Finland.

Loviisan Lämpö, owned by Finnish private equity company CapMan, has commissioned the 1 MW/100 MWh project from compatriot startup Polar Night Energy to supply up to a week’s district heating in the municipality of Pornainen – and up to a month’s worth in summer.

The local school, town hall, and library are among the facilities which will benefit from heat transmitted throughout Loviisan Lämpö’s network from the 2,000 tons of crushed soapstone which will be used to store heat generated by grid electricity during times of excess generation.

Announcing commissioning of the Business Finland-backed project, Loviisan Lämpö said the district heating network would see a 70% reduction in carbon emissions – the equivalent of around 160 tons per year – thanks to the end of oil use for heating and to a 60% reduction in the volume of wood chips used in a biomass boiler. The boiler will be retained as a backup power supply and for use during periods of peak heating demand.

To complete the circular economy approach, the project did not require any virgin soapstone as it instead used waste from the operations of Finnish heat retaining fireplace manufacturer Tulikivi. The soapstone used in the sand battery is from the equivalent of 1,000 fireplaces.

“Combustion is not a sustainable option for the climate or the environment,” said Polar Night Energy Chief Operating Officer Liisa Naskali, in a press release issued to announce commissioning of the site. “This project is a powerful example that effective solutions for mitigating climate change do exist. Loviisan Lämpö is a great example of a company bold enough to invest in new technologies.”

With construction having taken around a year and involved 40 subcontractors and more than 100 workers, the sand battery will also reinforce the network of national grid company Fingrid by participating in its energy reserve markets. To maximize revenue, the battery will be optimized by Finnish company Elisa.

Project developer Polar Night Energy in May announced plans for a pilot sand battery project in Valkeakoski, also in southern Finland, which would be able to generate electricity from stored heat in a “power-to-heat-to-power” site which is due online in 2027.