Finland's sand battery helps store renewable heat in Pornainen
Sand battery Finland stores renewable heat for district heating and cuts emissions See how the world’s largest system reduces wood-chip use and backs cleaner energy
A town in southern Finland is using what is described as the world's largest commercial sand battery to help manage renewable energy's uneven supply. The facility in Pornainen stores heat in 2,000 metric tons of crushed soapstone and can provide district heating for nearly a month in summer or about a week in winter.
The project was developed by Polar Night Energy for local utility Loviisan Lämpö. According to the company, the system has cut emissions from the heating network by almost 70% and reduced woodchip use by about 60%, while a backup woodchip plant still covers peak demand.
The battery works by using electricity when wind or solar power is plentiful, heating the sand to high temperatures, and then releasing that stored heat later through heat exchangers. Supporters say the approach could help ease renewable intermittency and reduce reliance on fossil fuels, although scaling the technology remains a challenge.