The world’s largest sand battery was officially inaugurated on 25 August in Pornainen, Finland.
Developed by Polar Night Energy and delivered as a turnkey solution to Loviisan Lämpö, the high-temperature thermal energy storage system is now the main production plant for the local district heating network.
The 1 MW/100 MWh battery stores clean electricity as heat in sand, enabling carbon-free heating and grid flexibility. In its first months of operation, it has exceeded guaranteed efficiency targets and reduced emissions from the Pornainen district heating network by around 70%. The previous woodchip plant has remained offline throughout the summer.
“A couple of years ago, we started considering how to take district heating in Pornainen to the next level. It would have been easy to simply replace the old woodchip power plant with a new one of the same kind, but that didn’t align with our goals. We evaluated every possible alternative, and the Sand Battery proved to be the best option,” said Mikko Paajanen, CEO of Loviisan Lämpö.
The sand battery inauguration was led by Finnish Minister of the Environment and Climate, Sari Multala. The municipality has supported the project from the outset, with key public buildings connected to the heating network.
CapMan Infra, owner of Loviisan Lämpö, sees commercial and strategic value in sand-based storage. “This is a concrete example of a cost-efficient and sustainable investment. And if it works here, it will work anywhere,” said Sauli Antila, Investment Director at CapMan Infra.
Reserve market operations are managed by Elisa Industriq using AI-driven optimisation, while Polar Night Energy is preparing additional large-scale thermal storage projects.
Image: CEO of Polar Night Energy Tommi Eronen, Minister Sari Multala and CEO of Loviisan Lämpö Mikko Paajanen.
