Polar Night Energy Builds Industrial-Scale Sand Battery in Pornainen

🌍 Polar Night Energy’s Industrial-Scale Sand Battery in Pornainen

Finnish cleantech company Polar Night Energy has launched a groundbreaking Sand Battery in Pornainen, integrated into Loviisan Lämpö’s district heating network. Delivering 1 MW of thermal power with a 100 MWh storage capacity, this installation is ten times larger than the pilot system in Kankaanpää (2022).

🔥 What It Means for Pornainen

By using sand as a heat storage medium, Loviisan Lämpö can cut emissions by nearly 70%, eliminate oil entirely, and reduce wood chip use by 60%. The system stores energy in 2,000 tonnes of crushed soapstone, a circular by-product of Tulikivi’s fireplace production. In summer, it covers almost a month’s heating demand; in winter, nearly a week.

“The Sand Battery allows us to drastically reduce emissions and improve reliability. It’s a major step toward our climate-neutral 2035 goal.” — Mikko Paajanen, CEO of Loviisan Lämpö

⚡ How It Works

The Sand Battery converts renewable electricity into high-temperature heat, stored in sand or similar granular solids. That heat is later transferred to district heating systems or industrial processes. With variable solar and wind generation, long-duration thermal storage like this balances the grid while supporting fossil-free energy.

🏗 A Collaborative Effort

The project relied on 40 subcontractors and 100+ workers over a year. Business Finland provided funding support, while Elisa Industriq optimized operations with an AI-driven solution to decide charging/discharging windows — maximizing both environmental and economic benefits.

🔄 Circular Economy in Action

Unlike lithium batteries, the Sand Battery relies on abundant, recyclable soapstone waste. This highlights how industrial side streams can be repurposed into climate solutions, accelerating the circular economy while reducing reliance on scarce raw materials.

🌐 A Step Toward Climate Neutrality

For Pornainen, the Sand Battery is more than heat storage — it’s energy independence. By integrating electricity and heat, Loviisan Lämpö and its partners show how local communities can pioneer the global energy transition toward carbon neutrality by 2035.

Learn more at Polar Night Energy.