Polar Night Energy has built an industrial-scale sand battery in Pornainen for Loviisan Lämpö’s district heating network. The new sand battery delivers 1MW of thermal power and offers a storage capacity of 100MWh, making it 10 times larger than the Sand Battery launched in Kankaanpää in 2022.

The sand battery is expected to reduce annual CO₂-equivalent emissions from the local heating network by around 160 tons, cutting climate emissions in Pornainen’s district heating by nearly 70%.

The launch means the use of oil in the Pornainen’s heating network will be completely phased out, and the consumption of wood chips will decrease by approximately 60%. The existing biomass boiler will continue to serve as a backup and will support the sand battery during peak demand periods.

Developed by Polar Night Energy, the sand battery is a high-temperature thermal energy storage system that stores clean and affordable electricity as heat in sand or similar solid materials. It can be used to produce heat for both district heating networks and a wide range of industrial processes.

Energy storage plays a vital role in the energy transition, as the share of wind and solar power in the electricity grid increase and combustion-based energy production is phased down.

The sand battery stands about 13m tall and 15m wide, and it uses approximately 2,000 tonnes of crushed soapstone as its thermal storage medium. In summer, the sand battery can cover almost a month’s heat demand in Pornainen, and in winter, close to a week.