- Polar Night Energy has built an industrial-scale Sand Battery in Pornainen for Loviisan Lämpö’s district heating network in Finland.
- The new Sand Battery delivers 1 MW of thermal power and offers a storage capacity of 100 MWh, making it ten times larger than the Sand Battery launched in Kankaanpää in 2022.
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.
Polar Night Energy acted as the main contractor for the project and delivered the Sand Battery as a turnkey solution to Loviisan Lämpö. The construction took about a year and involved around 40 subcontractors and over 100 workers.
The Sand Battery stands about 13 meters tall and 15 meters 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. The project received energy aid for new technology from Business Finland.
A key part of the Sand Battery’s profitability lies in optimising its operation according to electricity prices and Finland’s grid operator Fingrid’s reserve markets. In doing so, the Sand Battery also supports power grid stability, an essential enabler of the rapid growth of wind and solar energy. Thanks to its large storage capacity, the system allows electricity usage to be optimised over several days or even weeks. The optimisation of the Pornainen Sand Battery is handled by Elisa, a Finnish telecommunications and digital software services company.
Author: Bryan Groenendaal
