Work is underway on a 100MWh thermal energy storage project in Finland, using the same ‘Sand Battery’ technology as a 8MWh system that came online in 2022.
The project is being built for district network heating operator Loviisan Lämpö at a location in Pornainen, near Helsinki, and will supply thermal energy for Loviisan’s network.
The 13×15 metre structure has already been filled with 2,000 tons of crushed soapstone from Tulikivi, a company that manufactures heat retaining fireplaces. Soapstone is a byproduct of that manufacturing and has good heat retention properties.
The thermal energy storage system works by heating a storage medium – which can be sand, soapstone or other sand-like materials – using electricity, and then retaining and discharging that heat for industrial or heating use. The technology provider is Polar Night Energy, and the system’s capacity is 1MW/100MWh, making it a 100-hour system.
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This is the second major project to be revealed by Polar Night Energy, following a 100kW/8MWh project that came online at the site of a power plant operated by utility Vatajankoski in June 2022.
Various installation works for the larger system in Pornainen are currently away, following the completion of filling last month, and testing of the project will begin in winter for commissioning in 2025.
“The Sand Battery will significantly reduce the combustion-based energy used in our district heating network, and the collaboration with Tulikivi has added a valuable circular economy aspect to this project,” said Loviisan Lämpö CEO Mikko Paajanen.
Polar Night Energy CEO Tommi Eronen added: “The filling process went even better than we expected, and everything was completed on schedule. We implemented some unique solutions to accommodate the material properties and learned a lot in the process. Working with Tulikivi has been a very positive experience.”
The project received support from Business Finland, the country’s official government agency for trade and investment promotion.
Loviisan Lämpö supplies heating to Loviisa, Pukkila, Pornainen, Pyhtää Siltakylä, the Pyhtää village centre, and Lappohja.
