The Finnish town of Pornainen has just commissioned the world’s largest sand thermal storage system. It is a sand battery developed by Polar Night Energy, which is already operating as the main heating source for the Loviisan Lämpö district heating network.
The world’s largest sand battery
Thanks to this system, Finland is taking a key step in its transition to cleaner energy. The sand battery has an output of 1 megawatt and a storage capacity of 100 megawatt-hours.
These numbers not only double in scale the previous projects, but also make it possible to reduce CO₂ emissions from the city’s heating system by almost 70%, equivalent to 160 tons per year.
This battery reduces 70% CO₂ emissions. Source: Polar Night Energy
The device works by storing electricity from renewable sources in the form of heat inside some 2,000 tons of recycled soapstone. This crushed stone, a by-product of Finnish manufacturer Tulikivi, is heated to high temperatures that are then used to supply the thermal demand of residential, municipal and educational buildings.
During the summer, it can hold the net for almost a month. In winter, it covers a full week. Its integration also makes it possible to completely eliminate the use of oil and reduce biomass consumption by 60%, while maintaining the existing boiler as a backup.
Artificial intelligence and circular economy
Battery operation and charging are optimized thanks to an artificial intelligence solution artificial intelligence developed by the company Elisa, which automatically identifies the moments of lowest electricity cost. This, in addition to stabilizing the power grid in collaboration with Fingrid, turns the battery into a source of revenue and savings for Loviisan Lämpö.
The implementation of the system was supported by Business Finland as part of the promotion of clean technologies. At the technical level, more than 100 workers and 40 subcontractors participated under the direction of Polar Night Energy, which is already preparing new developments to scale this technology to industrial processes and new territories.
A commitment to sustainability
The battery is not just a technical component: it represents a concrete commitment to the circular economy and the integration of electric and thermal sectors. CapMan Infra, the fund that owns Loviisan Lämpö, sees this system as a strategic investment because of its potential to replace fossil fuels, participate in energy markets and adapt to different industries.
From the municipality’s perspective, the project also aligns with climate objectives. Key buildings in Pornainen already benefit from the new system, and the experience is expected to serve as a replicable example for other regions with cold climates and district heat networks.
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Source and photo: Polar Night Energy
