In Finland, a thermal battery with a capacity of 100 MWh on soapstone will undergo winter testing

At the end of October, Finnish startup Polar Night Energy completed filling a thermal storage tank with 2,000 tons of crushed soapstone. The battery will store up to 100 MWh of thermal energy with a peak power output of 1 MW. This capacity is enough to heat a small town for a week in winter and for a month to heat water in summer. Commissioning will take place in 2025. Tests will begin in a month or a little later.

Image source: Polar Night Energy

The start of construction of a large-scale heat storage facility for excess energy production from solar and wind installations in the region was announced in early 2024. Previously, Polar Night Energy, using the example of a pilot plant with a power of 100 kW and a capacity of 8 MWh, showed that the idea of ​​storing heat in heated sand for later use is quite workable and quite effective.

To implement a large-scale project, an agreement was concluded with the Porninen community in southern Finland. The project involved filling a thermal storage bunker with a diameter of 15 m and a height of 13 m with 2000 tons of sand. More precisely, sand was used in a pilot project. For a large-scale project, a more heat-intensive material was chosen and, in combination, a waste product from one of the local companies – soapstone, which is also called soapstone. This material is used by Tulikivi for lining fireplaces and sauna stoves. The use of industrial waste for a heat accumulator is the highest aerobatics in the field of circular economy, and the Finns were at their best in this matter.

Since the main part of the work has been completed and only the installation of external components remains, the work will soon move on to the area of ​​testing the drive under winter operating conditions. It is expected that a fully charged thermal accumulator will be able to supply heat to the homes of citizens in Lämpö County for a week. The storage device will be connected to the centralized heating system and will be able to heat up to 5 thousand citizens. Commissioning of the facility is expected later in 2025 based on test results.