Heating Finland’s cities is becoming more sustainable thanks to sand. Finnish startup Polar Night Energy has developed a battery that uses sand to trap and store energy from solar and wind electricity. The battery is a high-energy storage facility located in Kankaanpää and is fed power from the grid whenever excess electricity is available. Warming up to 600℃, the system traps the heat until it’s needed, when it can be released as either hot water, steam, or air.
Sand is the second most exploited natural resource after water and its emissions-heavy mining is highly damaging to local ecosystems. Polar Night Energy has stated that it uses high-density sand, which is only sourced from abundant areas and cannot be used in construction.
So far, the sand battery is providing a local district heating network, heating homes and businesses, as well as a municipal swimming pool. Scaling up, a similar sand battery will be installed in the city of Pornaien in a recent agreement between Polar Night Energy and district heating company Loviisan Lämpö.
