The sand battery designed by the startup Polar Night Energy will be built over the next 13 months in Pornainen, Finland, to meet year-round heating demands.
Polar Night Energy is constructing the world’s largest sand battery in Finland. (Image: BBC).
Once completed, the company estimates that this new type of battery could help reduce annual carbon dioxide emissions by 70%. The sand battery consists of a 13-meter high and 15-meter wide container filled with crushed soapstone (which conducts heat better than regular sand) and heat transfer pipes. According to reports from IFL Science on March 11, the process known as resistive heating will be employed to convert surplus energy from wind and solar sources into thermal energy.
This process will heat the air, which will then circulate through the container via heat transfer pipes, warming the crushed soapstone surrounding it. When conventional energy sources become expensive, particularly during the winter months, the heated air can be introduced into the district’s heating system.
The sand battery being built in Pornainen is not the first of its kind. Previously, Polar Night Energy installed the world’s first fully operational commercial sand battery in Kankaanpää, Finland, in 2022. However, the latest version will be ten times larger, with a heating capacity of one megawatt and the ability to store up to 100 megawatt-hours of thermal energy, sufficient to meet the heating demands of the entire district for a week in winter and nearly a month in summer.
As the world seeks to enhance energy storage capabilities with various costly and environmentally impactful solutions, sand batteries like this could become a low-cost and less impactful alternative, according to Polar Night Energy. In addition to the sand battery project, Finland is also preparing to transform an abandoned mining site into a massive gravity battery.
