A groundbreaking sand battery in Pornainen, Finland, is poised to transform energy storage and reduce carbon emissions. Developed by Polar Night Energy, this innovative solution uses sand to store excess thermal energy from renewable sources, such as solar and wind power.
The battery, set to become the world’s largest sand battery upon completion, will store up to 100 MWh of thermal energy. By eliminating oil from the district heating network, it is projected to slash emissions by nearly 70%.
The technology behind the sand battery is relatively simple yet highly effective. A tall tower filled with low-grade sand is charged with excess heat using resistive heating, generated through friction when an electrical current passes through the sand. This heat is then circulated and stored within the sand, ready to be released when needed.
Once operational, the sand battery will integrate seamlessly with the local heating network, providing sustainable and affordable energy to homes, businesses, and public facilities. In addition to reducing carbon emissions, it will contribute to Pornainen’s goal of achieving carbon neutrality.
The choice of sand as the storage medium offers several advantages, including affordability and widespread availability. Polar Night Energy has even sourced sustainable alternatives, such as crushed soapstone, to minimise environmental impact and promote circular economy principles.
With construction underway and testing expected to be completed within 13 months, the sand battery is on track to be operational by winter 2025. This ambitious project not only showcases Finland’s commitment to renewable energy but also highlights the potential of sand batteries to revolutionise energy storage worldwide.
This approach is similar to initiatives to store heat in salt tanks (Heatcubes developed by Norwegian Kyoto Group), bricks (pioneered by Rondo in California), concrete (by Swiss EnergyNest), steel (Germany’s Lumenion), gel (Plentigrade by Scotland’s Sunamp), compressed air (Cheesecake Energy), or super-cooled liquid air in a partnership between British company Highview and Danish Ørsted).
Sources
‘A very Finnish thing’: Big sand battery to store wind and solar energy using crushed soapstone, Euronews, 2024-03-13
Salt, air and bricks – could this be the future of energy storage?, The Guardian, 2024-04-01
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