In July 2022, Finland introduced a new way to store energy. A company called Polar Night Energy, along with local utility Vatajankoski, built the first commercial sand battery in the town of Kankaanpää. The battery uses sand to store heat. It is kept inside a 7-meter-high steel tank, filled with around 100 tons of sand. When extra solar or wind power is available, the battery heats air to about 600°C. The hot air warms the sand. Later, the heat is used in the town’s district heating system.
This sand battery provides 100 kilowatts of heating. It can store up to 8 megawatt-hours (MWh) of thermal energy. Unlike typical batteries that store electricity, these store heat. This makes it useful in places with long winters.
A second sand battery is being built in Pornainen, a town in southern Finland. It will use crushed soapstone instead of sand. It will store 100 MWh of energy and help reduce oil use for heating by more than 60%. The battery will be ready in 2025.
Sand batteries do not use chemicals. They don’t contain rare earth metals or moving parts. This makes them cheaper to maintain and safer for the environment.
In the Gulf, such systems have not been used yet. Saudi Arabia and the UAE are using large lithium-ion battery projects to store solar energy. Saudi’s Red Sea Project has a 1,000 MWh battery. In the UAE, a 5-gigawatt solar project includes large-scale batteries.
However, researchers in the UAE have tested desert sand and found it can hold heat at temperatures up to 1,000°C. This means the material is ready for use in the region.
If sand batteries are adapted to cooling instead of heating, they could be used in Gulf cities. They may help store excess solar energy for night-time use in air conditioning or be linked with solar thermal plants.
