How these “sand batteries” could solve our energy problems

Finnish engineers have installed the world’s first “sand battery”. It uses sand to store wind and solar energy in summer as heat, which can then be released in winter to heat homes and offices.

This winter is likely to be complicated for many European countries, especially those that are heavily dependent on gas Russian. This shortfall could be partially compensated by increasing the number of facilitiesrenewable energies. However, production is too variable to completely depend on it without also installing big batteriesusually at lithium, expensive to produce. A Finnish company may have found a solution low-tech with a seasonal battery based on sand.

Polar Night Energy has just completed its first commercial installation in the town of Kankaanpää. Its battery takes the form of a silo filled with sand from construction. When there is a surplus of electricity production, the surplus is used to heat the sand up to 500°C. This sand, perfectly ordinary, can preserve this heat During months. The battery, which is about four meters wide and seven meters high, contains about 100 tons of sand. It has a capacity of 8 MWh (megawatt hours) and a heating power of 100 kW (kilowatts).

A solution without hazardous products

This energy is not reconverted into electricity when demand increases because the yield is currently quite mediocre. On the other hand, stored heat can be retained until winter and transferred to water to heat the houses, offices and even the local swimming pool. It is a solution that does not use any matter dangerous, requires very little maintenance and can operate for decades.

The next step will be to create a much larger battery. Engineers said the next could be a thousand times bigger. According to the company, the internal temperature of the battery could reach up to 1,000°C, with a capacity of 20 GWh (gigawatt hours) and delivering a power of 100 MW (megawatts). It already offers huge benefits for winter heating, but if engineers can figure out how to convert heat back into electricity efficiently, the sand battery could revolutionize thegreen energy.