Finland is the first country to use sand batteries. A new type of battery that allows store energy for monthsas described by the BBC, who has been able to visit the facilities of the company Polar Night Energy.
The problem with solar or wind energy is that its capture does not always coincide with its use. This is why energy storage systems are so important. To be able to retain this energy and use it when it is best for you. Now these Finnish researchers have created a commercial solution that can store energy for months using a material as cheap as sand.
100 tons of sand at 500ºC to store energy
Instead of moving electrons, sand batteries use resistive heating to increase the air temperature. This is then transferred to the sand through a heat exchanger. Under this system, a large pile of sand can act for all practical purposes like a battery.
In this case the size is relevant, with dimensions of almost 7 meters high. Polar Night Energy has built warehouses with about 100 tons of sand that reaches up to 500 degrees Celsius. The benefit is that this large “battery” allows energy to be stored for months with a 99% efficiencywhich would make it an interesting long-term storage system.
The nominal power of this system is 100 kW, with a total capacity of 8MWh of energy. As described by Polar Night Energy, they have the ability to increase capacity up to 20 gigawatt hours.
The first sand battery has been built in the town of Kankaanpää, in western Finland. The cost of building these warehouses has not been described, but the idea that sand is a much cheaper material than lithium is promoted. With the added advantage that any sand works.
As the company explains, the cost is approximately 10 euros per kilowatt hourwhile once built maintenance is minimal.
On the other hand, it is found that Starting up this system requires a large amount of energy.. Depending on how much interest there is in retaining energy for months, it would be necessary to do calculations to see if it is of interest. Possible applications are industries or buildings for which it is desired to maintain constant energy.
Image | Mehdi MeSSrro