We’ve previously written about how water batteries could help address the energy storage challenge facing the green energy transition. In Finland, however, some scientists are working on a much dryer power storage facility — a ‘sand battery’.
Solving the energy storage challenge
That’s right, at a small power plant in western Finland stands a sand-based battery that may solve the problem of year-round green energy supply. It works by heating sand in a silo with electricity made from wind and solar. The sand can store heat at around 500C (932F). That heat can later be used to warm up homes during times of high energy demand such as in winter.
The main feature of the battery storage technology is a dull grey silo that holds 100 tonnes of builder’s sand. Located in the town of Kankaanpää, the equipment represents the first commercial installation of a battery that uses sand. According to the young team of engineers behind it, the battery could help solve the energy storage problem in a cost-effective, low-impact way.
“Whenever there’s like this high surge of available green electricity, we want to be able to get it into the storage really quickly,” said Markku Ylönen, one of the two founders of Polar Night Energy, the company behind the product.
Storing energy by heating sand
The sand in the silo is heated using resistive heating, the same process used by electric fireplaces. The heated sand generates hot air which is circulated throughout the container with the help of a heat exchanger. The heated sand retains its temperature over long periods of time so the technology is very effective at keeping the sand at 500C (932F) for several months.
As such, when energy prices are high, the battery can be used to warm up water for the district heating system. The water can then be pumped around into homes in the area, as well as offices and even a local swimming pool.
The innovative technology is an opportunity to green up many industries, such as food and beverage since most of the process heat used by these comes from dirty sources such as fossil fuels.
