SAND BATTERIES BREAKTHROUGH IN STORING SOLAR AND WIND ENERGY

Solar energy stored in ‘sand batteries’ could help get Finns through the long cold winter, which is set to be even tougher after Russia stopped its gas and electricity supplies.

The new technology has been devised by young Finnish engineers Tommi Eronen and Markku Ylönen, founders of Polar Night Energy, but could be used worldwide.

Though a number of other research groups are testing the limits of sand as green energy storage, the pair are the first ones to successfully rig it to a commercial power station.

Around 100 tonnes of the fine stuff, piled high inside a silo, went live at a power plant in the southwestern town of Kankaanpää in late May – just as Putin cut the country off in retaliation for joining NATO.

“We were talking about how – if we had the liberty to design a community for ourselves – how could we solve the energy problem in such a confined environment?” Markku says of the company’s inspiration.

The sand inside the silo can store heat at around 500C for several months. Polar Night Energy

“Then quite quickly, especially here in the north, you run into the problem of energy storage if you’re trying to produce the energy as cleanly as possible.”

The friends started playing around with ideas, landing on sand as an affordable way to store the plentiful electricity generated when the sun is shining, or wind blowing at a high rate.


Finding a way to store these variable renewables is the crux of unleashing their full potential. Lithium batteries work well for specific applications, explains Markku, but aside from their environmental issues and expense, they cannot take in a huge amount of energy.

Grains of sand, it turns out, are surprisingly roomy when it comes to energy storage.