‘A very Finnish thing’: Big sand battery to store wind and solar energy using crushed soapstone

A huge sand battery is set to slash the carbon emissions of a Finnish town.

The industrial-scale storage unit in Pornainen, southern Finland, will be the world’s biggest sand battery when it comes online within a couple of years.

Capable of storing 100 MWh of thermal energy from solar and wind sources, it will enable residents to eliminate oil from their district heating network, helping to cut emissions by nearly 70 per cent.

"It's exciting to build a large-scale thermal energy storage, which will also act as a primary production plant in Pornainen's district heating network,” says Liisa Naskali, COO at Polar Night Energy, the company behind the innovation.

“This is a significant step in scaling up the sand battery technology.”

The new 1 MW sand battery has a precursor. In May 2022, Polar Night Energy rigged a smaller design to a power station in Kankaanpää town.

Launched just as Russia cut off gas supplies in retaliation for Finland joining NATO, the project was a timely example of how renewable energy could be harnessed in a new way.

Euronews Green previously spoke to the young Finnish founders, Tommi Eronen and Markku Ylönen, who engineered the technology.

“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 said of the inspiration behind Polar Night Energy in 2018.

“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 the wind blowing at a high rate.

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