A small municipality in Finland could soon be home to a big ol’ battery, and a pretty unusual one at that – it stores thermal energy in sand. It’s hoped this “sand battery” could increase the storage of renewable energy to meet year-round heating demands, and with it, help cut carbon emissions.
The battery is designed by startup Polar Night Energy and is due to be built over the next 13 months in Pornainen, Finland. Once constructed, the company estimates that it could lead to a reduction in yearly carbon dioxide emissions of nearly 70 percent. That’s largely due to the predicted complete elimination of oil use, and a roughly 60 percent reduction in the burning of woodchips.
So how will the people of Pornainen get their heat from the battery?
The sand battery itself will be a 13-meter-high (43 feet), 15-meter-wide (49 feet) silo filled with crushed soapstone – which conducts heat better than conventional sand – and heat transfer pipes. The plan is that, when excess electricity is produced from wind and solar sources, a process called resistive heating will be used to convert it to thermal energy.
This will heat up air, which is then circulated throughout the silo using the heat transfer pipes and in doing so, warms up the surrounding crushed soapstone. When conventional energy sources get a bit pricey, such as during the winter months, the hot air can then be discharged into the district’s heating system.
The battery being built in Pornainen is not the first of its kind; Polar Night Energy previously installed the world’s first fully working commercial sand battery in Kankaanpää, also in Finland, back in 2022.
However, this latest venture is set to be about 10 times larger, with a heating power of 1 megawatt and the capability to store up to 100 megawatt hours of thermal energy. That’s enough to meet the district’s week’s heat demand in the winter, and almost one month in the summer.
With the world looking to increase its capacity to store potentially limitless renewable energy, and being met by many expensive and environmentally impactful options, sand batteries like this one could represent a cheaper, lower impact alternative. It still comes with caveats though; the thermal energy it stores could be converted back to electricity, but this “has inherent losses, thus complicating the economical side,” according to Polar Night Energy.
The completion of this particular battery is a little while off yet, but there’s no shortage of alternative energy storage projects happening in the meantime – Finland is also set to see an abandoned mine turned into a giant gravity battery.
Source Link: World's Biggest Sand Battery Could Spell The End Of Oil For One Small Town
