Finland warms up the world’s largest sand battery, and the economics look appealing

It doesn’t look much like it, but Finland has recently overturned the world’s largest sand battery in the world.

Yes, sand.

A sand battery is a type of thermal energy storage system that uses sand or crushed rock to store heat. Electricity – generally from renewable sources – is used to heat the sand. This stored heat can later be used for various ends, including to heat buildings.

The economy is convincing, and it is difficult to obtain a little cheaper than the crushed soap stone which is now housed in an isolated silo in the small town of Pornainen. The soap stone was essentially garbage – thrown from a Finnish chimney manufacturer.

Although it is not as impressive visually as a large package of lithium-ion, the 2,000 metric tonnes of sprayed rock inside the 49-foot silo promises to reduce carbon emissions from Pornainen, helping the city eliminate the expensive oil which currently helps to supply the city district heating network.

Like many Scandinavian cities, Pornainen operates a central boiler that heats water for the houses and buildings in the city. The Polar Night battery can store 1,000 heat megawattheures for weeks at a time, enough for a week of heating in Finnish winter. From storage to recovery, only about 10% to 15% of heat is lost and the temperature at the outlet can be up to 400 ° C.

According to Polar Night, the city’s district heating system is also based on wood shavings, and the sand battery will reduce this consumption by around 60%, according to Polar Night. The heat of the battery could also produce electricity, although the process sacrifices a certain efficiency.

While renewable energies have become cheaper, interest in thermal batteries has increased. Beyond the polar night, many startups pursue thermal batteries. Sunamp based in Scotland is Building one This is based on the same material that gives potato poutilles of salt and vinegar their flavor. Electrified thermal solutions, Startup Battlefield 2023 from Techcrunch finalisthas created a type of brick that can produce heat Approaching 2,000 ° C. and the fourth power makes graphite blocks which store electricity Like 2,400 ° C heat.

Pornainen’s battery is loaded using network electricity, and its massive storage capacity allows the operator to pull energy when it is the cheapest. Finland’s grid is mainly renewable energies (43%) and nuclear (26%), which means that its electricity is quite clean. It is also the The cheapest in Europe Just under € 0.08 per kilowatt hour – less than half of the EU average.

Polar Night has not disclosed the cost of the project, although the raw materials are cheap and the structure itself is not particularly complex. A much smaller prototype built a few years ago $ 25 per kilowatt-hour storage, the company estimated at the time. It is likely that the new version is cheaper. Lithium-ion batteries cost around $ 115 per kilowatt-hour.