Finland warms the world’s largest sand battery, making economics appealing

It’s not very visible, but Finland recently flipped the switch on the world’s largest sand-based battery.

Yes, sand.

Sand batteries are a type of thermal energy storage system that uses sand or crushed rock to store heat. Electricity – Electricity from renewable sources is usually used to heat sand. The stored heat can be used later on various edges, including warm buildings.

Economics is persuasive and it is difficult to get cheaper than the soapstones now crushed into insulated silos in the small town of Pornen. Soapstones are essentially garbage and were dumped by a Finnish fireplace manufacturer.

While it may not be as impressive as the large lithium-ion battery pack, the 2,000-meter crushed rock within a 49-foot-wide silo promises to reduce Pornen’s carbon emissions and helps eliminate the expensive oil that powers the town’s district heating network.

Like many Scandinavian towns, Pornen operates a central boiler that heats water for homes and buildings around the town. The Polar Night battery can store 1,000 megawatt hours of heat at once for a week. From storage to recovery, only about 10% to 15% of the heat is lost, with the outlet temperature reaching 400 degrees Celsius.

According to Polar Night, the town’s district heating system also relies on burning wood chips, and sand batteries reduce its consumption by about 60%. Heat from the battery can also generate electricity, but the process sacrifices some efficiency.

As renewable energy gets cheaper, interest in thermal batteries is growing. Beyond Polar Night, many startups are pursuing thermal batteries. Sunamp, based in Scotland Build one It relies on the same ingredients that you taste salt and poisonous potato chips. TechCrunch Startup Battlefield 2023, Electric Heat Solutions runner-upI created a kind of brick that can be Generates heat It’s approaching 2,000 degrees Celsius. And the fourth power is creating a graphite block Store electricity Heat of 2,400 degrees Celsius.

Pornainen’s batteries are charged using electricity from the grid, and their large storage capacity allows operators to draw power when they are at their lowest. The Finland grid is Mainly renewable energy (43%) and the nucleus (26%), that is, its electricity is pretty clean. That too Cheapest in Europe It is just under 0.08 euros per kilowatt-hour, less than half the EU average.

Polar Night did not disclose the cost of the project, but the raw materials are cheap and the structure itself is not particularly complicated. A much smaller prototype was built a few years ago, which costly $25 per kilowatt hour In the case of storage, the company estimated it at the time. The newer version is probably cheaper. Lithium-ion batteries cost more $115 per kilowatt-hour.