It doesn’t appear like a lot, however Finland just lately flipped the swap on the world’s largest sand-based battery.
Yes, sand.
A sand battery is a sort of thermal power storage system that makes use of sand or crushed rock to retailer warmth. Electricity — usually from renewable sources — is used to warmth the sand. That saved warmth can later be used for varied ends, together with to heat buildings.
The economics are compelling, and it’s laborious to get any cheaper than the crushed soapstone now housed inside an insulated silo within the small city of Pornainen. The soapstone was principally trash — discarded from a Finnish hearth maker.
Though it may not be as visually spectacular as a big lithium-ion battery pack, the two,000 metric tons of pulverized rock contained in the 49-foot-wide silo guarantees to slash Pornainen’s carbon emissions, serving to the city eradicate pricey oil that presently helps energy the city’s district heating community.
Like many Scandinavian cities, Pornainen operates a central boiler that heats water for properties and buildings round city. Polar Night’s battery can retailer 1,000 megawatt-hours of warmth for weeks at a time, sufficient for every week’s value of heating within the chilly Finnish winter. From storage to restoration, solely about 10% to fifteen% of the warmth is misplaced, and the temperature on the outlet may be as much as 400°C.
The city’s district heating system additionally depends on burning wooden chips, and the sand battery will cut back that consumption by about 60%, based on Polar Night. Heat from the battery may additionally generate electrical energy, although the method would sacrifice some effectivity.
As renewables have gotten cheaper, curiosity in thermal batteries has grown. Beyond Polar Night, quite a few startups are pursuing thermal batteries. Scotland-based Sunamp is constructing one which depends on the identical materials that provides salt-and-vinegar potato chips their taste. Electrified Thermal Solutions, TechCrunch’s Startup Battlefield 2023 runner-up, has created a sort of brick that may produce warmth approaching 2,000°C. And Fourth Power is making graphite blocks that retailer electrical energy as 2,400°C warmth.
Pornainen’s battery is charged utilizing electrical energy from the grid, and its huge storage capability permits the operator to attract energy when it’s most cost-effective. Finland’s grid is usually renewables (43%) and nuclear (26%), that means its electrical energy is fairly clear. It’s additionally the most cost effective in Europe at just below €0.08 per kilowatt-hour — lower than half the EU common.
Polar Night didn’t disclose the challenge’s price, although the uncooked supplies are low cost and the construction itself isn’t notably advanced. A a lot smaller prototype constructed a number of years in the past price round $25 per kilowatt-hour of storage, the corporate estimated on the time. It’s possible the brand new model is cheaper. Lithium-ion batteries price round $115 per kilowatt-hour.
