Finnish Metropolis Inaugurates 1 MW/100 MWh Sand Battery

August 31, 2025

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There are extra methods to retailer power than simply utilizing batteries. Some are utilizing hearth bricks, significantly for course of warmth for industries that depend on excessive warmth in manufacturing. Others suggest an association of huge concrete blocks that transfer up and down just like the weights of a large grandfather clock, changing kinetic power to potential power and again once more. In Finland, two intrepid engineers started experimenting with a sand battery just a few years in the past.

As we reported when the primary prototype was unveiled three years in the past, the concept of a sand battery started with two Finnish engineers, Markku Ylönen and Tommi Eronen. The idea is simplicity itself. Make a extremely huge pile of sand. Warmth it with extra renewable electrical energy to round 500°C (932°F), then use that warmth later to warmth properties, factories, even swimming swimming pools. They are saying the sand can keep scorching for 3 months or extra. The pair have based Polar Evening Power, which constructed a prototype consisting of 100 tons of sand inside what appears like a silo within the city of Kankaanpää.

Many Individuals are unfamiliar with the idea of district heating, however it’s extensively utilized in different counties, particularly in Scandinavia the place protecting colleges, municipal buildings, arenas, factories, and houses heat in winter is a problem.

Loviisan Lämpö is a Finnish district heating firm that provides district heating to prospects in Loviisa, Pukkila, Pornainen, and Pyhtää. It has collaborated with Polar Evening on a brand new sand battery — one that’s a lot bigger than the prototype — which started working within the metropolis of Pornainen in southern Finland this month, the place it’s anticipated to cut back carbon emissions from district heating by 70 p.c.

Beforehand, nearly all of warmth wanted for the system got here from burning oil, however that has now been fully eradicated. The system will proceed to burn wooden chips to complement the sand battery. Wooden chips are at the very least carbon impartial, though not a great answer because it takes years for bushes to develop however solely minutes for the chips to burn.

On the commissioning ceremony for the brand new battery, Mikko Paajanen, CEO of Loviisan Lämpö, stated, “A few years in the past, we began contemplating how one can take district heating in Pornainen to the subsequent degree. It might have been simple to easily change the outdated wooden chip energy plant with a brand new one of many identical form, however that didn’t align with our targets. We evaluated each attainable various, and the Sand Battery proved to be the most suitable choice.”

The battery is a 42 foot tall, 50 foot vast metal cylinder crammed with 2,000 tons of crushed stone. In response to Quick Firm, when further renewable electrical energy is on the market, the system makes use of it to warmth up the crushed stone, the place it’s saved till wanted. Then the warmth from the battery travels to different buildings by means of a system of pipes crammed with scorching water. Every constructing has its personal tools to distribute the warmth to radiators, flooring heaters, or different heating units.

“We now have already learnt that our system has much more potential than we initially calculated. It’s been a constructive shock,” stated Ylönen after the prototype was positioned in service. “Each time there’s a excessive surge of accessible inexperienced electrical energy, we would like to have the ability to get it into the storage actually rapidly.” The necessity to use power extra properly was pushed dwelling for Finns after Russia stopped offering electrical energy, methane, and oil to Finland when it voted to affix NATO. Finland and Russia share a standard border.

Sand Battery Is Easy & Environment friendly

The sand battery is simplicity itself. “We simply warmth air and [circulate it] by means of sand,” says Liisa Naskali, COO of Polar Evening Power. However supplies apart from sand can be utilized. The brand new battery truly makes use of crushed soapstone chips from a neighborhood hearth producer. Sand, or different materials crushed into sand-size particles, has the power to retailer warmth for weeks. Not like another batteries, the system doesn’t depend on chemical substances, doesn’t degrade, and received’t catch on hearth. In operation, the sand battery has demonstrated a spherical journey effectivity of 90 p.c.

Contained in the metal tank, a warmth exchanger and a closed loop system are used to flow into the warmth. Software program runs heaters when electrical energy costs are low. To this point this summer season, the district heating operator has paid solely about 10 p.c of the common worth of electrical energy as a result of heating the system solely occurred at optimum instances. That helps make the know-how value aggressive, though the preliminary set up value is pretty excessive.

Polar Evening is now in talks with different district heating corporations and manufacturing unit homeowners with a necessity for top temperature course of warmth. For the corporate, the challenge in Pornainen is a crucial proof level. “That is actually vital for us as a result of now we will present that this actually works,” a spokesperson for Polar Evening stated.

Funding Alternatives

Polar Evening and its companions see a shiny monetary future for sand batteries as a result of they will take part in electrical energy reserve markets, scale back dependence on single power sources in warmth manufacturing, and function a wonderful instance of sector integration between electrical energy and warmth.

“For us, the sand battery is a good business funding, however we additionally wished to boldly assist an progressive answer that advantages prospects, the municipality, and the whole electrical energy market. This can be a concrete instance of a price environment friendly and sustainable funding. If it really works right here, it should work wherever,” stated Sauli Antila, the funding director at CapMan Infra, the company proprietor of Loviisan Lämpö.

The profitability of the sand battery is predicated on charging it in line with electrical energy costs and Fingrid’s reserve markets. Its massive storage capability permits balancing the electrical energy grid and optimizing consumption over a number of days and even weeks. The reserve market operations and optimization of the Pornainen Sand Battery are managed by the software program unit division of Elisa Industriq.

“The Pornainen plant may be adjusted rapidly and exactly, and it additionally has a remarkably lengthy power buffer, making it nicely suited to reserve market optimization. Our AI answer robotically identifies the very best instances to cost and discharge the Sand Battery and allocates flexibility capability to the reserve merchandise that want it most. Steady optimization makes it a genuinely worthwhile funding,” defined Jukka-Pekka Salmenkaita, vice chairman of AI and particular initiatives at Elisa Industriq.

Polar Evening has a transparent imaginative and prescient for the longer term. Building of an electrical energy manufacturing pilot will start within the coming weeks in Valkeakoski, Finland, and the corporate is in lively negotiations for a number of large-scale thermal storage initiatives in district heating, scorching air, and course of steam manufacturing. “Industrial functions are significantly promising, particularly the place warmth above 100°C is required, one thing electrical boilers and warmth pumps can not present,” stated Polar Evening COO Liisa Naskali.

This know-how is rarely going to exchange grid-scale battery storage, however could possibly be helpful in lots of conditions the place battery storage is just not. A touch upon the YouTube video under complained, “Not a phrase about return on funding within the presentation. Which means it’ll by no means repay. They only wasted taxpayers’ cash to stroke their very own egos.” MAGAlomaniacs are all over the place lately.