World's Largest Sand Battery, world record in Pornainen, Finland
Pornainen, Finland--A giant sand battery, located in Pornainen, Finland, was built by Polar Night Energy; it can store up to 100 megawatt-hours of thermal energy, using 2,000 tons of crushed soapstone to provide heat for the local district heating network and sets the world record for the World's Largest Sand Battery, according to the WORLD RECORD ACADEMY.
"The world's largest sand battery is located in Pornainen, Finland, and was built by Polar Night Energy and commissioned in June 2025. It can store up to 100 megawatt-hours of thermal energy, using 2,000 tonnes of crushed soapstone to provide heat for the local district heating network.
"This system is designed to capture surplus energy from renewable sources and release it as heat when needed, with a thermal power output of 1 megawatt." (AI Overview)
- Location: Pornainen, Finland
- Storage Capacity: 100 megawatt-hours (MWh) of thermal energy
- Material: 2,000 tonnes of crushed soapstone
- Thermal Output: 1 megawatt (MW)
- Function: Stores excess renewable energy as heat, which is then used to heat homes and businesses in the local district heating network
- Significance: This battery is ten times larger than the first commercial sand battery and is expected to reduce the town's heating emissions by 70% by replacing fossil fuels and woodchips. It demonstrates a cost-effective, large-scale energy storage solution for decarbonizing heating."
"Loviisan Lämpö has commissioned the world’s largest Sand Battery. Developed by Polar Night Energy, the industrial-scale Sand Battery now serves as the main production facility for the district heating network in Pornainen, Finland.
"Polar Night Energy has built an industrial-scale Sand Battery in Pornainen for Loviisan Lämpö’s district heating network. The new Sand Battery delivers 1 MW of thermal power and offers a storage capacity of 100 MWh, making it ten times larger than the Sand Battery launched in Kankaanpää in 2022," the official website says.
"Developed by Polar Night Energy, the Sand Battery is a high-temperature thermal energy storage system that stores clean and affordable electricity as heat in sand or similar solid materials. It can be used to produce heat for both district heating networks and a wide range of industrial processes."
"Finland has inaugurated an industrial-scale sand battery this week in the southern town of Pornainen, where it'll take over heating duties from an old woodchip power plant for the municipality. It's set to reduce carbon emissions from the local heating network by as much as 70%, and is the largest one of its kind in the world," the New Atlas reports.
"Developed by Finnish Firm Polar Night Energy – which also built the world's first commercial sand battery a few years ago – this battery is about 42 ft (13 m) tall and 50 ft (15 m) wide. It serves as a storage medium for up to 100 MWh, with a round trip efficiency of 90%. That makes it about 10 times larger than the first-ever sand battery, and capable of storing enough heat for the whole town to use for a week.
"This Thermal Energy Storage (TES) reservoir is a critical tool for places like Finland, which intermittently generate vast quantities of wind and solar electricity, but also face variations in energy demand and supply. The sand battery charges up when electricity is cheaply available and can hold a charge for months at a time, helping balance the energy grid during periods of high demand."
"The world’s largest sand battery has started working in the southern Finnish town of Pornainen. Capable of storing 100 MWh of thermal energy from solar and wind sources, it will enable residents to eliminate oil from their district heating network, thereby cutting emissions by nearly 70 per cent," the Euro News reports.
"The industrial-scale solution from Finnish company Polar Night Energy is now the primary production plant for the network. The consumption of wood chips is set to drop by around 60 per cent as a result, while the existing biomass boiler will continue to serve as a backup and support the sand battery during peak demand periods.
"Finding a way to store these variable renewables is the crux of unleashing their full potential. Lithium batteries work well for specific applications, explains Markku, but aside from their environmental issues and expense, they cannot take in a huge amount of energy."
"The Sand Battery is a large-scale, high-temperature thermal energy storage system that uses sand or similar materials as its storage medium. It enables our clients to meet their climate goals while significantly reducing energy costs," the Polar Night Energy says.
"Designed to decarbonize entire energy systems, perfect for large-scale industrial processes, energy companies, district heating networks, or space heating needs.
- Large high-temperature thermal energy storage system
- 10 MW heating power with a capacity of up to 1000 MWh
- Scalable to meet even greater heating demands
- Approximate round trip efficiency 90%
- Approximate dimensions: 30 x 12 m
- Dramatically reduces carbon emissions and energy costs
- Modular and flexible for easy integration with renewable energy sources
"Thermal energy storage (TES) is the storage of thermal energy for later reuse. Employing widely different technologies, it allows surplus thermal energy to be stored for hours, days, or months.
"Scale both of storage and use vary from small to large – from individual processes to district, town, or region. Usage examples are the balancing of energy demand between daytime and nighttime, storing summer heat for winter heating, or winter cold for summer cooling (Seasonal thermal energy storage).
"Storage media include water or ice-slush tanks, masses of native earth or bedrock accessed with heat exchangers by means of boreholes, deep aquifers contained between impermeable strata; shallow, lined pits filled with gravel and water and insulated at the top, as well as eutectic solutions and phase-change materials." (Wikipedia)
"A small municipality in southern Finland recently installed the world's largest "sand battery" to supply the town's heating. The new sand battery, designed by Polar Night Energy, is effectively a giant sandpit encased in a roughly 43 foot tall by 49 foot wide (13 by 15 meter) steel container," the
Live Science reports.
"The sand is heated using closed-loop heat transfer pipes and this heat is trapped by two layers of steel sandwiching an insulation layer. The energy is then extracted by blowing cool air through the pipes, capturing the heat to generate hot water, steam or hot air."
"The world’s largest sand battery has just been turned on. The battery, which is simple in design, can store heat during periods of excess renewable energy. It then stores the heat and can deliver it on demand, enabling municipalities to eliminate fossil fuels from the heating network," ZME Science says.
"A sand battery uses sand or crushed rock to store heat. This stored head can later be used for various purposes. It might not be as imposing as a large lithium-ion battery, but this 2,000 metric ton battery helped a Finnish town eliminate the costly and polluting oil it was previously using.
"The economic case is compelling. It’s hard to think of a cheaper material than sand. In fact, in this case, the sand was basically trash discarded by a Finnish fireplace maker. The sand is stored in a silo-type structure and then an electrical current is passed through it. Sand isn’t a conductor so it resists the current, creating heat in the process."
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