From ESS News
Finnish cleantech startup TheStorage says that its thermal storage technology could reduce industrial energy costs by up to 70% and cut carbon emissions by as much as 90%. The system converts renewable electricity into heat, stores it in sand, and delivers it on-demand for industrial heating.
The concept emerged in Finland in 2023, with engineering work beginning in 2024. In January 2026, TheStorage installed its first industrial-scale pilot at a brewery, putting the technology to the test in a real-world setting. There, it produces fossil-free steam for the brewery’s production lines.
“Producing steam without fossil fuels is a major step toward carbon-neutral production,” says Vesa Peltola, Production Director of the brewery.
TheStorage’s technology captures electricity when it is abundant and inexpensive, converts it into high-temperature heat, and stores it in sand. This stored heat can later be used in industrial processes independently of real-time electricity availability.
“Companies have wanted to decarbonize for years, but viable solutions simply weren’t available. Finally, renewable energy generation can meet industrial heat demand in a way that’s both ecologically sound and economically practical,” says Timo Siukkola, CEO of TheStorage.
The principle behind TheStorage’s system is straightforward. Heat is stored in ordinary sand using two insulated silos, an electric heater, and a heat exchanger.
Cool sand moves from a cold silo to an electric heater, where it is heated to temperatures up to 800°C. The heated sand is then stored in a hot silo, retaining energy efficiently. By circulating the sand through an external heat exchanger, the system delivers steam with up to ten times higher heat transfer efficiency compared to conventional static storage systems.
The stored heat can be released on-demand as steam or thermal oil, providing stable energy that can quickly adapt to changing industrial demand. The solution is scalable from 20 to 500 MWh with charging power ranging from 1 to 20 MW, depending on the industrial application and individual project needs. Both charging and discharging operations are fully flexible.
Last year, Finland’s PolarNight inagurated the world’s largest sand battery – a 1 MW/100 MWh thermal storage system. In November, the company has committed to building a project twice its size. This sand battery will provide 2 MW of thermal output and 250 MWh of storage capacity, positioning it as the world’s largest sand-based thermal energy storage system upon completion.
In 2022, Polar Night Energy switched on the world’s first commercial sand-based, high-temperature heat storage system in the Finnish city of Kankaanpää, with 100 kW of power output and 8 MWh of storage capacity.
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