A battery that uses sand to store heat for months and could help with the green energy transition has been unveiled in Finland in a world first.
The sand battery will be used to provide heating to homes in the city of Kankaanpää in Western Finland, as well as its local swimming pool.
Researchers say it could help solve the problem of how to store renewable energy such as wind and solar as it can be used when the sun is not shining or the wind is not blowing.
The sand, which can reach temperatures of 600C, provides an alternative to lithium-ion batteries, which rely on expensive and relatively scarce metals and can only store a limited amount of energy.
The initial version installed in Kankaanpää uses 100 tons of sand in a seven-metre-high steel container to store energy on a site at the local power plant which will provide district heating to around 100 homes in the area throughout the year.
Eventually, the researchers plan to scale up to create batteries around 100 times that size, which would be able to take advantage of sunny or windy periods to store up energy.
“This innovation is a part of the smart and green energy transition,” said Markku Ylönen, the co-founder of Polar Night Energy, which came up with the sand battery.
Other countries are working on similar sand battery projects, including the American National Renewable Energy Laboratory, but Polar Night Energy says it is the first fully operational commercial scale project.
Sand is the world’s second most used resource, and facing growing shortages, but Mr Ylonen said the battery storage would use “low value” and “sand like” substances, to allay concerns about running out of raw materials.
The final major challenge for the project will be to use the energy in the sand to discharge electricity, rather than simply heat.
Although it can be done, with current technology the process is inefficient and therefore too expensive to be done at scale.
One of the best uses of the sand battery may be to provide energy for industrial processes that require a lot of heat, said Mr Ylonen.