Innovative ‘Sand Battery’ is Heating Small City, Storing Green Energy for Months at a Time

A town in Finland is using sand to store heat from renewable energies to provide home heating during winter.

Water heating can only store 100°C of heat, obviously, while sand can reach 500°C, or nearly 1000° Fahrenheit.

Tens of thousands of cubic meters of sand are heated from the generation of electricity with solar panels or wind turbines. Packed tightly in insulated silos, the sand can retain this heat for months without losing it. For Finns living through a 5-month long winter, it’s a vital load off the power grid.

The company behind this innovation, which can also use the heat to generate electricity as well as home heating, is called Polar Night Energy, and the first commercial sand-based heat storage facility has already been bought and made operational by Vatajankoski, an energy utility based in Western Finland.

Now in July, the facility is primed for its first commercial winter in Vatajankoski’s district heating network in Kankaanpää, Finland. The storage has 100 kilowatts heating power and 8 megawatt hours capacity.

For Euro governments, now in the midst of a full blown energy crisis, the sand tech has several attractive elements, such as an investment cost of less than 10 euro per kilowatt hour of capacity, little to no emissions or hazardous materials, and minimal, automated running costs.

The BBC reports that Finnish energy authorities are looking to scale the solution from 8MWh to 8GWh

“This innovation is a part of the smart and green energy transition. Heat storages can significantly help to increase intermittent renewables in the electrical grid,” said Markku Ylönen, co-founder of Polar Night Energy. “At the same time we can prime the waste heat to usable level to heat a city. This is a logical step towards combustion-free heat production.”

And not a moment too soon, as Finland’s Government’s recent decision to join NATO has seen them lose all access to Russian natural gas, the standard home heating energy source.