Warm walls help generate energy.
Now, the startup of a Finnish research team is using sand to store solar- and wind electricity.
The renewable energy powers a device that circulates hot air in a silo with some 100 tons of sand which heats up to 600-1000℃.
This way energy can be stored for months without using lithium and cater to locals in the cold Finnish winter. The heat provides for furnaces and hot water.
When deployed in the industrial sector, this reduces fossil fuel usage. The first low-emission storage device with 100 kW heating power is already in use.