World’s Largest Sand Battery is Now Storing Wind And Solar Energy
- Editor OGN Daily
- Jul 7
- 2 min read
Capable of storing huge amounts 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 percent.
The team behind the battery - which is 13 metres high and 15 metres wide - have clearly demonstrated that sand is an affordable way to store the plentiful electricity generated when the sun is shining, or the wind blowing at a high rate. Finding a way to store these variable renewables is the crux of unleashing their full potential. Lithium batteries work well for specific applications, but aside from their environmental issues and expense, they cannot take in a huge amount of energy. Grains of sand, it turns out, are surprisingly roomy when it comes to energy storage.
So how do sand batteries work? A tall tower is filled with low-grade sand and charged up with the heat from excess solar and wind electricity. This works by a process called resistive heating, whereby heat is generated through the friction created when an electrical current passes through any material that is not a superconductor. The hot air is then circulated in the container through a heat exchanger.
The sand can store heat at around 500C for several days to even months, providing a valuable store of cheaper energy during the winter. When needed, the battery discharges the hot air - warming water in the district heating network.
The battery’s thermal energy storage capacity equates to almost one month’s heat demand in summer and a one-week demand in winter says Polar Night Energy, the company that built the innovative battery; and it has big ambitions to take its technology worldwide, and is currently in "active discussions" with both Finnish and international partners.
