When I first read that Finland has inaugurated world’s largest sand battery, the fist question I had was “What is a sand battery?”. Is it a new battery that uses Sand somehow instead of Lithium-Ion or similar tech to product power? Then I read up more about it and the answer is even cooler. As per Wikipedia, this is a Thermal battery, using sand as a heat storage medium to power generators using stored power. The following diagram has a good explanation on how the tech works:
1. Electricity is generated by Wind Turbines or Solar (or other power generation sources)
2. 30% of the energy is used to power the local infrastructure
3. The remaining 70% is stored in the Sand battery by heating the sand up to 600-1000 Degree C.
4. The stored energy is used to generate power or provide heating during winter months or at night.
Pic Source: Drishtiias.com: Solar Batteries
The advantage of using Sand for storing heat is that it is cheap and a very effective medium for retaining heat over long periods of time. Once the energy is stored as heat it can then be used to heat homes, or to provide hot steam and high temperature process heat to industries that are often fossil-fuel dependent.
Polar Night Energy said the battery has met expectations in its first months and exceeded guaranteed efficiency targets. It has replaced the area’s old woodchip plant all summer.
A sand battery stores clean electricity as heat in sand or other solid materials. The Pornainen unit stands nearly 13 meters tall and 15 meters wide, delivers 1 MW of thermal power, offers 100 MWh of storage, and contains roughly 2,000 tons of crushed soapstone.
Polar Night Energy said the battery can participate in electricity reserve markets, charging according to electricity prices and Fingrid’s reserve market signals. Its storage capacity allows consumption to be optimized over days or weeks and helps balance the grid.
Finnish Minister of the Environment Sari Multala said thermal storage improves energy system flexibility and reduces industrial emissions.
I can see this tech (once it matures) being used in areas that have a large temperature fluctuation on a daily or yearly basis like deserts. During the day we can charge the reservoir up and then use it at night to heat homes. In a way it is a larger application of how the traditional homes in desert areas are built using mud.
Source: @janrosenow.bsky.social
– Suramya