Green energy solutions have evolved from just generating it to storing it.
As a result of climate change and the rapid increase in the price of fossil fuels, there’s a rise in new renewable energy production globally.
However, the challenge with solar or wind energy is intermittency; how do we keep the lights on when the sun doesn’t shine, or the wind doesn’t blow?
Finnish engineers have found a clean, low-cost, environment-friendly way to store green energy. Polar Night Energy has installed the world’s first fully working “sand battery” capable of storing green power for months and solving the issue of year-round supply.
What Is Sand Battery?
A sand battery converts electricity to heat and can be stored for later use. Sand is one of the cheapest mediums for storing heat; it’s very efficient and loses little over time.
How Exactly Does It Work?
A 4×7 meter steel container is filled with thousands of tonnes of sand. The sand is then heated with solar or wind energy and stored for use by a local energy provider to heat the community.
Unlike lithium-ion batteries, a sand battery uses resistive heating due to “friction,” created by microscopic phenomena to increase the ambient temperature, which is then transferred to sand with a heat exchanger.
Also, sand has a really high melting temperature and can store heat energy for months, making sand batteries a viable long-term storage solution.
Polar Night Energy (PNE) created the first commercial sand battery in Kankaanpää, western Finland, which currently powers the central heating system in the neighborhood.
According to PNE, the hot air in the battery can be used to warm water and pumped to offices, homes, and the local swimming pool when required.
With the first working commercial sand battery in place, It may only be a matter of time before this low-cost, efficient technology becomes commonplace in the world’s electricity grids.
Image by Polar Night Energy