• Tech Tech

This innovative ‘sand battery’ may help solve one of green energy’s greatest dilemmas — here’s how

Sand is considered very effective at retaining heat.

Providing energy year-round has so far presented one of green power’s most insurmountable challenges — but now the world’s first fully functional sand battery, which can store green power for months, could present a valuable solution.

According to BBC News, engineers working for Finnish company Polar Night Energy have put sand to work. They installed the first sand battery in July 2022 and have seen promising results so far. The sand is stored in a simple silo, a humble innovation that may help provide a path forward for cleaner, cheaper energy as a viable, sustainable part of everyday life. 

While green energy sources are often readily available at certain times of the year, a long-running concern has been finding avenues to store that energy for colder months, when more families and businesses need to turn up the heat.   

How would sand batteries work?

First, existing solar panels and wind turbines would generate electricity using natural and available sources. 

Some of that electricity would be put to use directly and immediately through an electrical grid to meet current demands, but the remaining, unused energy could be stored as heat in a sand battery, which can be warmed up to 500 degrees Celsius (around 932 degrees Fahrenheit) using the same heat-exchange process that fuels electric fires. 

Sand is considered very effective at retaining heat, and under the right circumstances, it could hold that 500 degrees Celsius worth of warmth for months at a time. 

Finally, the heat that had been stored could be used to provide hot water heating in order to warm up buildings year-round. 

Tucked away in a corner of a small power plant in western Finland, the geographic location of this sand battery pilot may prove to be an ideal scenario for testing the results. With rising prices of dirty energy sources like fossil fuel and cold winter months just ahead, interest in renewable energy sources is rising. 

Intermittency — energy sources that ebb and flow, such as solar energy’s dependence on sunlight — has remained a concern and has prompted energy providers to continue to rely on energy from dirty and expensive fossil fuels to balance out availability. 

Residents of the small town of Kankaanpää, where the pilot is taking place, will have a chance this winter to test out the results of the sand battery, engineered by the founders of Polar Night Energy. The new company installed the device in the Vatajankoski power plant, which operates the town’s heating system. 

The next question will be whether it can be scaled for broader use and even more impactful applications, such as providing electricity as well as a heat source for hot water.

Getting energy from renewable sources is ideal in many ways, as clean energy is often cheaper and has less of a negative impact on our overheating planet, but those sources may only provide truly sustainable solutions if the energy becomes reliable and available when people need it. 

Sand batteries may provide one answer to help combat climate change and provide a stable, clean source of year-round heat. 

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