Is Sand the New Lithium?

The answer to powering Advanced Air Mobility may be shifting in a desert nearby.

If you’ve ever walked barefoot on the beach on a hot day, you know you literally feel the heat. Heat is stored energy, stored energy that could be used to power homes, offices, cars (maybe even flying ones?!).

Perhaps best of all, sand – unlike lithium – is practically everywhere, on every continent save the North and South poles. We’ve got deserts full of the stuff all over Planet Earth.

Researchers at Polar Night Energy in Finland have already devised a method to extract energy from sand. Next up in the lab: Can it be scaled commercially?

Speaking to the BBC, the scientists explained they have successfully raised the temperature of their sand sample to about 500°C (about 932°F).

Perhaps as optimistic as they are realistic, Polar Night Energy believes its process may remove as much as 100Mt CO2e annually – an amount that is barely equivalent to three percent (3%) of the EU’s current emissions.

The stored renewable energy can later be used in different energy demanding processes, replacing fossil-based combustion technologies that are common nowadays for heating and electricity production.

Will Silica Store Energy so eVTOLs Can Soar?

The NREL uses this illustration to help envision how their sand-y storage system will work. (Image copyright and courtesy of NREL.)

The Finns aren’t the only ones with their sights focused on storing heat in silica sand. Speaking to Energy, the National Renewable Energy Laboratory (NREL), a division of the U.S. Department of Energy, is also testing thermal energy storage technologies using silica sand particles.

The researchers hope to obtain long-term electricity storage using low-cost thermal energy storage and high-efficiency power cycles. The NREL team feeds particles through a series of electric resistive heating elements to 1200°C (about 2192°F) and then gravity-feeds them into insulated concrete silos for thermal energy storage.

Their initial system envisions storing 26,000 MWh of thermal energy with the ability to scale up or down as needed due to its modular design.

A Swirling Sandstorm of Interest

In 2014, researchers at the University of California, Riverside’s Bourn’s College of Engineering developed a lithium-ion battery composed of sand that they claim outperformed the industry standard by three-fold (click here). Scaling and rapid degradation were issues then, but may no longer be a problem.

Other enterprises exploring the science of sand-based energy that may some day power eVTOLs (imaging pulling up to a sand pump and saying “Fill ‘er up with Sahara Premium”) include: Tesla, Mercedes-Benz, Alameda, California-based Sila Technologies, and Australia’s Allup Silica.

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