According to Spectrum, several companies are poised to make a splash storing energy with gravity. That sounds fancy and high tech at first, but is it, really? Sure, we usually think of energy storage as some sort of battery, but there are many energy storage systems that use water falling, for example, which is almost what this new technology is all about. Almost, since instead of water these new systems move around multi-ton blocks.
The idea itself is nothing new. You probably learned in high school that you have kinetic energy when a rock rolls down a hill, but a rock sitting on a mountain immobile has potential energy. These systems use the same idea. Moving the “rock” up stores energy and letting it fall releases the same energy. The big difference between the systems is what “up” means.
For Swiss company Energy Vault, the 35 metric ton bricks rise into the air manipulated by towers that look like alien construction cranes. To store energy, the crane builds a tower of bricks around itself. When the bricks return to the ground, they form a lower ring around the tower.