Several companies are set to make a splash by storing energy by gravity, according to Spectrum. It sounds sophisticated and high-tech at first, but is it really? Of course, we generally think of energy storage as a kind of battery, but there are a lot of energy storage systems that use waterfalls, for example, which is almost the subject of this new technology. . Almost, since instead of water, these new systems move around blocks of several tons.
The idea itself is nothing new. You probably learned in high school that you have kinetic energy when a boulder rolls down a hill, but a boulder sitting on a stationary mountain has potential energy. These systems use the same idea. Moving the “rock” upwards stores energy and letting it fall releases the same energy. The big difference between the systems is what “up” means.
For the Swiss company Energy Vault, the 35-ton bricks rise into the air manipulated by towers that resemble alien construction cranes. To store energy, the crane builds a tower of bricks around it. When the bricks return to the ground, they form a lower ring around the tower.
Another company, based in Scotland, Gravitricity, uses weights of up to 5,000 metric tonnes and moves them up and down in very deep mine shafts, an approach shared by several other companies in this field. Some systems use the mechanical movement of the falling weight while others use the weight as a piston to pass water through a fairly ordinary generator.
Why not use batteries? According to the post, Energy Vault claims that blocks made of dirt, trash and polymer are environmentally friendly compared to batteries. The blocks don’t wear out much either, so running costs are low as there isn’t much to replace frequently like batteries do.
The scale of weights is hard to imagine. Another company, Gravity Power, claims to be able to deliver 400 megawatts for 16 hours using an 8 million metric ton piston. However, it is not known how long it takes to return this piston to the loaded position after the 16 hours. A Boeing 757-200, for example, weighs around 100 tonnes when loaded with fuel and passengers. So imagine 80,000 giant planes melted down. This makes Energy Vault’s 35 ton weights much more reasonable.
Keep in mind that these systems do not generate electricity. They are storing it, so there will be a loss. However, the principle of these is simple, the only complication is the scale. We wondered if anyone had used some sort of system like this on a small scale on a project that would normally have used rechargeable batteries? It sounds like a weekend project and if you do, be sure to let us know.