A New Type of Battery, Made of Concrete
How one company is thinking ‘outside the blocks’ and storing energy in concrete towers
A couple of hours south of Zürich, Switzerland, in the Canton of Ticino, you’ll find a battery made out of concrete blocks. Energy Vault, the Swiss clean energy firm that built it, is about to go public via a SPAC merger with Novus Capital Corporation II.
The sun doesn’t always shine, nor does the wind always blow. Neither lines up exactly with when we use the most electricity. As a result, renewable energy has an issue: How do you balance out demand with supply (lack or excess thereof)? One answer has been through energy storage. Batteries.
You may have already heard about Tesla’s utility-grade mega-battery packs, or perhaps even pumped hydro — where excess electricity is used to pump water up into a dam’s reservoir to be turned back into electricity later. But there are other types of batteries. For example: blocks of concrete!
I know what you’re thinking: “How can blocks of concrete store energy?” The answer can be found in high school physics. Just like with pumped hydro, the trick is converting electricity into potential energy — a type of energy store with the potential to be turned back into electricity — by driving a generator.
Energy Vault’s battery does this by stacking concrete blocks into an organized potential-energy-rich tower. The battery is charged by using excess electricity to power crane motors which lift concrete blocks. The higher a block is lifted, the more potential energy it has stored. Later, the battery can be discharged by driving the crane motors in reverse, converting the concrete block’s potential energy back into electricity.
Surprisingly, the whole thing is relatively efficient. The round-trip efficiency of the system, from stacking to unstacking, is about 85% — roughly on par with lithium-ion batteries, which offer up to 90%.