China built a 40-story tower that stores wind power by stacking concrete

The Swiss company Energy Vault spent years pitching a novel idea: store surplus electricity by using it to stack heavy blocks, then recover the power by letting them fall. Boing Boing covered the skeptics in 2021. The company kept building, and there's now a 148-meter tower in Rudong, Jiangsu doing exactly that with a nearby wind farm.

Surplus wind power hoists 35-ton blocks cast from recycled concrete and industrial aggregate toward the top. When the grid needs electricity again, the blocks descend and spin the generators. The tower stores 100 megawatt-hours and can deliver 25 megawatts for about four hours, at a targeted round-trip efficiency above 80 percent, with a 35-year lifespan and no chemical degradation.

China Tianying built and funded it; grid interconnection came in December 2023. Nine more towers are planned across China, totaling over 3.7 gigawatt-hours. Unlike pumped hydro, a gravity tower needs only flat ground.

Previously:

• This video debunks the much-hyped Energy Vault
• Turning bricks into batteries