From giant earth towers to compressed-air plants, entrepreneurs are piloting systems to make renewable energy more reliable
by David Hodari and Ed Ballard February 14, 2020
In the Alpine town of Arbedo-Castione, Switzerland, an electric-blue, 400-foot-high crane with six heads lifts a block of compacted soil into the air and carefully adds it to the top of a stack.
Later, the crane will reverse that process, generating power as gravity lowers the block back toward the ground.
Energy Vault, the company that built the contraption, believes it could help the renewable-energy industry confront its most intractable problem: storing up energy against the surges and lulls that characterize renewables like wind and solar.
These options are gaining ground as alternatives to fossil fuels, but they can’t yet be relied on to generate power around the clock. Without cheap ways of getting power when it is cloudy or calm, there is a limit to how much the grid can rely on renewables.
“What you’d like to do is power the grid 100% with zero-carbon energy, and there aren’t very many ways to generate it,” says Eric Toone, an emeritus professor of chemistry at Duke University and executive managing director at Breakthrough Energy Ventures, a clean-tech venture fund that has invested in energy-storage startups.
To decarbonize the world’s power with solar and wind, storage capacity also has to grow, he says.
Researchers and entrepreneurs are attacking the challenge of storage from all angles.