A ‘first-of-its-kind’ 100MWh gravity energy storage system is preparing to enter operation near Shanghai, with plans for several other facilities using the technology reportedly in the pipeline.

Switzerland-based Energy Vault announced that it has finished building critical power components of the facility and that commissioning is underway. It is expected to come online later this year.

Located outside of Shanghai, the 25MW/100MWh gravity storage system is built next to a wind farm and a national grid interconnection site.

Energy Vault claims its technology, based around ‘storage towers’ of custom-designed bricks, replicates the gravity-based approach of large-scale pumped-hydro storage, but at lower cost and without the need for water or particular topographies. Instead of water, the huge bricks are hauled upwards by crane to store energy and released for discharge, controlled by custom-designed software.

Energy Vault says it has had round trip efficiency results of over 75% at a smaller facility in Switzerland. Now it says it has an enhanced new system that it expects to reach over 80% efficiency.

This puts the new gravity system as “a leader in energy storage efficiency versus all other forms of mechanical, thermodynamic processes, compressed air or flow battery systems,” claims Energy Vault.

Energy Vault has worked on its latest project with partners Atlas Renewable Energy, a Latin American investment vehicle, and local partner China Tianying.

Energy Vault CEO Robert Piconi said, while the project had reached a “significant milestone,” his company’s work in China is “just beginning given recent local announcements of multi-GW hours of gravity energy storage buildouts.”

He said this includes a plan announced last year to build a 2GWh gravity energy storage project that will serve one of China’s zero carbon industrial parks.

More recently, the company said that a China Tianying subsidiary had signed a deal for its storage technology to build another 100MWh facility in the eastern province of Hebei, which surrounds Beijing. The facility will service data centres in the region.

Others active in the gravity storage space include Gravitricity, which uses giant weights hung in deep shafts to store energy.

Gravity energy storage is one of several pioneering technologies being developed to help capture excess energy produced by wind and solar farms. A Danish island was last year announced as the host of what is being claimed as “game changing” molten salts-based storage technology. Developers have also been working on liquid-air cryogenic energy storage.