China has signed deals to deploy five more gravity-based energy storage systems, in what developer Energy Vault said now amounts to $1bn-worth of project scope in the innovative technology.

US-based Energy Vault said power group China Tianying will deploy another 1.2GWh across five provinces, adding to the 2.1GWh already announced.

Energy Vault – which collects a 5% revenue royalty for licensing the technology – claimed the latest agreements show gravity-based systems are carving out a role alongside dominant pumped-hydro as a long-duration energy storage solution in the world’s biggest renewable energy market.

The total planned by China Tianying now amounts to $1bn in project scope, it reckons.

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.

The company is currently commissioning its first large-scale system, a “world first” 100MWh system adjacent to a wind farm in Rudong near Shanghai, in conjunction with Atlas Renewable Energy, a Latin American investment vehicle, and China Tianying.

Energy Vault expects to benefit from Chinese rules that require renewable energy plants to integrate storage equivalent to 20% of their generation capacity, with at least a 2–4-hour duration.

It is also counting on the local content benefits of souring locally-made materials to make its bricks.

China Tianying chairman Yan Shengjun said the power group is “quickly expanding this groundbreaking technology that will enable intermittent wind and solar power generation to more readily replace other fossil fuel-based generation, and thus help accelerate China’s clean energy transition and achievement of its net carbon neutral goals.”

Energy Vault commercial chief Marco Terruzzin this week claimed to Recharge that fires are set to surge due to the deployment of increasing numbers of Li-ion battery systems.

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