For the same 25 MW / 100 MWh four-hour service, Energy Vault’s Rudong project requires far more capital, land, machinery and construction carbon than a contemporary Chinese BESS.
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Energy Vault’s Rudong gravity-storage project is a particularly useful technology test because it removes many of the excuses that can surround a first-of-kind energy project. It was built in China, with deep domestic supply chains for concrete, steel, motors, power electronics and industrial construction. It had government support, grid coordination and an experienced Chinese construction partner. If stacking and lowering solid masses inside a purpose-built structure could become competitive grid storage, Rudong was about as favorable a place as possible to find out.
What emerged is an extraordinary amount of machine for a fairly ordinary amount of electricity storage. Rudong is rated at 25 MW and 100 MWh, meaning four hours at full output. The structure is roughly 148 metres high, with more than 12,000 nominally 25-ton blocks, 96 lifts and thousands of bored piles beneath it. Energy Vault’s own project page still describes the system as commissioning, despite saying full grid interconnection was expected by the end of 2023.
