China switches on the world's largest grid-forming battery — 4 GWh in Inner Mongolia

China connected the world's largest single-site grid-forming lithium iron phosphate (LFP) battery storage plant to the grid on August 3. The DongSu facility in Inner Mongolia, built by Wanbang Digital Energy, has a power rating of 1 GW and a storage capacity of 4 GWh. That puts it ahead of North America's largest battery project, the Moss Landing installation in California at 3.9 GWh — and it signals how quickly China is pulling ahead on grid-scale storage.

The tech

DongSu isn't just big — it's built differently from most battery plants. Standard grid-tied storage systems are "grid-following": they read existing voltage and frequency on the network and match them. DongSu uses grid-forming inverters, which can set voltage and frequency independently. That matters because solar and wind farms don't spin like a gas turbine; they contribute no natural inertia to the grid. Grid-forming storage fills that gap, providing what engineers call synthetic inertia — an instant electronic buffer that keeps the lights on when generation suddenly dips. It's the kind of capability that becomes essential once renewables cross roughly 50% of a grid's supply mix.

The project covers 28 hectares — roughly 50 American football fields — and cost CNY 3 billion (around $445 million). Per ESS News, local authorities expect it to discharge about 1 TWh of electricity per year.

The gap

Inner Mongolia has been aggressively expanding wind and solar capacity, creating exactly the grid-balancing headaches that DongSu is designed to solve. Surplus renewable power that would otherwise be curtailed — wasted — can now be stored and dispatched during peak demand.

The broader context is competitive. The EU is moving to require grid-forming capability for any new storage project above 1 MW from 2027 under its updated network code (NC RfG 2.0). China is already deploying it at gigawatt scale. US projects face a different bottleneck: lengthy FERC interconnection queues slow the pace of large-scale builds regardless of the technology involved.

China has announced plans to roll out further DongSu-scale projects between 2026 and 2030, pairing them with smarter grid-management software and improved generation forecasting. Whether Western grids can close that deployment gap before the regulatory deadlines arrive is a question the energy industry will be watching closely.