China connects the world’s largest LFP battery energy storage system: 4 GWh and grid-forming technology in Inner Mongolia

A gigantic energy storage facility with a power output of 1 GW and a capacity of 4 GWh has begun operating in Inner Mongolia. The DongSu project stands out not only for its record-breaking scale but, above all, as a major milestone in the deployment of grid-forming technology, which can stabilize the grid without relying on conventional power plants.

On August 3, 2026, the DongSu Substation New Energy Storage Special Action project was successfully connected to China’s power grid on its first attempt. Located near the town of Mandulatu in Sonid Left Banner, the facility cost its investor, Wanbang Digital Energy, approximately 3 billion yuan (around USD 445 million) and covers an area of 28 hectares. Local authorities emphasize that it is currently the world’s largest grid-forming LFP battery energy storage system. With a four-hour discharge cycle, the system is expected to deliver approximately 1 TWh of electricity to the grid annually.

Why is grid-forming technology so important in this case?

Most conventional solar PV and energy storage inverters operate in grid-following mode, meaning they require an existing voltage and frequency reference generated by traditional coal- or gas-fired power plants.

The newly commissioned facility uses advanced grid-forming technology:

• Independent stabilization — the inverters establish and maintain local voltage and frequency parameters on their own.
• Strong support for renewables — this enables the safe integration of vast amounts of wind and solar power in the region without increasing the risk of grid failure.
• Black-start capability — the system can independently restore voltage and bring part of the grid back online following a complete blackout.

Inner Mongolia pioneers a new era of renewable energy

Inner Mongolia is one of China’s most important regions for wind and solar power generation. It is also home to the Ulanqab Energy Storage project, which has been included in a list of the world’s largest energy storage facilities.

However, the rapid development of renewable energy in the region is placing enormous pressure on transmission lines. Rather than serving solely to shift energy between periods of low and peak demand, the DongSu project combines four-hour energy storage with immediate support for grid dynamics.

The investment is aligned with China’s latest renewable energy development plan for 2026–2030, published in July 2026. The plan places particular emphasis on deploying grid-forming solutions, improving power-generation forecasting accuracy, and building renewable power plants designed to support the wider electricity system.