China launches world’s first grid-forming sodium-ion battery storage plant

China Southern Power Grid (CSG) announced on May 26 the commissioning of the Baochi Energy Storage Station in Wenshan, Yunnan province — a national pilot project and the first large-scale hybrid lithium-sodium battery energy storage facility in China. The plant is also the world’s first to deploy a grid-forming sodium-ion battery system.

With a total investment of over CNY 460 million ($63.8 million)and occupying 34,000 square metres, the Baochi plant is designed for an installed capacity of 200MW/400MWh. Based on a dual daily charge-discharge cycle, it can regulate up to 580 GWh annually — enough to power 270,000 households, with 98 per cent of its energy sourced from renewables. The facility supports more than 30 local wind and solar power stations, alleviating the impact of intermittent supply and facilitating the integration of high shares of renewables into the grid.

The station marks a technical breakthrough by integrating lithium-ion and sodium-ion batteries within the same site. Lithium batteries, known for their maturity and fast response, handle high-frequency grid regulations. Sodium-ion batteries, developed with China’s proprietary technology, offer higher thermal adaptability and greater raw material security. Their maximum output and response speed are reportedly three and six times greater, respectively, than traditional sodium-ion batteries.

Chen Man, a member of the National Energy Storage Standardization Technical Committee, noted that sodium can be widely sourced from salt lakes and seawater, easing dependence on lithium. “In China’s Qarhan Salt Lake alone, sodium reserves are 500 times that of global lithium reserves,” he said, underlining the resource’s scalability potential.

CSG estimates that the hybrid lithium-sodium model reduces system costs by around 30% compared with sodium-only storage, offering a more balanced trade-off between efficiency and economics.

The plant also pioneers the use of a grid-forming energy storage system capable of autonomously adjusting voltage and frequency during grid fluctuations or outages. This self-sustaining system supports various operation modes, including fast and slow charge-discharge cycles, and can act as a “smart stabilizer” for the grid — addressing a long-standing limitation of conventional storage systems that rely on external voltage signals.

Yunnan province, where the plant is located, has one of China’s highest renewable energy penetration rates. As of now, over 70% of its 60 GW total installation capacity comes from renewable sources. The Baochi facility is expected to reduce annual curtailment of wind and solar energy by 120 GWh, improving utilization rates and supporting the stable delivery of power from large-scale desert renewable projects.

Construction of the Baochi Storage Station began in October 2024 and was completed within seven months — a record pace. It will operate under a hybrid “independent + shared” model, ensuring grid regulation capacity while exploring market-based electricity trading mechanisms. Annual revenue is projected to exceed CNY 80 million.

Industry experts view the Baochi project as a milestone in commercializing sodium-ion battery technology and a valuable testbed for grid-forming storage and multi-energy integration. As standardization frameworks develop, lithium-sodium hybrid systems could see broader deployment across China’s renewable-rich regions such as Tibet, Xinjiang, and Gansu. Grid-forming storage is projected to account for up to 40% of China’s new energy storage market by 2030.