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The Baochi storage station in Yunnan integrates lithium and sodium-ion technologies on a large scale, a first for the world, with the goal of stabilizing renewable energy and reducing costs as China accelerates its energy transition. 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 lithium-sodium battery hybrid energy storage facility in China. The plant is also the first in the world to deploy a grid-forming sodium-ion battery system. With a total investment of over 460 million yuan (63.8 million USD) and a surface area of ??34,000 square meters, the Baochi plant is designed for an installed capacity of 200 MW/400 MWh. Based on a daily dual charge-discharge cycle, it can regulate up to 580 GWh annually, enough to supply 270,000 households, with 98% of its energy coming from renewable sources. The facility supports more than 30 local wind and solar power plants, alleviates the impact of intermittent supply, and facilitates the integration of high shares of renewables into the grid. The station marks a technical breakthrough by integrating lithium-ion and sodium-ion batteries in a single location. Lithium batteries, renowned for their maturity and rapid response, manage high-frequency regulation on the grid. Sodium-ion batteries, developed with proprietary Chinese technology, offer greater thermal adaptability and greater security in the supply of raw materials. Their peak power and response speed are reportedly three and six times higher, respectively, than traditional sodium-ion batteries. Chen Man, a member of the National Energy Storage Standardization Technical Committee, noted that sodium can be widely obtained from salt lakes and seawater, reducing dependence on lithium. “In Lake Qarhan in China alone, sodium reserves are 500 times larger than the worlds lithium reserves,” he said, highlighting the resources scalability potential. CSG estimates that the lithium-sodium hybrid model reduces system costs by about 30% compared to sodium-only storage, offering a better balance between efficiency and cost-effectiveness. The plant also innovates by utilizing a grid-forming energy storage system capable of autonomously adjusting voltage and frequency during grid fluctuations or outages. This self-sufficient system supports various operating modes, including fast and slow charge-discharge cycles, and can act as a “smart stabilizer” for the grid, addressing a historical limitation of conventional storage systems that rely on external voltage signals. Yunnan Province, where the plant is located, has one of the highest renewable energy penetration rates in China. Currently, more than 70% of its total installed capacity of 60 GW comes from renewable sources. The Baochi facility is expected to reduce the annual curtailment of wind and solar power by 120 GWh, improve utilization rates, and support the stable delivery of power from large renewable projects in the desert. Construction of the Baochi storage station began in October 2024 and was completed in seven months, a record pace. It will operate under a hybrid independent + shared model, ensuring grid regulation capacity while exploring market-based power trading mechanisms. Annual revenue is projected to exceed 80 million yuan. Industry experts regard the Baochi project as a milestone in the commercialization of 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 be widely deployed in renewable-rich Chinese regions such as Tibet, Xinjiang, and Gansu. Grid-forming storage is projected to account for up to 40% of Chinas new energy storage market by 2030. |
