From around the world: the world's first large-scale integration of lithium and sodium ion technologies

With a total investment of over CNY 460 million (USD 63.8 million) and covering an area of 34,000 square meters, the Baochi plant is designed for an installed capacity of 200 MW/400 MWh. Based on a double daily charging and discharging cycle, it can regulate up to 580 GWh per year, enough to power 270,000 households, with 98% of the energy coming from renewable sources. The facility supports more than 30 local wind and solar power plants, mitigating the effects of intermittent energy supply and facilitating the integration of a high share of renewables into the grid.

The station represents a technical breakthrough by integrating lithium-ion and sodium batteries in the same location. Lithium batteries, known for their sophistication and fast response, can handle high-frequency grid regulation. Sodium batteries, developed using Chinese proprietary technology, offer higher thermal adaptability and greater raw material safety.

Their maximum power and response speed are reportedly three and six times higher than those of traditional sodium batteries, respectively. Chen Man, a member of the National Technical Committee for Energy Storage Standardization, noted that sodium can be extracted from salt lakes and seawater, reducing dependence on lithium.

"In China's Qarhan salt lake alone, sodium reserves are 500 times greater than global lithium reserves," he said, highlighting the potential of this resource in terms of scalability.

CSG estimates that the lithium-sodium hybrid model reduces system costs by approximately 30% compared to sodium-only storage and offers a more balanced compromise between efficiency and economy.

The plant is also a pioneer in the use of 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 and 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.

The province of Yunnan, where the power 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 annual wind and solar energy curtailment by 120 GWh, improving utilization rates and supporting stable energy supply from large renewable energy projects in the desert.

Construction of the Baochi storage facility began in October 2024 and was completed in a record seven months. It will operate on a hybrid "independent + shared" model, providing grid regulation capacity while allowing for the exploration of market mechanisms for electricity trading. Annual revenue is expected to exceed CNY 80 million.

Industry experts consider the Baochi project a milestone in the commercialization of sodium-ion battery technology and a valuable test platform for energy storage for grid formation and multi-energy integration. With the development of standardization frameworks, lithium-sodium hybrid systems could expand in Chinese regions rich in renewable resources, such as Tibet, Xinjiang, and Gansu. By 2030, energy storage for grid formation is expected to account for up to 40% of China's market for new energy storage methods.