The Huai’an Salt Cavern project, a major compressed air energy storage facility in China’s Jiangsu Province, has reached full commissioning, marking the completion of what is currently the world’s largest CAES station. The Huai’an Salt Cavern Compressed Air Energy Storage (CAES) demonstration project represents a significant milestone for grid-scale energy storage in China. Shanghai Electric supplied several key components used in the installation, including air turbine units, generators, electric motors and molten salt storage tanks. The Huai’an Salt Cavern project entered its final stage of commissioning after Unit 2 successfully achieved grid connection and reached full-load power generation on its first attempt, providing an operational reference for the development of China’s new-type power system.
The facility comprises two 300 MW non-supplementary combustion CAES units, resulting in a combined installed capacity of 600 MW and energy storage capability of 2,400 MWh, while maintaining conversion efficiency of around 71%. The operational concept used in the Huai’an Salt Cavern project involves compressing air and storing it in underground caverns during periods of low electricity demand. When demand rises, the stored air is released to drive turbines and generate electricity. This cycle supports grid reliability by providing peak shaving and frequency regulation services. The storage infrastructure relies on approximately 980,000 cubic meters of salt caverns located between 1,150 and 1,500 meters underground in Huai’an. To achieve this, the facility applies “molten salt + pressurized thermal water” non-supplementary combustion high-temperature adiabatic compression technology, which allows compression heat to be captured, stored and reused throughout the process without fossil fuel combustion, helping deliver low-carbon performance.
Development of the Huai’an Salt Cavern project progressed in stages, with the first 300 MW unit reaching full-load operation in December 2025 and the second unit entering service recently. The entire installation represents an investment of $520 million. Once fully operational, the station is expected to produce 792 million kWh of electricity annually, an output estimated to supply roughly 600,000 households. In addition to expanding power generation capacity, the facility is projected to reduce energy consumption by saving about 250,000 tons of standard coal each year while lowering CO₂ emissions by approximately 600,000 tons, supporting regional decarbonization efforts.
Equipment for both the power generation and thermal storage segments of the project was delivered by Shanghai Electric Power Generation Group. The company’s role in the Huai’an Salt Cavern project highlights its integrated engineering capabilities across turbine machinery, power equipment and thermal storage systems. This comprehensive scope is intended to provide a replicable equipment framework for long-duration energy storage developments globally. As countries intensify efforts toward carbon neutrality, technologies such as CAES are increasingly viewed as important tools for strengthening grid resilience and enabling higher levels of renewable energy integration. Leveraging experience gained through this project, Shanghai Electric continues advancing high-end equipment manufacturing and integrated energy solutions aimed at supporting global power system modernization.
