The world’s largest compressed air energy storage station has now become fully operational. The Huai’an Salt Cavern Compressed Air Energy Storage (CAES) is situated in China’s Jiangsu Province.
Recently, the CAES system received air turbine units, generators, electric motors, molten salt storage tanks, and other core equipment from Shanghai Electric.
With two 300 MW non‑supplementary combustion CAES units, the project has a total installed capacity of 600 MW and 2,400 MWh of storage, with approximately 71% conversion efficiency.
Recently, the project’s Unit 2 successfully achieved grid connection and full-load power generation at the first attempt, providing valuable engineering practice in support of China’s new-type power system development.
In the CAES system, air is compressed and stored in salt caverns during low‑demand periods, then released to drive turbines for power generation at peak times, supporting grid stability through peak shaving and frequency regulation.
The single unit power, energy storage capacity and conversion efficiency of this project rank first globally among similar salt cavern CAES power plants, according to the company.
The Project employs “molten salt + pressurized thermal water” non‑supplementary combustion high‑temperature adiabatic compression technology. This enables compressed heat to be stored and reused throughout the process without fossil fuel combustion, delivering significant low‑carbon benefits, according to a press release.
Shanghai Electric revealed that the first 300 MW unit reached full-load operation in December 2025, followed by Unit 2’s recent commissioning. With a total investment of $520 million, the fully operational station is expected to generate 792 million kWh of electricity annually, that is enough to power around 600,000 households.
It will save approximately 250,000 tons of standard coal and cut CO₂ emissions by 600,000 tons each year, delivering a measurable impact on the region’s energy transition. Shanghai Electric Power Generation Group supplied core equipment for the Project covering both power generation and thermal storage systems, as per the release.
It’s also being claimed that the construction of salt cavern CAES power plants can effectively address the volatility, intermittency and randomness of renewable energy generation.
The principle of CAES in salt caverns is similar to that of conventional pumped storage power plants.