China's compressed air energy station to power 600,000 households
The world’s largest compressed air energy storage station has now become fully operational, according to a report.
Situated in China’s Jiangsu Province, the Huai’an Salt Cavern Compressed Air Energy Storage (CAES) demonstration project has recently been fully commissioned. The project recently 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 600 MW of total installed capacity and 2,400 MWh of storage, with approximately 71% conversion efficiency.
Unit 2 successfully achieved grid connection
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.
Super power bank
The project utilizes the caverns of an abandoned salt mine, about 1,150 to 1,500 meters deep, as its gas storage facility. This approach creates a super “power bank” with a single unit power output of up to 300 MW and a storage capacity of 2,400 MWh. The system’s conversion efficiency is about 70 percent, according to China Energy Digital Technology Group Co., Ltd., one of the project’s major investors.
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.
Enough to power around 600,000 households.
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.
During periods of low electricity demand, electrical energy is used to compress air and store it in underground salt caverns. The compressed air can then be released during periods of peak demand to generate electricity, according to China Energy Digital Technology Group Co., Ltd., one of the project’s major investors.
Previously, the Institute of Rock and Soil Mechanics (IRSM) of the Chinese Academy of Sciences revealed that the deep underground gas storage is the key to CAES projects.
However, China’s most salt mines have a high content of impurities, with sediment occupying significant underground space.