China Huaneng said the two main units of the phase-two 2×350 MW salt cavern compressed air energy storage (CAES) project in Jintan completed full-set startup on September 12, with equipment operating stably and reliably, marking a key breakthrough in core technology and system integration for large-capacity salt cavern CAES in China.

The project, located in Jintan district of Changzhou, Jiangsu province, is currently the world's largest salt cavern CAES station by single-unit capacity, total capacity and overall efficiency.

It plans two 350 MW non-supplementary-fired CAES units, with 8 hours of storage and 4 hours of generation, an energy conversion efficiency of over 70%, and a single charge storing 2.8 million kWh. After commissioning, core equipment will be 100% domestically produced.

The phase-two project is built and operated by Huaneng Jiangsu company. The commissioning, conducted under real gas storage conditions using underground salt cavern resources at a depth of 1,000 meters and reusing the cavern built in phase one, comprehensively tested the coordinated operation of compressors, expanders, heat storage and exchange systems and control systems.

During startup, key parameters including unit vibration, temperature and pressure were better than design values, fully verifying the localization level of the entire salt cavern energy storage system. Next, the project will carry out pre-grid-connection tests and integrated system commissioning.

Once operational, the project can store surplus renewable power during low-demand periods and deliver stable output during peak hours, with efficient peak-shaving and rapid response capabilities.

It will boost renewable energy consumption in the Yangtze River Delta region, help ensure the safe and stable operation of the power grid, and provide important support for China's new-type power system and energy security.