World’s first non-supplementary-fired salt cavern CAES plant clocks over 1,500 days of stable continuous operation

As of 24 July 2026, China’s first salt cavern compressed air energy storage demonstration facility, the 60 MW Zhongyan Jintan Salt Cavern CAES Power Station, has maintained steady continuous operation for more than 1,500 days.

The facility stands as the world’s first non-supplementary-fired salt cavern compressed air energy storage plant, and remains the only project of its kind in China operating stably under long-term commercial conditions. Since its grid connection, the station has delivered grid peak regulation services on more than 960 occasions, supplying over 650 million kilowatt-hours of peak-shaving electricity and cutting carbon emissions by more than 300,000 tonnes.

Drawing on mature underground engineering expertise and operational experience accumulated from the first-phase demonstration project, Zhongyan Salt Cavern Company under China National Salt Industry Group and Huaneng Jiangsu Energy Company are accelerating construction of the second-phase Jintan project, comprising two 350 MW generating units. Once commissioned, the facility will achieve an energy conversion efficiency exceeding 70 per cent, marking it the largest single-unit salt cavern energy storage project under construction nationwide with leading overall efficiency metrics.

Subsurface geological conditions vary widely across China, including differences in salt layer depth and interlayer distribution. Underground salt cavern engineering is highly customised, with refined geological assessment, adaptive engineering design and precise control of cavern dissolution processes decisive for sustained and reliable operation. China National Salt Industry Group launched research and development into comprehensive salt cavern utilisation back in 2005. In 2021, it set up China’s first specialised enterprise focused on salt cavern comprehensive utilisation, establishing a fully independent technical framework for underground engineering. The group has pioneered proprietary cavity-building technologies such as the unobstructed dissolution cushion dual-pipe method, cutting energy consumption for cavern construction by 20 per cent against the industry average and lowering overall construction costs by 15 per cent. Independent technical appraisal confirms these innovations have reached internationally advanced standards.

The team has filed a total of 130 patents for salt cavern underground engineering technologies, among which 102 are invention patents. Seventy-eight patents have been granted, including 51 invention patents. The enterprise has led and participated in formulating ten national, industrial and association standards, and received multiple industry accolades such as the First-Class Science and Technology Award issued by the Jiangsu Geological Society and the Second Prize for Progress in Petrochemical Science and Technology.

As the dedicated operational platform for salt cavern assets within China National Salt Industry Group, Zhongyan Salt Cavern Company will continue advancing research into underground engineering technologies. It will coordinate the development of multi-purpose underground spaces capable of storing electricity, natural gas, hydrogen and helium. Robust technological capabilities developed by the central enterprise will support national energy transition strategies and the layout of strategic resource reserves.