The world's largest salt cavern compressed air energy storage project, the Huaneng Jintan Phase II facility, has recently completed the full startup of its two generating units in Jintan District, Changzhou, Jiangsu Province. With equipment running stably, this milestone signifies a major breakthrough in China's large-scale compressed air energy storage core technology and complete system integration capabilities. The project's core equipment, the turbo-expander, was supplied by Dongfang Electric Corporation Dongfang Turbine Co., Ltd (Dongfang Turbine), a company based in Deyang, and its stable, superior performance has been crucial to the successful launch.
The "heart" of the Huaneng Jintan project is the non-combustion compressed air turbo-expander's medium-pressure module, as pictured in a photo provided by Dongfang Turbine. The industry often refers to salt cavern compressed air energy storage power stations as the power grid's "super power bank." In simple terms, this technology leverages vast, sealed underground salt caverns to store air: during the night when electricity demand and prices are low, excess power is used to compress air into the caverns; during peak daytime demand, the high-pressure air is released to drive turbines and generate electricity. This entire process requires no coal or oil and produces zero carbon emissions. It alleviates peak-time power pressure, better integrates renewable energy sources like wind and solar, and is a safe, long-lasting green energy storage method with promising prospects.
The Huaneng Jintan project is the first salt cavern compressed air energy storage power project in China and the world's first non-combustion compressed air energy storage generating unit. The entire system comprises two 350-megawatt units, making it one of the world's leading compressed air energy storage stations in terms of single-unit power, total capacity, and overall efficiency. The station can store up to 2.8 million kilowatt-hours of electricity per charge, is capable of approximately 330 charge-discharge cycles per year, and can respond to grid peak-shaving demands within minutes.
Where to Begin
The project's core component, the turbo-expander, was developed by Dongfang Turbine in collaboration with Tsinghua University, China National Salt Industry Group Co., Ltd., and China Huaneng Group Co., Ltd. It is an air turbine generator set specifically designed to match the characteristics of this energy storage station. The research team innovated the internal airflow channels to boost energy conversion efficiency and optimized the equipment's base structure to ensure faster, more stable installation. In 2020, the project's first air turbine rolled off the assembly line at Dongfang Turbine; in 2021, the unit was synchronized to the grid and generated the first kilowatt-hour from a large-scale domestic compressed air energy storage station; and in 2022, performance tests confirmed that the high-pressure and low-pressure cylinder efficiencies reached world-class levels. From the operation of a 60-megawatt unit to the successful launch of a world-class 350-megawatt unit, Dongfang Turbine has achieved a significant technological leap in the compressed air energy storage field, becoming the only expander manufacturer globally with a track record of two operating units.
The smooth startup of both units once again validates the robust capabilities of "Made in Deyang" major energy equipment. It also accumulates valuable practical experience for the widespread adoption and application of large-scale salt cavern compressed air energy storage across China.