Recently, the Institute of Engineering Thermophysics, Chinese Academy of Sciences, has made significant progress in the research field of megawatt-level constant-pressure compressed air energy storage technology. The R&D team has for the first time in the world completed the experimental study on the dynamic characteristics of the energy release of a megawatt-level constant-pressure compressed air energy storage system under all working conditions. The centripetal expansion machine they developed achieved a power output of 1.39 megawatts, and the overall isentropic efficiency of the machine reached 88.28%. The relevant achievements were published in the authoritative international Journal in the field of Energy Storage, "Journal of Energy Storage" (2026, 147: 120349).
The development of offshore wind power and other Marine renewable energy sources is an important way for China to achieve its "dual carbon" goals. By the end of 2025, the global cumulative installed capacity of offshore wind power was approximately 89.2GW, with China ranking first in the world with a cumulative installed capacity of 52 gigawatts. Renewable energy sources such as wind and solar power have characteristics like intermittency and randomness. Offshore wind power has an anti-peak shaving feature and lacks active support from conventional power sources. There is an urgent need for new energy storage technologies to support the stable operation and reliable transmission of renewable energy power generation. Underwater constant-pressure compressed air energy storage utilizes a constant hydrostatic pressure to achieve constant-pressure energy storage and release, without the need for a cushion air. Its energy efficiency can reach up to 80%, making it an effective solution for the large-scale consumption of renewable energy along the coast. However, the lack of research on the dynamic characteristics of this technology is the core bottleneck for its large-scale engineering application.
In response to this technical bottleneck, the R&D team has developed the first megawatt-level constant pressure compressed air energy storage experimental platform in China, which can simulate a water depth of 700 meters and support the experimental research of key components and the entire machine system of constant pressure compressed air energy storage. This study reveals the dynamic regulation characteristics of power and rotational speed throughout the entire process of system startup, steady-state operation, and shutdown. It precisely characterizes the temperature/pressure changes at each stage of the expander's inlet and outlet, the pressure loss of the heat exchanger, and the temperature/pressure changes inside the constant pressure storage tank, filling the research gap in the dynamic characteristics of the energy release of megawatt-level constant pressure compressed air energy storage systems under all working conditions.
This research provides an empirical basis for megawatt-level constant-pressure compressed air energy storage systems. The control strategies and component-level performance indicators proposed in the study offer important references for the engineering design, optimization and large-scale application of this technology. The rapid regulation capability verified by the experimental system can effectively support the flexible peak shaving demand of the power grid, which is of great significance for promoting the large-scale grid connection and consumption of coastal renewable energy such as offshore wind power in China and building a new type of coastal power system.
This research was supported by the National Natural Science Foundation of China, the Youth Talent Support Program of the China Association for Science and Technology, the National Key Research and Development Program, and the Key Fund of the Key Laboratory of Long-Duration Energy Storage.
Source: Energy Storage Research and Development Center
