Performance analysis of a novel medium temperature compressed air energy storage system based on inverter-driven compressor pressure regulation

In a significant advancement for renewable energy storage, researchers at the State Grid Hubei Electric Power Testing Research Institute (China), in collaboration with the China Energy Digital Technology Group Co., Ltd., and the Huazhong University of Science and Technology, have developed a novel medium-temperature compressed air energy storage (CAES) system. This system utilizes inverter-driven compressor pressure regulation, offering a viable solution for optimizing CAES systems and enhancing their round-trip efficiency by 3.64%.

The global context of fossil fuel scarcity and global warming has accelerated the development of renewable energy sources, with wind and solar energy leading the way. However, the intermittency of these sources and their integration challenges have resulted in significant economic losses due to curtailed power. Energy storage technologies, particularly CAES, play a crucial role in balancing supply and demand, maintaining grid stability, and reducing energy waste. Despite its advantages, the current system efficiency of practical CAES implementations remains at approximately 70%, highlighting the need for improved cycle efficiency to reduce generation costs and enhance market competitiveness.

The research team proposed a novel scheme for a CAES system that employs an inverter-driven compressor for pressure regulation, effectively replacing traditional throttle valves. The system and a reference system were evaluated through exergy analysis, dynamic characteristics analysis, and various other assessments. The performance analysis was conducted based on key parameters such as thermal storage temperature, component isentropic efficiency, and designated discharge pressure.

The novel system demonstrated a relative improvement of 3.64% in round-trip efficiency compared to the reference system, showcasing its capability to enhance efficiency without significantly increasing system complexity. The results indicated that the system's flexibility in adapting to internal pressure variations contributes to more effective energy conservation, making it a promising solution for optimizing CAES systems.

This research holds significant implications for the renewable energy sector by addressing the limitations of traditional CAES systems. The proposed system not only improves the work capacity of air by elevating the maximum air storage pressure but also reduces exergy losses associated with system throttling. The adoption of the stepped carbon trading strategy ensures the economic operation and energy utilization efficiency of the PIES while motivating the energy station and users to participate in carbon reduction efforts. The research contributes to the global effort towards a more sustainable energy future by optimizing the operation of integrated energy systems and promoting environmental sustainability.