Conventional and advanced exergy analyses of an underwater compressed air energy storage system

A 2 MW underwater compressed air energy storage (UWCAES) system is studied using both conventional and advanced exergy analyses. The exergy efficiency of the proposed UWCAES system is found to be 53.6% under the real conditions. While the theoretical maximum under the unavoidable condition is 84.3%; showing a great potential for performance improvement. Even though there are quantitative differences between conventional and advanced results, both show that the final compressor stage has the highest potential for improvement. The advanced exergy analysis reveals the real improvement potential of the UWCAES system. Further, it is revealed that the interactions between system components are complex but not very strong. Subsequently, the total exergy efficiency may not necessarily increase by improving the performance of the components individually.