Conventional and advanced exergy analysis of a grid connected underwater compressed air energy storage facility

• Published in: Applied energy 2019-05, Vol.242, p.1198-1208
• Main Authors: Ebrahimi, Mehdi, Carriveau, Rupp, Ting, David S.-K., McGillis, Andrew
• Format: Article
• Language: English
• Subjects: Energy storage; Exergy analysis; Exergy destruction components; UWCAES
• ISSN: 0306-2619; 1872-9118
• DOI: 10.1016/j.apenergy.2019.03.135

•The world’s first grid connected UWCAES facility was thermodynamically analyzed.•Conventional and advanced exergy analyses were conducted.•The primary sources of energy loss were identified.•Conventional analysis showed that 47.1% of the exergy destruction was avoidable.•Advanced analysis revealed that 23.6% of the exergy destruction was unavoidable. A data driven exergy analysis has been conducted for the first known grid connected Underwater Compressed Air Energy Storage facility, located in Toronto, Canada. Further to examining the plant through conventional exergy analysis, results were enhanced by splitting exergy destruction rates into avoidable and unavoidable, as well as endogenous and exogenous parts via advanced exergy analysis. The conventional exergy analysis showed that under real operational conditions, the exergy destruction ratio was 47.1%, while under the theoretical unavoidable operational conditions it could be reduced to 15.9%. The overall outcome of the conventional exergy analysis was confirmed by the advanced exergy analysis, the details, however, were quite different. The results of advanced exergy analysis assigned the improvement priority to heat exchanger 4, followed by the turbine and the stage 3 compressor. Conversely, the conventional exergy analysis indicated that the total exergy destruction of the turbine was higher than that for heat exchanger 3. The advanced exergy analysis also revealed that 76.4% of the exergy destruction was avoidable, highlighting the significant potential of the system for performance improvement.