Integrating Compressed CO₂ Energy Storage in an Integrated Energy System

The integration of an energy storage system into an integrated energy system (IES) enhances renewable energy penetration while catering to diverse energy loads. In previous studies, the adoption of a battery energy storage (BES) system posed challenges related to installation capacity and capacity loss, impacting the technical and economic performance of the IES. To overcome these challenges, this study introduces a novel design incorporating a compressed CO(2 )energy storage (CCES) system into an IES. This integration mitigates the capacity loss issues associated with BES systems and offers advantages for configuring large-scale IESs. A mixed integer linear programming problem was formulated to optimize the configuration and operation of the IES. With an energy storage capacity of 267 MWh, the IES integrated with a CCES (IES-CCES) system incurred an investment cost of MUSD 161.9, slightly higher by MUSD 0.5 compared to the IES integrated with a BES (IES-BES) system. When not considering the capacity loss of the BES system, the annual operation cost of the IES-BES system was 0.5 MUSD lower than that of the IES-CCES system, amounting to MUSD 766.6. However, considering the capacity loss of the BES system, this study reveals that the operation cost of the IES-BES system surpassed that of the IES-CCES system beyond the sixth year. Over the 30-year lifespan of the IES, the total cost of the IES-CCES system was MUSD 4.4 lower than the minimum total cost of the IES-BES system.