Capacity optimization and performance analysis of wind power-photovoltaic-concentrating solar power generation system integrating different S-CO2 Brayton cycle layouts

This study investigates a wind power-photovoltaic-concentrated solar power (WP-PV-CSP) system that incorporates different supercritical CO2 (S-CO2) Brayton cycle layouts to address grid-connected safety issues associated with solar and wind energy. Additionally, it aims to enhance the system's techno-economic performance. Notably, prior research has not explored the optimal capacity configuration of the WP-PV-CSP system or identified the most effective S-CO2 Brayton cycle layout for system optimization. Reasonable capacity allocation can guarantee the system's reliability and feasibility, while an appropriate operation schedule can better handle the problem of mismatch between output and demand, and capacity and operation interact with each other. Consequently, this paper proposes a bi-level capacity-operation collaborative optimization approach to optimize the system's main components' capacity and operation scheduling with the optimization objectives of levelized cost of energy (LCOE) and CO2 emissions. Moreover, it seeks to pinpoint the most advantageous S-CO2 Brayton cycle layout. The results demonstrate that employing the S-CO2 intercooling Brayton cycle as the CSP system's power cycle yields the WP-PV-CSP system's best techno-economic performance. Compared with the WP-PV-CSP system integrating the steam Rankine cycle, the LCOE, CO2 emissions, and power discard are reduced by 13.81%, 40.36%, and 37.06%, respectively, and the system efficiency experiences a noteworthy 36.36% increase. These findings comprehensively highlight the substantial techno-economic and environmental advantages of adopting the S-CO2 Brayton cycle. In summary, this research contributes valuable insights into optimizing WP-PV-CSP systems, explicitly addressing capacity and operational challenges, and underscores the potential benefits of selecting the S-CO2 Brayton cycle in advancing renewable energy solutions.