# Capacity-Operation Collaborative Optimization for Wind-Solar-Hydrogen Multi-Energy Supply System
## 6 Conclusions  
This research introduces a WSH-MES system, integrating a wind farm, PV power station, CSP power station, and hydrogen energy network at the grid level for the co-generation of hydrogen and thermal energy. A sophisticated bi-level-capacity co-optimization model was formulated to concurrently optimize large-scale equipment capacity and annual load dispatch. To tackle this intricate bi-level optimization challenge, a nested algorithmic approach employing LP and the NSGA-II was deployed. The optimal compromise solution is also found using a combination of TOPSIS and AHP-entropy allocation methods. Focusing on a WSH-MES system in Zhangbei, China, and incorporating uncertain weather data and electricity demand profiles, the proposed optimization strategy yielded a Pareto-optimal solution. This solution features an LCOE of USD 0.31/kW and CO\({}_{2}\) emissions of 630 t/y. Key parameters such as \(N_{\text{loops}}\), CSP capacity, TES capacity, PV capacity, number of WT, PEME capacity, HST capacity, and PEMFC capacity were optimized to 456, 55 MW, 20 h, 133 MW, 51, 10 MW, 7.144 m\({}^{3}\), and 5 MW, respectively. The economic analysis revealed that each 1% reduction in CO\({}_{2}\) emissions led to a 1.7% increase in the system's LCOE, underscoring the economic trade-offs involved in carbon mitigation. The optimized WSH-MES system demonstrated substantial reductions in annual WP and PV curtailment, as well as CO\({}_{2}\) emissions, compared to a reference system. The sensitivity analysis indicated that the LCOE of the WSH-MES system exhibited a non-linear response to changes in various capacities, with PV installed capacity emerging as the most significant factor affecting maximum CO\({}_{2}\) emissions. In future endeavors, the model and framework delineated in this paper will undergo refinements to incorporate dynamic energy flow characteristics, user behavior, stochastic distributed power output, and the influence of heat and hydrogen storage on system operation. These enhancements aim to bolster both the practical applicability and reliability of the study's conclusions. Conceptualization, L.L. and R.Z. ; methodology, L.L. and Y.H. ; software, L.L., Y.H. and Y.X. ; validation, Y.H., Y.X. and C.S. ; formal analysis, L.L. and Y.H. ; investigation, L.L., Y.X. and C.S. ; resources, R.Z. ; data curation, Y.H. ; writing--original draft preparation, L.L., Y.H. and Y.X. ; writing--review and editing, R.Z. ; visualization, L.L., Y.H., Y.X. and C.S. ; supervision, R.Z. ; project administration, H.Y. and Q.W. ; funding acquisition, R.Z. All authors have read and agreed to the published version of the manuscript. This research was funded by the National Natural Science Foundation of China grant number (No. 52090060). And The APC was funded by (No. 52090060). **Institutional Review Board Statement:** Not applicable. **Informed Consent Statement:** Not applicable. **Data Availability Statement:** The data presented in this study are available on request from the corresponding author. The data are not publicly available due to privacy restriction. **Conflicts of Interest:** The authors declare no conflict of interest.