# Capacity-Operation Collaborative Optimization for Wind-Solar-Hydrogen Multi-Energy Supply System
## 5 Sensitivity Analysis  
The analysis examines the impact of SF size, CSP capacity, TES capacity, PV capacity, WP capacity, PEME capacity, HST capacity, and PEMFC capacity on the LCOE and CO\({}_{2}\) emissions of the system, highlighting the significance of capacity parameters in affecting these outcomes. Figure 10 presents the variation of system LCOE and CO\({}_{2}\) emission when the SF size changes. As the figure shows, the LCOE decreases initially and then increases as the SF size increases. This trend results from the low system investment associated with small SF sizes. As the SF size grows, the system investment gradually increases, leading to a corresponding rise in  
As illustrated in Figure 12, the LCOE of the system initially decreases and then increases with the increase in TES capacity. When the TES capacity exceeds 8 h, the LCOE gradually increases due to the increased system investment, which surpasses the increase in system power generation. On the other hand, the CO\({}_{2}\) emissions of the system gradually decrease with the rise in TES capacity. Although the system LCOE experiences a slight increase after TES capacity exceeds 8 h, the system CO\({}_{2}\) emissions continue to decrease, indicating that increasing the TES capacity can enhance the system's operational performance. However, since the TES capacity has a limit, the TES capacity of 20 h is optimal for the system capacity configuration. Figure 13 indicates the effect of installed PV capacity on the system performance. As depicted in the figure, the system LCOE decreases and then increases with the increase in PV capacity. When the PV capacity is 50 MW, the system has the best economy at this time. The CO\({}_{2}\) emissions of the system gradually decrease as the PV capacity increases because the system's power generation also increases correspondingly. However, it should be noted that excessive PV capacity can negatively impact the system economy, and the capacity of the PEME is fixed. Therefore, an excessively large PV capacity can exacerbate the system's abandonment phenomenon, resulting in unnecessary waste. Figure 11: LCOE and CO\({}_{2}\) emission of WSH-MES system with different CSP capacity. Figure 10: LCOE and CO\({}_{2}\) emission of WSH-MES system with different SF size. As shown in Figure 14, the system's LCOE gradually increases as the number of WT increases. Because the increase in the number of WT leads to a significant increase in system investment. However, the CO2 emissions decrease as the number of WT increases, as the power generation of the system increases to a certain extent. Combining Figure 13 with Figure 14, it becomes evident that wind farms can reduce CO2 emissions by about 25% compared to PV. Since the installed capacity of WP is approximately half that of PV capacity, WP can complement PV by generating electricity at night. It plays the role of supplementing PV power generation during the day and CSP and PEMFC power generation at night, making it an effective power generation option. As can be seen from Figure 15a, the LCOE of the WSH-MES system first decreases and then increases as the PEME capacity increases. Meanwhile, CO2 emissions first decrease and then level off, with an optimal solution found at a capacity of around 10 MW. Because PEME plays a crucial role in consuming the electricity stored on an abandoned wind and solar basis, producing hydrogen energy, and compensating for user load deficits through PEMFC generation. Figure 12: LCOE and CO2 emission of WSH-MES system with different TES capacity. Figure 13: LCOE and CO2 emission of WSH-MES system with different PV capacity. Figure 14: LCOE and CO2 emission of WSH-MES system with different WP capacity. Figure 15: LCOE and CO2 emission of WSH-MES system with different PEME, HST, and PEMFC capacity. In Figure 15b, the trend of LCOE and CO\({}_{2}\) emissions variation with HST capacity is similar to that of PEME. HST mainly functions as a hydrogen energy storage to complement the PEME.