## 6 Simulation and Analysis
### Cross-RIES Optimization Results and Analysis
#### 6.4.3 Four Carbon Emission Reduction Policy Scenarios  
In order to comprehensively study the impacts of different carbon emission reduction policies, based on market mechanisms, on the carbon emission behaviors of cross-RIES systems, this chapter sets up four specific scenarios for analysis, as shown in Table 11. \(\beta_{GC}\) and \(\beta_{CET}\) represent the control variables for the green-certificate-trading mechanism and the carbon-trading mechanism, respectively, with a value of 1 indicating the application of the respective policy and a value of 0 indicating no application of the respective policy. Figure 10 illustrates the simulated results of carbon emissions in the cross-RIES system in four carbon emission reduction policy scenarios in the context of green development. It compares the carbon emissions for HP-RIES and CP-RIES operating in the FEL mode, as discussed in Section 6.3. The results in Figure 10 show that in the four carbon-emission reduction policy scenarios, the carbon emissions in the cross-RIES system are ranked from the highest to the lowest as Reference-CRIES, GC-CRIES, CET-CRIES, and GC-CET-CRIES. The Reference-CRIES scenario fails to achieve the carbon-peaking target, while in the other scenarios, the carbon emissions of the entire system are significantly lower than the carbon-peaking target constraint because of the market-driven effects of carbon- and green-certificate-trading mechanisms. This finding aligns with the results of another study in the literature [37]. Furthermore, it can be observed that the carbon emissions in the GC-CRIES scenario are higher than those of the HP-RIES system operating in the FEL mode. By 2040, the carbon emissions in the GC-CRIES scenario approach the total carbon emission rights. The CET-CRIES and GC-CET-CRIES scenarios, which implement the carbon-trading mechanism, outperform the HP-RIES system operating in the FEL mode in terms of the emission reduction performance. This indicates that compared to the carbon-trading mechanism, the \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & **2020** & **2025** & **2030** & **2035** & **2040** \\ \hline Total carbon emission rights for cross-RIES (tons) & 4341 & 4349 & 4314 & 4234 & 4110 \\ Carbon emission rights for fossil energy subsystem (tons) & 2752 & 2721 & 2661 & 2558 & 2428 \\ Carbon emission rights for hybrid energy subsystem (tons) & 930 & 963 & 948 & 944 & 913 \\ Carbon emission rights for clean energy subsystem (tons) & 659 & 665 & 705 & 732 & 769 \\ \hline \hline \end{tabular}
\end{table} 
Table 10: Total carbon emission rights for the cross-RIES system and initial carbon emission right quotas for each sub-RIES in the green development scenario. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Scenario** & **Carbon Emission Reduction Policy** & \(\beta_{GC}\) & \(\beta_{CET}\) \\ \hline Reference-CRIES & None & 0 & 0 \\ GC-CRIES & Green-certificate-trading mechanism & 1 & 0 \\ CET-CRIES & Carbon-trading mechanism & 0 & 1 \\ GC-CET-CRIES & Green-certificate- combined with carbon-trading mechanism & 1 & 1 \\ \hline \hline \end{tabular}
\end{table} 
Table 11: Four carbon emission reduction policy scenarios. green-certificate-trading mechanism has limited inhibitory effects on carbon emissions and weaker emission reduction performance. Additionally, the carbon emissions of CP-RIES operating in the FEL mode are lower than the carbon emissions of the cross-RIES system in the four carbon-emission reduction policy scenarios. This demonstrates the positive impact of market-based carbon emission reduction policies on traditional fossil energy emissions. Among all the carbon emission reduction policy scenarios, the GC-CET-CRIES scenario exhibits the best emission reduction performance. Although its carbon emissions are higher than those of CP-RIES operating in the FEL mode during the period from 2020 to 2035, by 2040, the GC-CET-CRIES scenario's carbon emissions are lower than those of CP-RIES operating in the FEL mode.