## 5 Case Studies
### Simulation and Analysis of Results  
In this subsection, we investigate the proposed bidding strategy to the day-ahead energy market, with two case studies that are studied and analyzed. It should be mentioned that the gas-fuel consumption of GFUs is limited and the application of P2G conversion technology has solved this limitation to produce the electric power by GFUs without any reduction in their gas consumption. Therefore, these simulation processes have been categorized into two different cases. Case 1 indicates that the bidding strategy problem is investigated with GFU and WPU facilities, along with the limitation constraint of natural-gas consumption. However, in Case 2, introducing and applying P2G technology coupled with the two mentioned facilities produces more electric power from GFU by converting extra \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multicolumn{2}{c}{**GFU Facility**} & \multicolumn{2}{c}{**GSS Facility**} & \multicolumn{2}{c}{**P2G Facility**} \\ \hline
**Parameters** & **Values** & **Parameters** & **Values** & **Parameters** & **Values** \\ \hline \(P^{GF,Min}\) (MW) & 20 & \(\eta^{th,GSS}\) (\(\%\)) & 0.8 & \(\eta^{P2G}\) (\(\%\)) & 0.8 \\ \hline \(P^{GF,Max}\) (MW) & 100 & \(\eta^{dis,GSS}\) (\(\%\)) & 1 & \(P^{P2G,Min}\) (MW) & 5 \\ \hline \(T^{\text{ON}}\) (h) & 3 & \(G^{ch,GSS,Min}\) (MW) & 5 & \(P^{P2G,Max}\) (MW) & 30 \\ \hline \(T^{\text{OFF}}\) (h) & 3 & \(G^{ch,GSS,Max}\) (MW) & 30 & \\ \hline \(I^{\text{ON}}_{i=0}\) (h) & 0 & \(G^{dis,GSS,Min}\) (MW) & 5 & \\ \hline \(I^{\text{OFF}}_{i=0}\) (h) & 2 & \(G^{dis,GSS,Max}\) (MW) & 30 & \\ \hline \(R^{up}\) (MW/h) & 30 & \(A^{Min}\) (MWh) & 0 & \\ \hline \(R^{dn}\) (MW/h) & 30 & \(A^{Max}\) (MWh) & 100 & \\ \hline \(a\) (MBtu/MWh) & 10 & & & \\ \hline \(b\) (MBtu/h) & 2 & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Required parameters of GFU, P2G, and gas storage system (GSS) facilities [15]. Figure 3: The forecasted electricity market price [51]. wind power to natural gas. These two cases are briefly denoted as follows. Finally, a risk management methodology based on a robust approach is implemented to the presented optimization problem. 1. Determining the bidding strategy of GFU and WPU by considering the gas-fuel-consumption limitation. 2. Determining the bidding strategy of coupled GFU-P2G-WPU facilities by considering the gas-fuel-consumption limitation. **Case 1. ** In this case, two states of GFU's power production with and without limitation of gas fuel consumption are considered. These situations affect the whole obtained profit by the introduced hybrid system and the imported gas. At first, the dispatched power of GFU is shown in Figure 4. It should be noted that the foremost priority to dispatch is the free energy of WPU. Then the remaining capacity of the transmission line will be filled with optimal power dispatch of GFU. In the situation of gas-fuel limitation, the sold power to the energy market in high price hours (i.e., hours 19-21) is equal to the maximum capacity of the transmission line. Thus, when this limitation is removed, GFU's generated power in the medium price hours (i.e., hours 15-18) increases to reach the maximum value of the transmission line, depicted in Figure 4. Moreover, as can be observed in this figure, the generated power in the presence of gas-fuel limitation in hour 15 is less than the power in status without any restriction, which is due to the limitations of transmission line capacity and gas fuel. The generation of GFU mainly depends on the electricity price and wind power. During hours 5-12, GFU is offline due to low electricity prices and high wind-power penetration. However, during initial hours and after hour 12, since wind power reduces and the transmission line's capacity is empty, the GFU is online. Until hour 21, the GFU still online and at the final hours is getting offline due to a reduction in electricity price and an increase in wind power. In Figure 5, the forecasted and dispatched power of WPU are illustrated.