## 6 Simulation Results and Discussion
### Case 3: BESS versus PHES with TADP DRP
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**GBRT Algorithm** & **Error Metric** & \(\alpha_{gbr}=0.1\) & \(\alpha_{gbr}=0.3\) & \(\alpha_{gbr}=0.5\) \\ \hline \multirow{3}{*}{**Wind speed forecasts**} & MAE & (m/s) & 0.22 & 0.25 & 0.28 \\  & RMES & (m/s) & 0.27 & 0.33 & 0.39 \\  & \(r^{2}\) & & 0.96 & 0.94 & 0.92 \\ \hline \multirow{3}{*}{**Wind power forecast**} & MAE & kW & 35.03 & 39.52 & 44.33 \\  & RMES & kW & 47.98 & 55.69 & 62.83 \\  & \(r^{2}\) & & 0.96 & 0.94 & 0.92 \\ \hline \multirow{3}{*}{**Solar irradiance forecast**} & MAE & W/m\({}^{2}\) & 15.36 & 18.55 & 20.35 \\  & RMES & W/m\({}^{2}\) & 29.62 & 34.87 & 40.50 \\  & \(r^{2}\) & & 0.99 & 0.98 & 0.98 \\ \hline \multirow{3}{*}{**Photovoltaic power forecast**} & MAE & kW & 17.43 & 21.05 & 23.08 \\  & RMES & kW & 33.60 & 39.55 & 45.94 \\ \cline{1-1}  & \(r^{2}\) & & 0.99 & 0.98 & 0.98 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Forecasting results of GBRT model based on MAE, RSME and \(r^{2}\) considering three \(\alpha_{gbr}\) values: \(\alpha_{gbr}=\{\) 0.1, 0.3, 0.5 \(\}\). Figure 6: Comparison between the actual versus the predicted wind speed with one-hour-ahead rolling forecasting horizon using the GBRT model at \(\alpha_{gbr}=0.1\) (from 1/12/2018 to 5/12/2018). Figure 8a,b shows the Pareto front plots with TADP DRP considering BESS and PHES, respectively; and Table 6 summarizes the cost-benefits analysis for the BESS and PHES-based microgrid configuration. According to the results of optimal capacity sizing considering TADP DRP at LPSP=0%, it can be noted that adoption PHES-based configuration will results in about 30.23% investment costs reduction compared to the BESS-based. Hence, PHES-based microgrid is the most cost-effective microgrid configuration compared to the BESS-based microgrid design. For all the scenarios (case 1-3) investigated, it is seen that PHES gives the lowest investment cost on ESS compared to BESS. Thus, for a cost-effective long-term investment, it can be deduced that the selection of the PHES-based microgrid has a better economic prospect compared to BESS-based configuration. Techno-Economic Comparison for Each ESS Type Based on DRP Options at Maximum System Reliability (LPSP = 0%)  
In this section, different microgrid configurations based on the DRP options are evaluated based on the net investment cost for different ESS types. The prospect of each configuration in the long-term \begin{table}
\begin{tabular}{l c c c c c c c c} \hline \hline  & \multicolumn{2}{c}{**BESS-Based Microgrid**} & \multicolumn{4}{c}{**PHES-Based Microgrid**} \\ \hline
**LPSP** & **0\%** & **5\%** & **10\%** & **15\%** & **0\%** & **5\%** & **10\%** & **15\%** \\ \hline
**PV capacity (kW)** & 1424 & 1191 & 1210 & 1193 & 1858 & 1831 & 1842 & 1826 \\
**WT capacity (kW)** & 1871 & 2020 & 1878 & 1655 & 1513 & 1363 & 1204 & 1018 \\
**ESS capacity (kWh)** & 5603 & 1341 & 460 & 181 & 7494 & 7326 & 7121 & 6397 \\ \hline
**TPC (US 5)** & \(\mathbf{1.28\times 10^{7}}\) & \(\mathbf{9.82\times 10^{6}}\) & \(\mathbf{8.78\times 10^{6}}\) & \(\mathbf{7.83\times 10^{6}}\) & \(\mathbf{8.93\times 10^{6}}\) & \(\mathbf{8.38\times 10^{6}}\) & \(\mathbf{7.89\times 10^{6}}\) & \(\mathbf{7.34\times 10^{6}}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Techno-economic analysis for case 3. Figure 8: Pareto front plots for case 3. Figure 7: Comparison of the actual versus the predicted solar irradiances with one-hour-ahead rolling forecasting horizon using the GRBT forecasting model at \(\alpha_{gbr}\) = 0.1 (from 1/12/2018 to 5/12/2018). microgrid planning with the possibility of high renewable energy fraction is reflected in the net investment cost under each system configuration. Figure 9a,b shows the pareto front plots comparison, without and with DRPs, for BESS and PHES-based microgrid design, respectively. Table 7 summarizes the investment cost under each configuration and flexibility options.