## 4 Case Study and Discussion
### Case Study
#### 4.2.2 Case Results
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{3}{*}{**Month**} & \multicolumn{3}{c}{**Average Value of Power Exceeding**} & \multicolumn{3}{c}{**Average Value of Power Exceeding**} \\  & \multicolumn{3}{c}{**the Lower Variation Criteria of PCC**} & \multicolumn{3}{c}{**the Lower Variation Criteria of PCC**} \\  & \multicolumn{3}{c}{**in the Off-Peak Period**} & \multicolumn{3}{c}{**in the Peak Period**} \\ \cline{2-10}  & **Case 1 \& Case 2 & Case 2-1 & Case 2-2 & Case 2-3 & Case 1 \& Case 2 & Case 2-1 & Case 2-2 & Case 2-3 \\ \hline
1 & 45.16 & 18.01 & 17.85 & 16.53 & 14.81 & 0 & 0 & 0 \\
2 & 27.37 & 6.07 & 10.31 & 3.02 & 0 & 0 & 0 & 0 \\
3 & 7.96 & 0 & 0 & 2.48 & 16.3 & 25.3 & 16.3 & 0 \\
4 & 17.9 & 14.38 & 20.7 & 7.74 & 19.35 & 19.35 & 0 & 0 \\
5 & 16.02 & 10.17 & 7.25 & 2.68 & 15.5 & 15.5 & 0 \\
6 & 8.72 & 8.08 & 0 & 12.02 & 19.48 & 18.58 & 18.85 & 41.12 \\
7 & 8.8 & 9.73 & 3.98 & 7.29 & 12.11 & 0 & 12.1 & 13.93 \\
8 & 8.47 & 11.02 & 8.24 & 7.89 & 61.67 & 61.29 & 33.62 & 18.43 \\
9 & 5 & 3.99 & 2.77 & 4.91 & 49.15 & 49.15 & 49.15 & 25.58 \\
10 & 12.88 & 5.6 & 12.45 & 10.73 & 29.58 & 24.18 & 31.01 & 0 \\
11 & 11.03 & 13.03 & 2.47 & 5.78 & 38.86 & 19.04 & 0 & 0 \\
12 & 31.57 & 21.95 & 21.53 & 16.96 & 17.87 & 34.51 & 19.88 & 0 \\ \hline Total & \multirow{2}{*}{16.74} & \multirow{2}{*}{10.17} & \multirow{2}{*}{8.96} & \multirow{2}{*}{8.17} & \multirow{2}{*}{24.56} & \multirow{2}{*}{22.24} & \multirow{2}{*}{16.37} & \multirow{2}{*}{8.26} \\ Average & & & & & & & (19.4\%) & (\(\downarrow\)33.3\%) & (\(\downarrow\)66.4\%) \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Monthly power exceeding the lower variation criteria of the point of common coupling (PCC) in off-peak and peak periods. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{3}{*}{**Month**} & \multicolumn{3}{c}{**Average Discharging Power**} & \multicolumn{3}{c}{**Average Discharging Power**} \\  & \multicolumn{3}{c}{**during Off-Peak Periods**} & \multicolumn{3}{c}{**during Peak Periods**} \\ \cline{2-10}  & **Case 1 \& Case 2 & Case 2-1 & Case 2-2 & Case 2-3 & Case 1 \& Case 2 \& Case 2-1 & Case 2-2 & Case 2-3 \\ \hline
1 & 0 & 163.8 & 158.5 & 160.5 & 182.4 & 182.9 & 172.8 & 130.2 \\
2 & 0 & 156.7 & 157.4 & 129.4 & 184.5 & 187.2 & 137.2 & 71.5 \\
3 & 0 & 160.6 & 161.1 & 161.3 & 182 & 179.9 & 155.5 & 161.7 \\
4 & 0 In the off-peak period, ESS operations rarely affected the average power shortage in cases 1 and 2. The results of case 2-1, when the ESS begins discharging power, showed that the shortage was significantly reduced during the winter months. Furthermore, these monthly results demonstrated unique increments. Although there was a slight lack of consistency in the results, the total average power shortages decreased by almost 39% for cases 1 and 2. Similarly, in cases 2-2 and 2-3, the average value of power exceeding the lower variation criteria decreased, and the total average power for cases 1 and 2 reduced by almost 47% and 51%, respectively. The trends in power exceeding the variation criteria in the peak period are similar to those in the other period. Although the amount of discharging power seemed greater during the peak period, as shown in Table 5, the average power shortage in cases 1 and 2 were relatively larger in the peak period than those in the off-peak period. The shortages had a high value during the summer months since the peak period was longer than in other seasons. Contrary to the case trend of a decreasing discharging power during the peak period, the average value of power shortages decreased. In short, although the REC multiplier in the peak period was unchanged, the number of power shortages tended to decrease. These results imply that changes in the off-peak period would result in changes in the peak period by discharging power when the wind power fluctuations are significant.