## 4 Numerical Results
### Case Studies and Discussions
#### 4.2.2 Evaluating the Impact of Reserve Activation Probability  
To evaluate the impact of reserve activation probability on the CVPP's schedule, this section considers Case 1, Case 2, and Case 3 with reserve activation probabilities of 2%, 5%, and 10%, respectively. The other input data in these two cases is kept the same as in the base case.  
In the base case, RESs' power output at 11:00-15:00 is much higher than the local demand, which means it is very favorable for CVPP to provide an upward reserve (Figure 8). However, the amount of reserve energy, including both upward and downward reserve, in this period is much smaller than in the rest of the day. In detail, at 11:00-12:00 and 14:00-15:00 with the BC contract, CVPP only provides the minimum upward reserve required by the BC contract, and from 12:00-14:00 without the BC contract, the upward/downward reserve is even less than 2 MW (Figure 10b). This can be explained by the fact that the reserve activation probability is only 1%, so low that even though the BE price is more attractive than the DA price, CVPP still does not have much expectation of profiting from the BE market. Meanwhile, the DA price in this period is quite high, more than 60 USD/MWh, so CVPP focuses on earning profits from selling the RESs redundant production to the DA market. On the contrary, during the remaining time of the day, when CVPP has to buy electricity from the system or the DA price is very low, CVPP increases the reserve energy level and expects profits from arbitrage opportunities in the BE market.  
Figure 14 presents the CVPP's trading strategies in the BE market in these above cases of reserve activation probability. Compared with the base case in Figure 10b, it can be seen that as the reserve activation probability increases, the reserve energy of CVPP also tends to increase, especially during noon. In detail, the CVPP's reserve power at 11:00-15:00 is not higher than 3 MW in the base case. During the same period, the CVPP can provide an upward reserve of up to 5 MW and 7 MW in Case 1 and Case 2, respectively. In Case 3, when the reserve activation probability is 10%, the upward/downward reserve power provided by the CVPP can reach about 10 MW. The data compiled in Table 3 also clearly shows the impact of reserve activation probability on the operating plan and the profit of CVPP. In the base case, the CVPP provides 109.54 MWh of upward reserve energy and 96.57 MWh of downward reserve energy. Then, the CVPP can obtain 612.69 USD from the DA market and 6374 USD from the BE market. However, it should be noted that the profit of 6374 USD is only CVPP's expectation if its trading strategy in the BE market is accepted and fully activated. As the probability of activating the reserve increases, CVPP's expectation of profit from the BE market also increases, causing CVPP's capacity distribution to shift gradually from the DA market to the BE market. Consequently, when moving from the base case to Cases 1, 2, and 3, the total upward/downward reserve energy and the expected profit in the BE market increase, whereas the DA profit decreases significantly.  
Figure 14: The CVPP’s trading strategy in the BE market is in (**a**) Case 1, (**b**) Case 2, and (**c**) Case 3.