Section 6 Ancillary Services
IFM Procurement and Prices
Table 6.1 shows the monthly IFM average ancillary service procurement and Table 6.2 shows the monthly IFM average ancillary service prices.
In August the monthly IFM average procurement increased for non-spinning and regulation up, while decreased for regulation down and spinning reserves compared to the previous month. The monthly IFM average prices decreased for regulation down and increased for non-spinning reserves, regulation up, spinning reserves compared to the previous month.
| Month | Jul-2025 | Aug-2025 | Percent Change |
|---|---|---|---|
| Regulation_Up | 450 | 465 | 3.33% |
| Regulation_Down | 916 | 891 | -2.73% |
| Spin | 894 | 868 | -2.91% |
| Non-Spin | 822 | 991 | 20.56% |
| Ancillary Service | Jul-2025 | Aug-2025 | Percent Change |
|---|---|---|---|
| Non-Spin | $0.65 | $1.41 | 118.5% |
| Regulation_Down | $4.97 | $4.59 | -7.5% |
| Regulation_Up | $2.65 | $2.91 | 9.7% |
| Spin | $0.68 | $1.50 | 119.7% |
Figure 6.1 shows the daily IFM average ancillary service prices.
Day-ahead ancillary service prices were volatile in August. Prices for regulation up and regulation down are kind of similar from July to August, while there were large contingency reserve price several days several days around August 21st due to unexpected events.
Figure 6.1: IFM (Day-Ahead) Ancillary Service Average Price
Daily average ancillary procurement and prices in the real-time market (FMM) are shown in the Appendix.
Scarcity Events
The ancillary services scarcity pricing mechanism is triggered when the ISO is not able to procure the target quantity of one or more ancillary services in the IFM and real-time market runs. The scarcity events in this month are shown in Table 6.3 below.
| Date | Hour Ending | Interval | Ancillary Service | Region | Shortfall | Percentage of requirement |
|---|---|---|---|---|---|---|