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 December the monthly IFM average procurement increased for regulation up, non-spinning and spinning, while decreased for regulation-down reserves compared to the previous month. The monthly IFM average prices decreased for regulation up, regulation down, spinning and non-spinning reserves compared to the previous month.
| Month | Nov-2025 | Dec-2025 | Percent Change |
|---|---|---|---|
| Regulation_Up | 530 | 602 | 14% |
| Regulation_Down | 953 | 887 | -7% |
| Spin | 710 | 734 | 3% |
| Non-Spin | 671 | 900 | 34% |
| Ancillary Service | Nov-2025 | Dec-2025 | Percent Change |
|---|---|---|---|
| Non-Spin | $0.72 | $0.69 | -4.9% |
| Regulation_Down | $4.02 | $2.59 | -35.4% |
| Regulation_Up | $1.73 | $1.32 | -23.8% |
| Spin | $0.77 | $0.69 | -10.5% |
Figure 6.1 shows the daily IFM average ancillary service prices.
Day-ahead ancillary service prices remained volatile in December, similar to the previous month.
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 |
|---|---|---|---|---|---|---|