Executive Summary
The purpose of this report is to provide market participants a monthly summary of day-ahead and real-time markets performance for August, 2025. The key market performance highlights are presented here:
CAISO area performance:
Peak loads for ISO area decreased slightly in September compared to the previous month possibly due to lower temperature.
The cumulative total congestion rent for interties decreased from $2.35 million in August to $0.346 million in September. Majority of the congestion rents in September accrued on NOB_ITC(26.7%), MALIN500_ISL(45%) and IPPUTAH_ITC(28.3%). The congestion rent on MALIN500_ISL inter-tie decreased from $1.94 million in August to $155,565 in September, while corresponding value of NOB_ITC decreased from $408,938 in August to $92,411 in September.
In the congestion revenue rights (CRR) market, net Monthly Balancing Surplus in September was $3.49 million. The auction revenues credited to the balancing account for September were $6.293 million. As a result, the balancing account had a surplus of approximately $9.78 million compared to $9.99 million in the previous month, which was allocated to measured demand.
In September the monthly IFM average procurement increased for regulation up and regulation down, while decreased for spinning and non-spinning reserves compared to the previous month. The monthly IFM average prices decreased for regulation down, non-spinning reserves, regulation up, spinning reserves compared to the previous month.
The total bid cost recovery decreased from $14.1 million in August to $12.3 million in September. Out of the total monthly bid cost recovery payment for the three markets in September, the IFM market contributed 17.4 percent, RUC contributed 62 percent, and RTM contributed 20.6 percent of the total bid cost recovery payment.
RTIEO decreased from -$0.429 million in August to -$8.6 million in September. RTCO decreased from $31 million in August to $28.5 million in September.
The monthly uplift payments increased from $59,487 in August to $443,880. Uplift payment increase was mainly caused by planned transmission outages in September.
The number of market disruptions increased from 24 in August to 38 in September. On September 29th, there were 21 (16 RTD, 4 FMM and 1 HASP) disruptions due to implementation of a market software patch. On September 11, there were 4 (4 RTD) interval disruptions due to implementation of a market software patch.
The total volume of exceptional dispatch decreased from 59,078 MWh in August to 49,694 MWh in September. There was a spike on September 6 due to the planned transmission outage.
The curtailment of renewable energy increased in September compared to the previous month. Most curtailments continued to be solar.
Western Energy Imbalance Market (WEIM) performance:
Average Day-Ahead DLAP prices in PGAE increased relative to the previous month, while prices in SCE, SDGE, and VEA remained largely unchanged between August and September. Except for PGAE, average FMM DLAP prices decreased from the previous month, in line with the load decline described above.RTD DLAP prices on average decreased compared to the previous month, except for PGAE, aligning with the decrease in load discussed in the last section.
The monthly average ELAP prices in FMM and RTD for WEIM entities and the difference between the two (FMM minus RTD) are shown in Table 0.1 below.
The cumulative frequency of prices in FMM above $250/MWh increased from 0.042 percent in August to 0.13 percent in September, while the cumulative frequency of negative prices increased from 1.08 percent in August to 1.5 percent in September, correlated with an increase in renewable generation curtailment. The cumulative frequency of prices in RTD above $250/MWh increased from 0.0756 percent in August to 0.0781 percent in September, while the cumulative frequency of negative prices increased from 0.748 percent in August to 2.05 percent in September, correlated with an increase in renewable generation curtailment.
Total WEIM RTIEO increased from -$0.755 million in August to $0.371 million in September. Total WEIM RTCO decreased from -$1.93 million in August to -$6.07 million in September.
Total WEIM BCR decreased from $1.57 million in August to $1.46 million in September.
Total flexible ramping up uncertainty payment decreased from $0.179 million in August to $0.128 million in September.
Total flexible ramping down uncertainty payment increased from $16,422 in August to $18,984 in September.
Total forecast payment decreased from $0.177 million in August to $0.122 million in September.
| Month | WEIM | FMM ELAP Prices | RTD ELAP Prices | Price Difference |
|---|---|---|---|---|
| 2025-09 | AVA | $34.61 | $35.63 | -$1.02 |
| 2025-09 | AVRN | $38.31 | $37.30 | $1.01 |
| 2025-09 | AZPS | $30.63 | $32.37 | -$1.74 |
| 2025-09 | BANC | $48.11 | $47.94 | $0.17 |
| 2025-09 | BCHA | $33.68 | $33.52 | $0.16 |
| 2025-09 | BPAT | $40.54 | $39.21 | $1.33 |
| 2025-09 | EPE | $32.83 | $34.42 | -$1.59 |
| 2025-09 | IPCO | $34.16 | $35.20 | -$1.04 |
| 2025-09 | LADWP | $42.42 | $42.61 | -$0.19 |
| 2025-09 | NEVP | $32.71 | $34.12 | -$1.41 |
| 2025-09 | NWMT | $34.05 | $35.36 | -$1.31 |
| 2025-09 | PACE | $32.73 | $34.21 | -$1.47 |
| 2025-09 | PACW | $37.30 | $36.41 | $0.89 |
| 2025-09 | PGE | $37.71 | $36.56 | $1.14 |
| 2025-09 | PNM | $31.51 | $33.78 | -$2.27 |
| 2025-09 | PSEI | $38.71 | $37.25 | $1.46 |
| 2025-09 | SCL | $38.57 | $37.27 | $1.30 |
| 2025-09 | SRP | $31.50 | $33.24 | -$1.74 |
| 2025-09 | TEPC | $30.64 | $32.85 | -$2.21 |
| 2025-09 | TIDC | $51.31 | $51.13 | $0.17 |
| 2025-09 | TPWR | $38.31 | $37.13 | $1.17 |
| 2025-09 | WALC | $30.65 | $32.14 | -$1.49 |