Executive Summary
The purpose of this report is to provide market participants a monthly summary of day-ahead and real-time markets performance for May, 2026. The key market performance highlights are presented here:
CAISO area performance:
Peak loads for the ISO area increased in May compared to the previous month.
The cumulative frequency of prices in FMM above $250/MWh decreased from 0.10 percent in April 2026 to 0.06 percent in May 2026, while the cumulative frequency of negative prices increased from 30.61 percent in April 2026 to 31.33 percent in May 2026. Average FMM DLAP prices increased for PGAE, SCE, VEA, while SDGE experienced a decrease relative to the previous month.
The cumulative frequency of prices in RTD above $250/MWh increased from 0.10 percent in April 2026 to 0.11 percent in May 2026, while the cumulative frequency of negative prices increased from 31.31 percent in April 2026 to 32.11 percent in May 2026. Average RTD DLAP prices across PGAE, SCE, SDGE, and VEA increased relative to the previous month.
The cumulative total congestion rent for interties increased from $2.06 million in April 2026 to $2.39 million in May 2026. The majority of the congestion rents in May accrued on NOB_ITC (37.3%) and IPPUTAH_ITC (36.6%). Congestion rent on NOB_ITC increased from $378,732 in April 2026 to $891,270 in May 2026, while congestion rent on IPPUTAH_ITC increased from $0 in April 2026 to $873,937 in May 2026.
Net Monthly Balancing Surplus in May was $13,581,925. The auction revenues credited to the balancing account for May were $5,321,830. As a result, the balancing account had a surplus of approximately $18.904 million compared to $12.740 million in the previous month, which was allocated to measured demand.
In May, the monthly IFM average procurement decreased for regulation up, regulation down, and non-spinning reserves, while increasing for spinning reserves compared to the previous month. The monthly IFM average prices increased for regulation up, regulation down, and non-spinning reserves, while decreasing for spinning reserves compared to the previous month.
The total bid cost recovery decreased from $12.64 million in April 2026 to $11.87 million in May 2026. Out of the total monthly bid cost recovery payment in May, the IFM market contributed 31.0 percent and RTM contributed 69.0 percent of the total bid cost recovery payment.
RTIEO increased from $2.41 million in April 2026 to $4.14 million in May 2026. RTCO decreased from $25.64 million in April 2026 to $18.68 million in May 2026.
The monthly exceptional dispatch uplift payments increased from $4,317,762 in April 2026 to $5,777,890 in May 2026.
The number of market disruptions decreased from 63 in April 2026 to 44 in May 2026. On May 1, there were 15 (8 FMM, 2 HASP, 5 RTD) disruptions.
The total volume of exceptional dispatch increased from 85,761 MWh in April 2026 to 99,776 MWh in May 2026.
The curtailment of renewable energy decreased in May 2026 compared to the previous month. Most curtailments continued to be solar.
Flexible ramping up uncertainty payment increased from $34,712 in April 2026 to $87,763 in May 2026. Flexible ramping down uncertainty payment increased from $24,321 in April 2026 to $88,117 in May 2026.
Western Energy Imbalance Market (WEIM) performance:
Total WEIM RTIEO increased from $0.30 million in April 2026 to $1.43 million in May 2026. Total WEIM RTCO increased from -$5.63 million in April 2026 to $2.05 million in May 2026.
The cumulative frequency of FMM ELAP prices above $250/MWh increased from 0.03 percent in April 2026 to 0.06 percent in May 2026. The cumulative frequency of negative FMM ELAP prices decreased from 25.94 percent in April 2026 to 21.53 percent in May 2026. The cumulative frequency of RTD ELAP prices above $250/MWh increased from 0.05 percent in April 2026 to 0.10 percent in May 2026. The cumulative frequency of negative RTD ELAP prices decreased from 27.98 percent in April 2026 to 24.44 percent in May 2026.
Total WEIM BCR increased from $0.40 million in April 2026 to $2.91 million in May 2026.
Total flexible ramping up uncertainty payment increased from $0.23 million in April 2026 to $0.38 million in May 2026.
Total flexible ramping down uncertainty payment increased from $38,647 in April 2026 to $198,463 in May 2026.
Total forecast payment decreased from $16,243 in April 2026 to -$1,048,548 in May 2026.
| Month | WEIM | FMM ELAP Prices | RTD ELAP Prices | Price Difference |
|---|---|---|---|---|
| 2026-05 | AVA | $12.85 | $12.81 | $0.04 |
| 2026-05 | AVRN | $12.16 | $11.28 | $0.88 |
| 2026-05 | AZPS | $8.14 | $8.92 | -$0.78 |
| 2026-05 | BANC | $16.70 | $16.71 | -$0.01 |
| 2026-05 | BCHA | $2.41 | $1.40 | $1.01 |
| 2026-05 | BHBA | $13.04 | $17.23 | -$4.19 |
| 2026-05 | BPAT | $12.46 | $11.56 | $0.89 |
| 2026-05 | EPE | $16.85 | $18.93 | -$2.08 |
| 2026-05 | GWA | $11.20 | $11.43 | -$0.23 |
| 2026-05 | IPCO | $12.67 | $12.50 | $0.17 |
| 2026-05 | LADWP | $5.10 | $7.14 | -$2.04 |
| 2026-05 | NEVP | $9.89 | $10.72 | -$0.83 |
| 2026-05 | NWMT | $12.51 | $13.82 | -$1.31 |
| 2026-05 | PACE | $13.02 | $17.09 | -$4.06 |
| 2026-05 | PACW | $12.08 | $11.58 | $0.50 |
| 2026-05 | PGE | $13.84 | $12.81 | $1.03 |
| 2026-05 | PNM | $8.67 | $9.50 | -$0.83 |
| 2026-05 | PSEI | $12.22 | $11.21 | $1.01 |
| 2026-05 | SCL | $16.24 | $14.22 | $2.02 |
| 2026-05 | SRP | $9.55 | $10.32 | -$0.77 |
| 2026-05 | TEPC | $10.08 | $13.51 | -$3.42 |
| 2026-05 | TIDC | $17.06 | $17.03 | $0.03 |
| 2026-05 | TPWR | $13.67 | $12.42 | $1.25 |
| 2026-05 | WALC | $8.03 | $9.46 | -$1.43 |