Dive Brief:
- In comments filed with the California Independent System Operator about recent performance data for its Extended Day-Ahead Market, several commenters — including staff from the California Public Utilities Commission’s Energy Division — highlighted seeming data discrepancies or unclear methodology, and asked CAISO to publish more of the methodology behind its conclusions.
- CPUC staff noted in comments filed Aug. 12 that “it is not clear why CAISO made a 592.50 MW load adjustment” on June 11, and questioned the math behind CAISO’s adjustment of 3,590 MW on Aug. 4.
- California’s “Six Cities” of Anaheim, Azusa, Banning, Colton, Pasadena and Riverside filed Aug. 13 comments asking for an ongoing cost-benefit analysis for EDAM, citing the “extremely high resource commitments” made by CAISO and market participants, as compared with the “negligible benefits” of the market in its first two months.
Dive Insight:
CAISO’s EDAM, the first Western day-ahead market, launched in May. PacifiCorp was EDAM’s inaugural non-CAISO participant and is still its only one, but is set to be joined by Portland General Electric on Oct. 1.
“EDAM gross benefits for May and June totalled $11.38 million for the entire market. Of the total amount, gross benefits to the CAISO BAA were $5.96 million,” the Six Cities wrote. “However … the CAISO BAA transferred $2.67 million in congestion revenues to PacifiCorp, amounting to about 45% of the attributed gross benefits.”
The Six Cities wrote that “a comparison of costs and benefits accruing to the [Balancing Authority Areas] participating in the EDAM and the [Western Energy Imbalance Market] should guide the allocation of responsibility for market costs going forward. Benefits received from participating in either or both of the EDAM and WEIM should be at least roughly proportional to responsibility for market costs.”
CPUC staff’s comments questioned CAISO’s math in making load adjustments on June 11 and Aug. 4 in response to a deficiency of Imbalance Reserve Up capacity. CPUC staff wrote that it understands CAISO’s operating procedure requires it to “procure 100 percent of the IRU requirement at the 97.5 percent level when load exceeds 42,000 MW, but the day-ahead load forecast for June 11th was 37,000 MW.”
“Therefore, it would be helpful if CAISO could explain the reason for the [Residual Unit Commitment] load adjustments on June 11th, specifically for [hour fourteen], but for the other hours as well,” CPUC staff wrote.
The Aug. 4 adjustment also “[seemed] larger than one would expect,” said CPUC staff.
At the time, it appeared the system was “fully resourced” to meet the published requirement by covering 90% of potential outcomes, but even with CAISO covering more of its uncertainty by procuring enough load to meet 97.5% of outcomes, the additional 3,590 MW is “four times as much of the requirement,” CPUC staff said.
“It is difficult to understand how moving from the 90 percent uncertainty to the 97.5 percent uncertainty would increase the requirement nearly fivefold (i.e., from ~900 MW to 4,400, or ~900 MW + ~3600 MW),” staff wrote.
“I think the strongest element of Energy Division's comments is that currently available public data don’t allow stakeholders to reproduce the calculations behind some of the CAISO's key results,” energy and regulatory analyst Michael Cade wrote in comments to Utility Dive. “That discrepancy alone doesn't show that the adjustments were wrong. CAISO uses a separate, higher uncertainty benchmark to calculate them.”
“Energy Division's concern is that the published data don't show how that calculation produced adjustments of 592.5 MW and 3,590 MW,” he said.
Cade said that “a similar concern applies” to the Six Cities’ comments questioning CAISO's $11.38 million EDAM benefits estimate. “CAISO reports the total and its allocation among the three participating balancing areas, but not the underlying counterfactual results or a dollar breakdown by benefit component,” he said.
In CPUC staff’s comments, it noted that CAISO “indicated” in a previous meeting that it had run a counterfactual “comparing the CAISO day-ahead market results with the EDAM day-ahead market results,” and asked CAISO to share those results at the next Market Performance and Planning meeting.
Powerex Corp., a marketer of wholesale electricity, submitted Aug. 14 comments asking CAISO to report “congestion revenue based on the area where market participants paid the congestion cost.” Currently, it is “unclear how much of the $37.6 million in congestion revenues associated with constraints in the California ISO BAA were paid by market participants in PacifiCorp West and in PacifiCorp East,” the company wrote.
These stakeholder comments were submitted in response to CAISO's Market Performance and Planning Forum Q3 meeting on July 30. CAISO’s Market Performance and Planning Forum Q4 meeting is “tentatively” scheduled for Oct. 29, according to the ISO’s website.
