For the Balancing Authority of Northern California (BANC), a positive experience with CAISO’s Western Energy Imbalance Market was a key factor in the decision to also join the ISO’s Extended Day-Ahead Market (EDAM).
Before joining WEIM in 2019, BANC had estimated its annual benefits of WEIM participation in the $7 million to $8 million range, according to General Manager Jim Shetler. But those estimates have been far exceeded, Shetler said March 26 during a joint meeting of the CAISO Board of Governors and the Western Energy Markets Governing Body.
BANC’s benefits for participating in WEIM were about $49 million in the third quarter of 2024 and $58 million in the fourth quarter.
“I’ve yet to have any … BANC participants complain about the fact that we are in EIM,” said Shetler, also a key member of the committee driving the efforts of the West-Wide Governance Pathways Initiative, which has been working to bring independent governance to CAISO’s markets. (See Pathways Initiative Receives Praise, Skepticism at Calif. Hearing.)
Shetler gave a short presentation during the joint meeting to explain BANC’s reasons for joining EDAM rather than SPP’s competing day-ahead market, Markets+.
BANC announced its intention to join EDAM In August 2023 and signed a formal implementation agreement in November 2024. (See BANC Moving to Join CAISO’s EDAM and BANC Signs Agreement to Join EDAM.)
Shetler said another positive outcome of WEIM participation was the market’s “support for reliability.” He noted that BANC tends to hit its daily peak in summer about 60 to 90 minutes earlier than CAISO.
“We’ve very actively seen the EIM manage that: Help provide us cost-effective resources during our peak and then redispatch our resources to support the ISO peak as we start to come down,” Shetler said.
In addition, WEIM participation has reduced renewable curtailments, and BANC has been able to maintain a good trading capability.
BANC participated in the development of EDAM and Markets+ but for the past two years has been simply monitoring Markets+ progress.
A Brattle Group analysis found BANC’s benefits from joining EDAM would be about $5.5 million a year – “not a huge benefit … but it was positive,” Shetler said.
And EDAM met other day-ahead market criteria for BANC. Shetler said independence and self-determination are “first and foremost.”
“Members to the maximum extent possible can retain their independent decision-making on key factors,” he said.
Transfer capability was another point in favor of EDAM. BANC has about 2,000 MW of transfer capability with the ISO footprint through seven or eight interconnection points, Shetler said.
BANC is a joint powers authority with six member agencies: Sacramento Municipal Utility District, Modesto Irrigation District, Roseville Electric, Redding Electric Utility, Trinity Public Utility District and the City of Shasta Lake.
