CAISO leaders staged a virtual “town hall” to stress the importance of a smooth rollout to the ISO’s Extended Day-Ahead Market in May and promise to address market seams issues.
“This is clearly a pivotal moment for the West,” CAISO CEO Elliot Mainzer said during the Feb. 4 event. “We have the opportunity to … drive further reliability and affordability benefits.”
EDAM is scheduled to launch in 2026 with PacifiCorp and Portland General Electric as its first two participants. As of late 2025, both utilities were on track to join EDAM on their planned entry dates in spring and fall, although the schedule is considered very tight and aggressive. (See ‘Aggressive’ EDAM Schedule ‘Going Smoothly’ for PacifiCorp, PGE.)
CAISO recently entered parallel operations with PacifiCorp, and Mainzer said both entities are “very excited” to take that step.
CAISO Vice President of Stakeholder Engagement Joanne Serina said stakeholders are “really at the heart of everything we do here at the ISO.”
“We have been on a journey to ensure stakeholder engagement,” Serina said. “We’ve been working on an approach … to create a stronger, more meaningful role for stakeholders.”
Serina reminded the audience that CAISO introduced stakeholder working groups into the scoping and development phases of initiatives at the ISO. This approach has further strengthened the stakeholder process by inviting stakeholders to provide comments directly, she said.
CAISO wants to remain “nimble” with stakeholder initiatives as EDAM begins. A high-priority initiative in 2025 dealing with congestion revenue allocation rules is an example of that nimbleness, Serina added. (See CAISO’s EDAM Scores Simultaneous Wins at FERC.)
CAISO COO Mark Rothleder focused on the importance of transmission connectivity as EDAM launches. The resource diversity in the West and strong transmission connectivity in the ISO’s real-time Western Energy Imbalance Market (WEIM) “helps us all at different times in different ways,” Rothleder said.
“The seamless transactions have also been tremendously successful in supporting grid reliability,” Rothleder said. “When one area of the footprint … is facing reliability concerns, another area of the footprint can seamlessly deliver energy through transmission and the market to help manage grid conditions.”
A larger market will have even more opportunities to enhance reliability and deliver economic benefits, he added.
“Increasingly, we have tremendous reliability benefits from seamless operation of WEIM crossing large, geographically diverse footprints,” Rothleder said. “Without the seamless operation of the market and efficient utilization of the transmission connectively, results of [extreme weather events] would have looked much different.”
EDAM extends market optimization to the day-ahead time frame, where the bulk of scheduling occurs as the market efficiently positions the resources to serve the forecasted demand across the footprint, Rothleder said.
“We anticipate the EDAM market design will continue to evolve [and be] informed by stakeholder input and by operational experience,” Rothleder said.
CAISO recently completed the EDAM market simulation phase with PacifiCorp. The market simulation phase is the pre-production testing phase where EDAM technologies are available for market participants to test and evaluate.
No ‘Plug-and-play’ Solution for Seams
The number of energy entities committed to or leaning toward EDAM represents about 50% of the load in the West, Rothleder said.
However, with some WEIM participants intending to leave the market to join SPP’s Markets+, coordination across market seams will be necessary, Rothleder said.
In the West, seams arrangements “should build upon the foundation of existing operating agreements and standards and procedures used to maintain reliability for the region,” Rothleder said. “Specifically, any new agreements must preserve system reliability, account for emergency conditions and be compatible with NERC and WECC requirements.”
Participants on both sides of the market seams must be treated in a “just and reasonable matter,” Rothleder said.
“A seam isn’t inherently a problem. It’s simply a place where two systems meet,” he said.
The shared goal of dealing with seams is straightforward. If a seam doesn’t need to exist, let’s avoid creating one, Rothleder said.
But when a seam is unavoidable — and it sometimes is — entities must focus on minimizing the impact of the seam. That means clarity in roles and responsibilities, transparencies in expectations and empathy in how to collaborate, he said.
It is important also to recognize that Eastern joint operating agreements are not plug-and-play solutions for the West, added Anna McKenna, vice president of market design and analysis at CAISO. In the East, these agreements are typically bilateral and encompass topics that in the West are addressed with standards, framework agreements and operating procedures, she said.
Overall, the town hall “showcases the progress the ISO has made to deliver reliability and economic benefits by coordinating and optimizing across the Western energy footprint,” Rothleder said.
“If we keep approaching our work with the same level of honesty, shared purpose and adaptability, we will continue to operate as a community. I am looking forward to seeing what we have built, and what we will build next, together,” Rothleder said.


