PacifiCorp formally commits to California ISO’s EDAM


Partnership signals focus on reliability and value for electricity customers

FOLSOM, Calif. – PacifiCorp became the first entity in the Western United States to formally commit to a regional coordinated energy market by signing an implementation agreement this week with the California ISO for its Extended Day-Ahead Market (EDAM). 

The EDAM is a voluntary day-ahead electricity market designed to deliver significant reliability, economic, and environmental benefits to balancing areas and utilities throughout the West. Tariff changes allowing the EDAM were approved by the Federal Energy Regulatory Commission in December 2023, and the market is on track to become operational in 2026. 

PacifiCorp, a Portland-based grid operator that serves customers in California, Idaho, Oregon, Utah, Washington, and Wyoming, was also the first to publicly announce its intent to join the EDAM in December 2022 to expand on benefits it currently realizes from participation in the ISO’s real-time Western Energy Imbalance Market (WEIM). 

“We are excited to formalize our agreement to become a participant in the EDAM,” said Cindy Crane, chief executive officer for PacifiCorp. “A modern, coordinated day-ahead market in the West is vital to optimizing the region’s energy resources so we can continue to provide reliable and affordable power to our 2 million electricity customers across six states.” 

“The momentum we are seeing for participation in the EDAM is very encouraging, and PacifiCorp’s formal commitment brings better definition to the vision of a regional day-ahead electricity market,” said Elliot Mainzer, president and CEO of the ISO. “This is a major piece of a truly collaborative effort to support reliability and affordability for electricity customers by leveraging resource diversity and transmission connectivity across the footprint of the Western grid. We now look forward to continue working with additional valued partners in the West to take the next steps in a fully integrated regional market.” 

The WEIM is a real-time energy market that was established by PacifiCorp and the ISO in 2014. It has produced more than $5.4 billion in cumulative economic efficiencies and enhanced reliability by leveraging transmission connectivity and resource diversity across a broad geographical footprint covering 22 entities in 11 states. The market now represents 79 percent of the electricity load in the Western Interconnection. 

WEIM participation has delivered more than $745 million in savings to PacifiCorp customers. 

The WEIM optimizes the energy imbalances throughout the West by transferring energy between participants in 15-minute and 5-minute intervals throughout the day. The proposed EDAM builds on this real-time market by expanding to a high volume of resource commitments made a day in advance, unlocking far greater market efficiencies and value. 

The PacifiCorp implementation agreement is a provision of the ISO tariff, and became effective upon signing of both parties on April 25. PacifiCorp is expected to begin participation in the EDAM in spring 2026. 

Currently, four entities have informed the ISO of their interest in joining the EDAM: PacifiCorp, Balancing Authority of Northern California, Portland General Electric, Los Angeles Department of Water & Power. A fifth entity, Idaho Power has indicated it is leaning toward the EDAM as its preferred day-ahead market. 

For more information, visit our newly launched EDAM webpage on the website


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California ISO | 250 Outcropping Way | Folsom, CA 95630 |

The California Independent System Operator (ISO) is a nonprofit public benefit corporation dedicated, with its partners, to continuous improvement and secure operation of a reliable grid operated for the benefit of consumers. It provides comprehensive grid planning, open and nondiscriminatory access to one of the largest networks of high-voltage transmission power lines in the world, and operates a $9 billion competitive electricity market. Recognizing the importance of the global climate challenge, the ISO is at the forefront of integrating renew able power and advanced technologies that w ill help provide a sustainable energy future efficiently and cleanly.  

The Western Energy Imbalance Market (WEIM) is a real-time wholesale energy trading market that enables participants anywhere in the West to buy and sell energy w hen needed. The WEIM Governing Body is the governing authority designed by regional stakeholders and has shared authority with the ISO Board of Governors to resolve rules specific to participation in the WEIM.

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