PacifiCorp became the first entity in the Western United States to formally commit to a regional coordinated energy market by recently signing an implementation agreement with the California ISO for its Extended Day-Ahead Market.
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).
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.
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, CAISO said.
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.
