California ISO secures Portland General Electric’s formal commitment to join the Extended Day-Ahead Market

FOLSOM, Calif. – FOLSOM, Calif. – Portland General Electric (PGE) is now the second entity in the Western United States to sign an implementation agreement and formally commit to a regional day-ahead energy market with the California Independent System Operator (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. The remaining tariff changes allowing the EDAM were accepted by the Federal Energy Regulatory Commission in June, and the market is on track to become operational in 2026.

“Portland General Electric has been an excellent partner in our real-time electricity market and has been very engaged in our work with stakeholders to design the extended day-ahead market,” said Elliot Mainzer, the ISO’s president and CEO. “PGE’s formal commitment to join EDAM provides more positive momentum for building a fully integrated Western day-ahead market that will benefit all market participants and their customers.”

PGE serves 1.9 million customers in Oregon with a peak load of nearly 5,000 megawatts. In March, it announced its intention to join the EDAM, extending the success of the ISO’s Western Energy Imbalance Market (WEIM), a real-time wholesale energy market that has produced cost savings to PGE customers and other market participants. By joining EDAM, Portland General Electric will have greater access to lower-cost renewable energy resources that are available from a more geographically diverse system.

Established in 2014, the WEIM 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 energy imbalances throughout the West by transferring energy between participants in 15-minute and 5-minute intervals throughout the day. The EDAM builds on this real-time market by expanding the commitment of least-cost generation across the market’s broad geographic footprint that are made a day in advance, unlocking far greater market efficiencies and value.

The implementation agreement is a provision of the ISO tariff and became effective upon the signing of both parties on June 28, 2024. PGE is expected to begin participating in the EDAM in fall 2026.

In addition to PGE, PacifiCorp has signed an agreement to begin participation in the EDAM in spring 2026. Three additional entities have informed the ISO of their interest in joining the EDAM: Balancing Authority of Northern California, Los Angeles Department of Water & Power and NV Energy. Idaho Power has said it is leaning toward the EDAM as its preferred day-ahead market.

For more information, visit our EDAM webpage on the Western EIM website .