PacifiCorp became the first utility outside California to join the California Independent System Operator’s (CAISO) extended day-ahead market on Friday. The Portland-based utility operates across six states and owns the largest privately held transmission system in the West, making its entry a primary catalyst for regional grid integration.
Pooling power across state lines
By joining the market, PacifiCorp is pooling its generation and transmission assets with California’s largest utilities, including Pacific Gas & Electric and Southern California Edison. The CAISO system uses an automated model to optimize power flow across the region, selecting the lowest-cost generation to meet forecast demand. PacifiCorp expects the move to eventually save its customers $300 million annually by improving how electricity moves through the historically fragmented Western grid.
- New entrants. Portland General Electric has pledged to join the market in October 2026.
- Future expansion. Utilities in New Mexico and other parts of California are slated to join in 2027.
- Past success. The move builds on a 2014 imbalance market that has generated $8.6 billion in benefits for participants since its launch.
The conflict. While PacifiCorp is betting on California’s system, the Bonneville Power Administration (BPA)—which operates 75% of the Northwest’s high-voltage grid—opted to join a rival market called Markets+. This decision is currently being challenged in the Ninth Circuit Court of Appeals by environmental groups who claim the split will increase energy bills and decrease access to renewables.
The push for a more unified market follows warnings of a 9-gigawatt supply shortfall in the Northwest driven by surging industrial demand and extreme weather risks. Portland General Electric joins the CAISO market in October.
