The Imperial Irrigation District (IID) has signed implementation agreements to participate in the Western Energy Imbalance Market (WEIM) and the Extended Day-Ahead Market (EDAM), which is scheduled to launch in spring 2026.
According to IID, the decision is aimed at improving operational flexibility and aligning with evolving regional energy market practices. The utility cited factors such as potential cost reductions, system reliability improvements, and opportunities to modernize power management systems as motivations for participation.
“This is a significant step toward modernizing how we purchase and manage power,” said IID General Manager Jamie Asbury. “It gives us the ability to react more quickly to market conditions while maintaining our status as an independent energy Balancing Authority.”
With this move, IID becomes the first utility to commit to joining both of the California Independent System Operator (ISO)-operated markets. IID’s participation is expected to begin in 2028 and will include integration with all California balancing authorities participating in ISO markets.
Other utilities have also committed to join EDAM. The Turlock Irrigation District plans to participate, while four additional energy providers have signed implementation agreements. PacifiCorp and Portland General Electric are expected to enter the market in 2026. The Los Angeles Department of Water and Power, along with the Balancing Authority of Northern California—which includes the Sacramento Municipal Utility District—are scheduled to join in 2027.
The ISO and stakeholders have developed EDAM to expand on the framework of the WEIM, which has managed real-time, least-cost energy transactions since 2014. According to ISO data, WEIM participants have reported approximately $7 billion in cumulative cost savings and have collectively avoided over one million metric tons of greenhouse gas emissions.
The EDAM is intended to provide similar benefits in the day-ahead market, where most energy transactions take place, potentially increasing economic efficiency and system reliability for participating utilities.
