​On May 1st 2026, CAISO’s Extended Day-Ahead Market (EDAM) and accompanying Day-Ahead Market Enhancements (DAME) extend wholesale day-ahead operations across the historically regulated Western Interconnection.

EDAM follows a month after SPP’s expansion into the Western Interconnection with RTO West. With their competing Markets+ launching in 2027, Balancing Areas in the West are drawing lines to join SPP or CAISO’s constructs by the end of the decade.

​For batteries and renewables, these expansions introduce new market products, and increase the liquidity of bilateral contracting opportunities across the region.

​This article covers what investors need to know about EDAM’s launch: two new market products, larger cross-BA contracting opportunities, and the expected impact on price dynamics. The next article in the series will cover SPP and Markets+.

Key takeaways

• EDAM goes live May 1st 2026. PacifiCorp joins as the day-one participant, adding roughly 12 GW of generation across coal, gas, hydro, wind and solar.
• DAME adds two new day-ahead product pairs to CAISO's procurement stack: Imbalance Reserves Up and Down, and Reliability Capacity Up and Down.
• Day-Ahead pricing at generator nodes expands the range of capacity swaps and tolling agreements written against settlement points.
• Ancillary services stay siloed by Balancing Authority at launch. Resource Adequacy stays fragmented across CPUC RA for CAISO, and the optional Western Resource Adequacy Program (WRAP) for WECC BAs.

To learn how the Extended Day Ahead Market works, read CAISO’s presentation on DAME and EDAM.

PacifiCorp anchors EDAM at launch, with the timeline running to 2029

PacifiCorp joins as the EDAM’s day-one participant, adding roughly 12 GW of generation across coal, gas, hydro, wind and solar.

The first entrant operates two service territories. Pacific Power (PACW) covers Northern California, Oregon and Washington and is a net importer. Rocky Mountain Power (PACE) covers Utah, Wyoming and Idaho and is a coal-dominant net exporter. Two intra-PacifiCorp transfer points, Mona and Crag View, handle the bulk of EDAM-CAISO settlements at launch.