California Grid Operator’s Extended Day-Ahead Market Generates $11.4 Million in First Two Months

The California Independent System Operator on July 30 released its first Western Energy Markets Quarterly Benefits Report, combining the long-running assessment of the Western Energy Imbalance Market, or WEIM, with the inaugural results from its Extended Day-Ahead Market, or EDAM. The expanded report provides a broader view of how coordinated real-time and day-ahead electricity trading is lowering costs, improving grid reliability, supporting renewable energy integration, and reducing emissions across the western U.S. The report found that cumulative financial benefits from WEIM have surpassed $9 billion since its launch in 2014, while the EDAM generated more than $11 million in benefits during its first two months of operation.

The new day-ahead market, which began operating in the second quarter of 2026, produced approximately $11.4 million in gross benefits for its initial participants: CAISO, PacifiCorp East, and PacifiCorp West. The grid operator expects those savings to increase as additional utilities join the market, mirroring the growth trajectory of the WEIM, whose economic value has expanded steadily as participation widened across the region.

The quarterly report also found that WEIM participants realized nearly $460 million in gross benefits during the second quarter alone. Nevada Energy, Los Angeles Department of Water and Power, PacifiCorp, Public Service Company of New Mexico, and the Balancing Authority of Northern California were among the largest beneficiaries during the period, reflecting the value of broader regional coordination in balancing electricity supply and demand. In 2025, WEIM generated about $1.62 billion in economic benefits for participating utilities, underscoring the continued value of regional electricity market coordination.

Beyond financial savings, the publication highlights operational improvements resulting from expanded market coordination. The report identifies increased energy transfers, stronger integration of renewable generation, lower emissions, and enhanced grid reliability as key outcomes of regional electricity trading. By combining results from both real-time and day-ahead markets in a single publication, CAISO aims to provide utilities, regulators, and other stakeholders with a more comprehensive assessment of the economic and operational benefits delivered through growing regional market integration across the western electricity system.