Western Energy Markets Quarterly Benefits Report debuts with first Extended Day-Ahead Market results
FOLSOM, Calif. – The California Independent System Operator (CAISO) today released its inaugural Western Energy Markets Quarterly Benefits Report, an expanded publication that combines the longstanding Western Energy Imbalance Market (WEIM) quarterly benefits analysis with the first results from the ISO’s Extended Day-Ahead Market (EDAM). Reflecting the continued evolution of Western markets, the new report captures the value achieved through coordinated real-time and day-ahead market operations, providing a more comprehensive view of the economic, environmental and reliability benefits delivered to market participants across the region.
Since its launch in 2014, the Western Energy Imbalance Market total financial savings have, as of the second quarter of 2026, reached $9.08 billion for market participants and their customers. The Extended Day-Ahead Market delivered $11.38 million in benefits during its first two months of operation, shared among its first participants: PacifiCorp East, PacifiCorp West and CAISO. Like the WEIM early growth trajectory where financial savings grew substantially as new participants were added to the market and market footprint expanded, CAISO expects EDAM will follow a similar pattern.
"The Western electricity sector has entered a new era of regional collaboration," said Elliot Mainzer, president and CEO of the CAISO. "As participation in our energy markets continues to grow, this expanded quarterly report provides stakeholders with a clearer picture of the economic and reliability value these markets create for electricity consumers across the West.”
EDAM quarterly participant benefits
The report shows the following benefits for the Extended Day-Ahead Market, by participant, for the two months of operation in the second quarter:
Q2 2026 Gross EDAM Benefits by Participant (entry year)
| AREA | MILLIONS |
|---|---|
| California ISO (2026) | $5.96 |
| PacifiCorp East (2026) | $3.22 |
| PacifiCorp West (2026) | $2.2 |
| Total | $11.38 |
WEIM quarterly participant benefits
The report indicates that Western Energy Imbalance Market participants reduced their costs by $459.71 this quarter, bringing the total savings accrued since the market’s 2014 inception over $9 billion.
The report shows the following financial savings by participant:
Q2 2026 Gross Benefits by Participant (entry year)
| PARTICIPANTS | MILLIONS |
|---|---|
| Arizona Public Service (2016) | $13.87 |
| AVANGRID (2023) | $23.31 |
| Avista (2022) | $4.57 |
| Balancing Authority of Northern California (2019) | $40.67 |
| Black Hills (2026) | $2.50 |
| Bonneville Power Administration (2022) | $4.47 |
| California ISO (2014) | $26.75 |
| El Paso Electric (2023) | $1.80 |
| Idaho Power Company (2018) | $8.38 |
| Los Angeles Dept. of Water & Power (2021) | $64.91 |
| NV Energy (2015) | $72.23 |
| NorthWestern Energy (2021) | $27.89 |
| PacifiCorp (2014) | $43.49 |
| Portland General Electric (2017) | $11.79 |
| Public Service Company New Mexico (2021) | $40.89 |
| PowerWatch (2026) | $2.10 |
| Puget Sound Energy (2016) | $12.23 |
| Powerex (2018) | $0.98 |
| Seattle City Light (2020) | $15.08 |
| Salt River Project (2020) | $17.77 |
| Tacoma Power (2022) | $2.82 |
| Tucson Electric Power (2022) | $6.76 |
| Turlock Irrigation District (2021) | $0.81 |
| WAPA Desert Southwest Region (2023) | $13.64 |
| Total | $459.71 |
In addition to economic benefits, the report highlights market performance metrics including energy transfers, renewable energy integration, emissions reductions and other indicators that demonstrate the value of regional market coordination.
Read the full Western Energy Markets Quarterly Benefits Report.
###
About the California ISO
The California Independent System Operator (CAISO) is a nonprofit public-benefit corporation responsible for the reliable operation of California’s bulk electric grid. The ISO provides transmission planning, open and nondiscriminatory access to one of the world's largest high-voltage transmission networks and operates competitive wholesale electricity markets for the benefit of consumers.
About the Western Energy Markets
The Western Energy Markets include the Western Energy Imbalance Market (WEIM) and the Extended Day-Ahead Market (EDAM), which provide regional market coordination across the West. The WEIM, launched in 2014, helps participants balance electricity supply and demand in real time and has delivered more than $9 billion in benefits to market participants and their customers. EDAM began operation in 2026 and extends those benefits into the day-ahead timeframe through broader regional coordination. The Western Energy Markets Governing Body has primary decision-making authority over market rules specific to the WEIM and EDAM.