Turlock Irrigation District’s board of directors voted on May 13 to join the Extended Day-Ahead Market, which the California Independent System Operator is launching next spring.
TID already has experience participating in an integrated regional energy market, having been a member of the ISO-managed Western Energy Imbalance Market since 2021. During that time, TID has saved $28 million in cumulative costs, according to a staff report presented at the May 13 board meeting.
“TID has had tremendous success in the Western Energy Imbalance Market and we are excited to build on this partnership and leverage the increased economic, reliability, and environmental benefits of the Extended Day-Ahead Market,” said TID general manager Brad Koehn. “TID’s continued alliance with the California Independent System Operator will enable the district to continue our stellar track record of providing reliable, affordable power to its customers.”
According to PCI Energy Solutions, the CAISO will launch EDAM in May 2026, with the goal of optimizing electricity trading and grid coordination across the western United States. The new market is designed to extend CAISO’s day-ahead trading mechanisms beyond California’s borders, allowing multiple western states to participate in a more integrated and efficient energy marketplace. The move is seen as a critical step in improving grid reliability, enhancing renewable energy integration, and reducing overall electricity costs.
Four other energy providers have already signed agreements to join EDAM. PacifiCorp and Portland General Electric will begin participating in 2026, while the Los Angeles Department of Water and Power, and the Balancing Authority of Northern California have signed agreements to join in 2027.
Other Western energy providers are likely to join in the near future. BHE Montana, PNM and NV Energy have notified the ISO of their intentions to join EDAM. Idaho Power has indicated that it is leaning toward EDAM as its preferred day-ahead market, and Arizona G&T Cooperatives has also announced that they are studying the benefits of joining EDAM, as have several other utilities in the West.
The ISO and its stakeholders have designed the day-ahead market to build on the proven track record of the WEIM. Just under $7 billion in cost-saving efficiencies have been delivered to the WEIM’s 22 participants across 11 Western states since the market began managing real-time, least-cost energy transactions in 2014. The market has also avoided more than one million metric tons of greenhouse gas emissions and continues to grow, with two additional participants expected to begin participating in 2026.
The EDAM has been designed to unlock those benefits for WEIM participants in the day-ahead timeframe, where the bulk of energy transactions occur, and the reliability, economic and environmental benefits will be even greater.
¬¬The California Independent System Operator is a non-profit that provides comprehensive grid planning, open and nondiscriminatory access to one of the largest networks of high-voltage transmission power lines in the world, and operates a $9 billion competitive electricity market.
The Western Energy Imbalance Market is a real-time wholesale energy trading market that enables participants anywhere in the west to buy and sell energy when needed.
Founded in 1887, TID is the oldest irrigation district in California and provides irrigation water and electricity to more than a quarter million customers in the Central Valley.
