Arizona G&T Cooperatives (AzGT) announced today their interest in pursuing a study to assess the benefits for its cooperative members, public power utilities and electric districts in joining the California Independent System Operator’s (CAISO) Extended Day-Ahead Market (EDAM). 

As an initial step in this process, AzGT and over 20 cooperative, public power utilities and electrical districts engaged with CAISO management in Arizona last month to review the potential benefits of joining EDAM for their customers that are a part of the Western Area Power Administration’s (WAPA) Desert Southwest Region balancing authority area.

AzGT is a member-owned, not-for-profit electric generation and transmission cooperative that represents approximately 70% of the load in WAPA’s balancing authority in the state of Arizona. WAPA Desert Southwest has been a participant in the California Independent System Operator’s Western Energy Imbalance Market (WEIM) since 2023.

“Today marks an important milestone for the Arizona G&T Cooperatives as we announce our interest in exploring CAISO’s EDAM to determine potential benefits for our customers across Arizona,” said Patrick Ledger, CEO at AzGT. “We look forward to continued engagement with CAISO to build on the benefits we have seen through participation in WEIM, and to support WAPA as it explores expanding its participation.”

Tracey LeBeau, CEO of the Western Area Power Administration, said, “WAPA’s market principles has been to consider the unique characteristics and needs of each region, prioritize reliability, and ensure market participation optimizes value for WAPA customers. In this spirit, we support Arizona G&T Cooperatives in this evaluation of EDAM for the benefit of WAPA Desert Southwest customers.”

EDAM is a voluntary day-ahead electricity market designed to deliver significant reliability, economic and environmental benefits to balancing areas throughout the West. It is scheduled to launch in 2026.

“We are honored to provide real-time energy market services for a diverse set of western utility partners, and excited to learn that AzGT intends to explore further benefits from the extended day-ahead market," said Elliot Mainzer, president and CEO of CAISO. WAPA and its customers bring critical resources and connectivity for many in the West, and we look forward to continuing the mutually beneficial partnership.”

To date, PacifiCorp and Portland General Electric have executed EDAM implementation agreements and intend to join the market in 2026. Several other balancing authorities have signaled or indicated their intent to join EDAM including the Los Angeles Department of Water and Power, the Balancing Area of Northern California (which includes the Sacramento Municipal Utility District), Idaho Power, NV Energy and BHE Montana.