In a significant shift for energy markets in the western United States, utilities are grappling with decisions that could reshape how power is bought and sold across the region. At the heart of this transformation is the Western Energy Imbalance Market (WEIM), a platform where 80% of western utilities exchange electricity to address power shortages and surplus.
The California Independent System Operator (ISO) established the WEIM in 2014 and continues to oversee its operations. However, this governance model is facing scrutiny. Brian Turner, a senior director at Advanced Energy United, notes that many involved in the market are critical of California’s control.
“Besides just the kind of interregional rivalry that is pretty natural, the California ISO was created as a nonprofit corporation for the benefit of the state of California,” Turner said. “And its board of governors is appointed by the California governor and confirmed by the state senate.”
In response to these concerns, a coalition of utilities, including Arizona Public Service (APS), Salt River Project (SRP), and Tucson Electric Power, is planning to establish a new market, Markets+, under the Southwest Power Pool next year. This move, however, poses a risk: these utilities would lose over half of their trading partners.
Turner describes the potential impact: “You’d now be reduced to about 30% of the West as your trading partners. You’ve got less visibility, less connectivity to other utilities that can help you out when it’s 115 degrees in Phoenix and the power is just off the charts and you need some immediate assistance.”
Advanced Energy United, which supports policies to integrate renewable and advanced energy resources into the U.S. grid, has also engaged in efforts to modify the WEIM’s governance. Turner participated in the Pathways Initiative, which included Arizona Corporation Commissioner Kevin Thompson, aimed at transferring oversight to an independent entity.
The Pathways Initiative has succeeded, with California agreeing to cede control to the Regional Organization for Western Energy (ROWE) by January 1, 2028. This development has caught the attention of the Bonneville Power Administration, a major trading partner in the potential Markets+.
In a letter dated September 3 to ROWE, Bonneville’s administrator Travis Kavulla highlighted past advantages of Markets+ regarding governance but acknowledged recent legislative changes in California allowing WEIM to be overseen by a regional entity.
Should Bonneville choose not to join Markets+, Arizona’s utilities could see a further reduction in trading partners. Commissioner Lea Márquez Peterson has set a deadline for these utilities to explain the implications of Bonneville’s stance by Friday.
An APS spokesperson confirmed the utility’s intent to proceed with Markets+ and expressed eagerness to comply with Commissioner Peterson’s request.
