During its October 15, 2025 Open Meeting, the Arizona Corporation Commission approved new measures to strengthen oversight of the state’s electric transmission grid. Commissioner Rachel Walden voted in favor of holding utilities accountable for providing more detailed information to the Commission, beyond what has been required over the past 26 years.
Commissioner Walden stated, “Finding the least cost, most reliable model includes transmission, not just electricity generation. None of the answers from our state utilities today inspired any confidence in me that these issues are a priority. I am not convinced that additional build out of renewables, while also having to add firm capacity as well as back up generation, is saving Arizonans money. I know that Arizonans are concerned with these issues, especially as we head into accelerated growth in our state. The Commissioners, as elected by the public, are faced with these questions and comments almost daily, and our actions are held accountable to the public.”
Arizona utilities are required by law to file a Ten-Year Forecast for their transmission systems every two years. The latest assessment projects an annual growth rate of about 3% from 2024 through 2033—slightly higher than previous forecasts. As Arizona increases its use of renewable energy sources, the Commission noted that utilities will need to collaborate more closely with neighboring states’ utilities due to operational challenges from intermittent resources.
Commissioner Walden emphasized concerns about costs associated with supporting policies outside Arizona: “Arizonan’s will not bear the costs and impacts of supporting neighboring states’ Green New Deal policies.”
She further added: “Ensuring our utilities have sufficient generation capacity to serve our customers during peak demand along with a reliable transmission grid to handle that capacity is paramount. The Commission must ensure that any transmission or generation solutions to mitigate grid concerns, such as line congestion created by the interconnections from new generation sources, or offtakes from the grid by large customers such as data centers and hyperscalers, are borne by the creators of those grid concerns, not Arizona ratepayers.”
An amendment introduced by Commissioner Walden was unanimously approved. It requires utilities to submit confidential business reports on line congestion and projections for load growth areas within their systems. This aims to help the Commission better assess reliability and manage requests for new connections across Arizona’s transmission network.
Commissioner Walden also supported an amendment from Commissioner Lea Márquez-Peterson mandating utility reports on all efforts to enhance their grids—including reconductoring lines and hardening infrastructure.
“I will be watching the Biennial Transmission Assessments and Integrated Resource Plans closely, and investigating these issues in all future rate cases,” concluded Commissioner Walden.
