daily · Climate Policy

Arizona utility commissioner presses for proof that large loads pay their costs

In a November 8 interview published November 9, Lea Márquez Peterson discussed water use, electricity affordability and Western markets. Her views are not a new statewide tariff or a guarantee of lower household bills.

By Greener Numbers Editorial Team · Published November 9, 2026 · Updated 11/9/2026

Arizona Corporation Commission member Lea Márquez Peterson says customers want evidence that fast-growing electricity demand is paying its own costs. In an interview conducted November 8 and published by Utility Dive on November 9, she discussed large-load development, water use and electricity affordability. The interview records one commissioner's views, not a new commission order or an approved change to household rates.

Márquez Peterson said Arizona is seeing requests from large users including semiconductor businesses as well as data centers. Water use is leading the public discussion, she said, and some proposed developments have not been as transparent as they should be. Those comments establish her concern about disclosure; they do not establish that the commission has adopted a new mandatory water-use rule.

On electricity costs, she said customers are asking how the commission can show that growth is paying for growth. She identified rate design, supply agreements and allocation of costs to large loads as possible tools. Whether large users help pay for new generation was another question she raised, rather than an agreement announced in the interview.

Asked about a standardized large-load tariff, Márquez Peterson said there was no statewide initiative of that kind. She expected further development of large-load issues in upcoming utility rate cases. She also described herself as skeptical about formula rates and said she wanted proof that they would benefit customers, with individual cases still to be considered.

Western electricity-market participation is another area where she is seeking more information. She said the commission does not choose which regional market utilities join, but she wants to understand the cost-benefit analysis and effects on customers. She described a February 3 workshop as a chance to ask more questions about reliability, transmission availability and resource planning.

For households, the practical issue is how future agreements and rate proceedings assign the cost of serving new demand. The interview does not quantify a bill increase or reduction, approve a statewide tariff, or show that a particular project has met its obligations. Those outcomes depend on decisions and evidence beyond the commissioner's comments. Utility Dive says it edited the interview for length and clarity.