News Release

ACC Vote Regarding UNSE Black Mountain Generating Station Expansion Project

Phoenix, Ariz. –  The Arizona Corporation Commission voted 4 – 1, with Commissioner Anna Tovar dissenting, to reverse the Arizona Power Plant and Transmission Line Siting Committee’s Order regarding an expansion project at the Black Mountain Generating Station operated by UNS Electric, Inc.  The Request by UNS Electric, Inc. for a Disclaimer of Commission and Committee Jurisdiction has been granted pursuant to A.R.S. 40-360, and this Decision is effective immediately.  The decision means that the Commission does not have mandatory jurisdiction over electric generating plants under 100 MW for line siting purposes, a result dictated by law. 

“There was a spirited discussion on this issue and the Commission devoted a lot of time considering the different perspectives, reaching the ultimate conclusion that the law as written left the Commission no choice but to disclaim jurisdiction,” said Executive Director Doug Clark.

To be clear, in this Decision, the Commission is not exempting UNS Electric, Inc., or any other utility, from environmental review.  UNS Electric, Inc. is still required to obtain several permits from state and local agencies, including the Arizona Department of Environmental Quality.  Additionally, the utility is still required to obtain a Certificate of Environmental Compatibility from the Commission for interconnection with related transmission lines.

This is the first request for a disclaimer of jurisdiction under the statute that has come before the Commission for application in which the matter was disputed.   Arizona Revised Statutes 40-360 was established as law in 1971.  The current commissioners acknowledged the potential for the law to be updated to add together separate name plated plants generating plant power and include non-thermal generating plants.  Ultimately, the legislature has authority over those types of policy decisions, not the Commission.   

All documents relating to this agenda item can be found in the Commission’s Online docket at and entering docket number L-00000F-24-0056-00230.

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