Vail to Tortolita 230 Kilovolt Transmission Line

Under an agreement with WAPA, TEP will upgrade infrastructure along a 64-mile stretch between TEP’s Vail Substation located southeast of Tucson and its Tortolita Substation located north of Marana in Pinal County.

TEP will purchase development rights from the Southline Project, a proposed transmission line designed to transmit electricity across southern New Mexico and southern Arizona. The agreement calls for TEP to upgrade an existing 115-kilovolt (kV) Western Area Power Administration (WAPA) line with a double-circuit 230 kV transmission line. When complete, TEP will own and operate one 230 kV circuit and WAPA will own and operate the other. Ownership of the transmission structures will be split between TEP and WAPA.

The project will interconnect with TEP’s energy grid at three locations. By constructing an additional circuit in conjunction with the upgrade of existing lines, TEP obtains transmission capacity parallel and adjacent to its existing 138kV system without the environmental, visual and cost impacts associated with building a separate line. The project calls for installing new steel monopoles to replace H-frame wood pole structures that are more than 50 years old.

TEP’s ownership of a 230kV circuit will reduce the need for required upgrades within TEP’s existing 138kV system.

The project is pending a final agreement with WAPA, a federal agency that markets and delivers hydroelectric power, transmission and related services in Arizona and other western states. Rebuilding of the WAPA-owned line was authorized under a National Environmental Policy Act permitting process that culminated in a Record of Decision issued by the Bureau of Land Management in April 2016. A link to the decision is available here.

Construction is expected to begin in September 2024. The line is expected to be in service by 2027.

The Arizona Corporation Commission voted on January 12, 2021 to approve Amendment of Decision 75978 allowing TEP to own one of the 230kV circuits.

• ACC Docket L-00000AAA-16-0370-00173
• Vail - Tortolita 230 Kilovolt - ACC Order Amending Decision No. 75978
• ACC Order Decision No. 75978

CEC Application

• CEC APPLICATION Compressed (71 mb)
• CEC APPLICATION Print version (104 mb)
• EXHIBIT A: LOCATION AND LAND USE MAPS
• EXHIBIT B: ENVIRONMENTAL REPORT
• EXHIBIT C: AREAS OF BIOLOGICAL WEALTH
• EXHIBIT D: BIOLOGICAL RESOURCES
• EXHIBIT E: SCENIC AREAS, HISTORIC SITES AND STRUCTURES, AND ARCHAEOLOGICAL SITES
• EXHIBIT F: RECREATIONAL PURPOSES AND ASPECTS
• EXHIBIT G: CONCEPTS OF PROPOSED FACILITIES
• EXHIBIT H: EXISTING PLANS
• EXHIBIT I: ANTICIPATED NOISE AND INTERFERENCE WITH COMMUNICATION SIGNALS
• EXHIBIT J: SPECIAL FACTORS
• SUPPLEMENT TO JOINT APPLICATION TO AMEND
  DECISION NO. 75978 PURSUANT TO A.R.S.

The Arizona Power Plant and Transmission Line Siting Committee voted to approve TEP's application to amend Decision 75978 and case no. 173 at a hearing held Dec. 1-3, 2020.

• Notice of Errata for Order Amending Decision No. 75978
• Line Siting Committee Recommendation of Approval for Amending Decision No. 75978
• Witness Summary
• Exhibits submitted in Line Siting Committee Hearing
• Supplemental Filing by Intervenor re: CEC Condition No. 34
• Line Siting Hearing transcript – Day 1
• Line Siting Hearing transcript – Day 2
• Line Siting Hearing transcript – Day 3