Rio Rico-Harshaw 138kV Transmission Line Project

UniSource is working with officials from the Coronado National Forest concerning procedures and requirements for obtaining a special use authorization, including environmental reviews as required by the National Environmental Policy Act (NEPA).

The Forest Service hosted public scoping meetings in May 2024.

The Arizona Corporation Commission voted in June 2023 to approve the Certificate Environmental Compatibility issued by the Arizona Power Plant and Transmission Line Siting Committee.

• Rio Rico to Harshaw 138kV Transmission Line Project  - ACC Order Approving CEC

CEC Application Exhibits A-I

• Full-size PDF 173mb

Exhibit J

• Full-size PDF 139mb

• Prefiling Conference Transcript Feb. 23, 2023
• Notice of Hearing — signed March 6, 2023
• Prehearing Conference Transcript — April 13, 2023
• Line Siting Hearing, Day 1 Transcript — April 17, 2023
• Line Siting Hearing, Day 2 Transcript — April 18, 2023
• Line Siting Hearing, Day 3 Transcript — April 19, 2023

Virtual Project Tour

UniSource invited approximately 13,000 area residents and business owners to participate in an in-person open house meeting held on Jan. 25, 2023.

• Meeting Presentation
• Exhibits
• Visual Simulations

UniSource invited approximately 14,000 area residents and business owners to participate in an in-person open house meeting held on Nov. 17, 2022.

• Meeting Presentation
• Exhibits

UniSource invited approximately 14,000 area residents and business owners to participate in a hybrid virtual/in-person open house meeting held on Aug. 25, 2022

• Meeting Presentation

UniSource invited approximately 14,000 area residents and business owners to participate in a virtual open house meeting held on May 13, 2021.

• Meeting Presentation
• Q&A Transcripts

UniSource invited more than 11,000 area residents and business owners to participate in a virtual open house meeting held on September 24, 2020 from 6-8 p.m.

• Meeting Presentation PDF
• Q&A Transcripts

Components of the Rio Rico- Harshaw Line include:

• Proposed Rio Rico 138 kV Switchyard: A new switchyard is required to connect to UniSource’s existing 138 kV transmission system. The proposed switchyard would be located near Interstate 19 and the International Wastewater Treatment Plant in the Rio Rico area.
• Rio Rico-Harshaw 138 kV Line: A new line, approximately 20 miles long, to be constructed between the proposed Rio Rico 138 kV Switchyard and the proposed Harshaw Substation.
• Proposed Harshaw Substation: The new line will interconnect with a proposed 138/13.2 kV substation located on the privately- owned Hermosa Project site in Santa Cruz County, about 20 miles northeast of Nogales and about nine miles southeast of Patagonia, Arizona.

UniSource plans to build the line with self-weathering steel monopoles 75-110 feet tall. Taller structures may be required at major road or line crossings.

The Rio Rico to Harshaw Line will require 100-foot-wide rights-of-way to cross private and government-owned land in Santa Cruz County.

When determining where to locate new electric infrastructure, UniSource considers customers’ projected energy needs, proximity to and potential conflicts with existing infrastructure, project costs, environment and land use, input from the public and other factors.

UniSource developed a project study area based upon the anticipated future energy needs of the Hermosa Project, outage history, existing distribution infrastructure and utility corridors within the area, and the potential point of interconnection to UniSource’s existing 138 kV transmission system.

UniSource completed environmental studies and gathered public comment to evaluate potential transmission line routes within the study area. UniSource has also consulted with federal, state, and local jurisdictions and other interested parties regarding the Rio Rico-Harshaw Line.

When possible, UniSource will utilize existing utility and transportation corridors to help minimize any environmental and land use impacts of the line.

Public and agency input has been an important component of the planning process for the Rio Rico-Harshaw Line. UniSource requested public input through virtual presentations, newsletters, and other forms of communication.

A compilation of comments received on the project are available to view.

• Comments Updated Feb. 9, 2023

As the project continues through permitting, right-of-way acquisition, and construction, residents and other stakeholders are always welcome to share their input by contacting us at:

UniSource Energy Services
ATTN: Rio Rico-Harshaw
PO Box 711
Tucson, AZ 85702

• Sending an email to RR2Harshaw@uesaz.com
• Calling 1-833-783-0396 and leaving a voicemail message.

Click here to view a map of the area

As required by Arizona law, UniSource obtained a Certificate of Environmental Compatibility (CEC) from the Arizona Corporation Commission (ACC) before constructing the transmission line.

UniSource filed a CEC application in March 2023 with the Arizona Power Plant and Transmission Line Siting Committee (Line Siting Committee).  In April 2023, the Line Siting Committee voted unanimously to grant UNSE’s application for a Certificate of Environmental Compatibility (CEC) for the Rio Rico to Harshaw 138 kilovolt (kV) Transmission Line Project. The Arizona Corporation Commission reviewed and approved the CEC in June 2023.

UniSource has applied for a special use authorization from the U.S. Forest Service (USFS) to authorize a segment of the Rio Rico-Harshaw Line that is proposed to be built on lands within the Coronado National Forest (CNF).

The company is working with CNF officials concerning procedures and requirements for obtaining the special use authorization, including environmental reviews as required by the National Environmental Policy Act (NEPA).

The Rio Rico to Harshaw Line’s development timeline will depend in part on the length of the permitting processes.

Newsletters

• Newsletter #5, January 2023 — English | español
• Newsletter #4, October 2022 — English
• Newsletter #3, August 2022 — English | español
• Newsletter #2, April 2021 — English | español
• Newsletter #1, September 2020 — English | español