Proving Ground Solar and Storage 500kV Interconnect

Father holding toddler outside


Voltage: 500kV
Estimated Siting completion date: 1st quarter 2023
Location: North of Dateland, AZ

Project need
A new 500 kilovolt (500kV) transmission line is required to interconnect a portion of the Proving Ground Solar and Storage Project north of Dateland, from a new step-up substation to the Hoodoo Wash Substation.

Project description
We have partnered with Strata Clean Energy, LLC (Strata) in developing a renewable energy facility in Yuma County, Arizona – the Proving Ground Solar and Storage 500kV Interconnect Project. The project involves a 250-megawatt (250MW) solar photovoltaic generating facility with battery storage, an approximately 6-mile-long double circuit 69-kilovolt (69kV) generation intertie transmission line (gen-tie), a step-up substation, and a 500-kilovolt (500kV) interconnection transmission line (interconnection line) from the step-up substation to the Hoodoo Wash Switchyard. The interconnection line will be an approximately 3,000-foot-long, 500kV transmission line. The solar + storage facility will be located on approximately 2,050 acres of privately owned land, the gen-tie will be located on right-of-way (ROW) from the Arizona State Land Department and Bureau of Land Management (BLM), and the step-up substation and interconnection line will be on ROW from the BLM and across privately owned land. The project and interconnection facilities will be located north of Palomas Road, approximately 10 miles north of Dateland, in unincorporated Yuma County.

Project Map 1
Project Map 2

Project Planning
In 2018, the Yuma County Board of Supervisors approved a special use permit to allow construction and operation of the project in conformance with the Yuma County Zoning Ordinance. A portion of the gen-tie, the step-up substation, and a portion of the interconnection line will be located on rights-of-way obtained from the Arizona State Land Department, across Arizona State Trust land, and from the Bureau of Land Management (BLM). We are currently working with the BLM to amend its existing right-of-way grant to match the final design of the 500kV interconnection line, step-up substation, and associated improvements on BLM-managed lands. Updates and new information will be made available on this website.

A Certificate of Environmental Compatibility (CEC) from the Arizona Corporation Commission and Arizona Power Plant and Transmission Line Siting Committee is required to allow for construction and operation of the 500kV interconnection line. We expect that a portion of the new line will be co-located on structures with the existing 500kV Hassayampa-North Gila #2 transmission line (HANG#2). Co-locating the lines would help consolidate energy infrastructure and minimize the overall impact of the project (see Project Map 2). Although we will be the applicant for the CEC, Strata is continuing the permitting of the project on our behalf.

As part of the public outreach process for the project, Strata held an open house meeting at the Dateland Elementary School in December 2021 to present information about the project, answer questions, and receive comments.

Project features
We are coordinating the design of the interconnection line with Strata and have carefully considered the potential visual impacts in siting the proposed step-up substation and interconnection line. The 500kV portion of the new line would be co-located on existing 500kV structures. Co-locating this portion of the interconnection line will help consolidate energy infrastructure and minimize visual impacts overall. The visual simulations showing existing and proposed conditions from two perspectives on Palomas Road are depicted below.

Simulation #1
Simulation #2

We anticipate that the CEC process will be complete in early 2023, subject to the availability of the Arizona Power Plant and Line Siting Committee. Construction for the project is estimated to begin in Spring 2023.

Project updates
On Jan. 5, 2023, we filed an application for a Certificate of Environmental Compatibility (CEC) with the Arizona Corporation Commission (ACC); the Interconnection Project is docketed as L00000D-23-0011-00214. This project will be presented at a hearing before the Arizona Power Plant and Line Siting Committee (Siting Committee). If approved by the Siting Committee, the CEC will then be presented to the ACC for their consideration and final decision.

Public Hearing Information
Please join our project team and the Siting Committee for a public hearing on the Runway 230kV Power Line project. This hearing will be held regarding our application for a CEC authorizing construction of the project.

Date: Feb. 13, 2023, beginning at 1:00 p.m. Public comments will be taken beginning at 5:30 p.m. on this day.

Location: Yuma Four Points by Sheraton - 2030 S. Avenue 3E, Yuma, AZ 85365.

Please note, the hearing will continue through Feb. 15, 2023, starting at 9:00 a.m. each day as necessary through the completion of the hearing.

Information regarding online and telephone hearing access will be available at least 24 hours in advance of the hearing, as well as any additional details regarding public health protocols, and any revisions to the hearing schedule.

The Committee will hear public comment on February 13, 2023, beginning at 5:30 PM; public comment may be delivered in-person at the Yuma Four Points by Sheraton, virtually, or via telephone. The Committee Chairman may, at his discretion, allow additional public comment at other times during the hearing.

The CEC Application, and additional documents and links related to the public hearing, are available below. Zoom links and telephone dial-in information will be posted in this section.

Public input
We welcome feedback for this project. Comments or questions can be submitted the following ways:

Related documents
Newsletter #1
Newsletter #2
Project Overview Boards
Prefiling Exhibits
Prefiling Transcripts
CEC-214 Application
Notice of Hearing
Hearing Agenda
Procedural Order
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