Siting Selection Process

Two people working on blueprints.


The siting selection process outlined below applies to overhead transmission lines of 115kV or greater, per the ACC requirements. However, APS may also elect to use this process for 69kV transmission lines.

Project Identification
Through internal studies, we identify the need for a new sub-transmission or transmission line to meet expected customer needs or help improve reliability of the energy grid and begin the siting process.

Hire Environmental Consultant for Siting Study
We will hire a consultant to assist in the process, conduct environmental studies and help direct public outreach.

Define Broad Study Area
In conjunction with the consultant, we will define a study area that includes all reasonable and feasible alternatives.

Identify Opportunities and Constraints
We will identify features within the identified study area that could serve as potential sites or routes for the new project. Features that can serve as opportunities include but are not limited to existing linear features, vacant land and designated utility corridors. Constraints may include but are not limited to dense residential development areas or designated scenic areas. If routes are identified that may require a crossing of federal land, studies consistent with a National Environmental Policy Act (NEPA) process may be required.

Conduct Communications and Outreach
As part of any siting process, we will address public and agency concerns, hold briefings with elected officials, send letters to interested parties and agencies, and give presentations to homeowner groups.

Identify Potential Transmission Line Links and Substation Sites
Following the identification of opportunities and constraints, we will identify reasonable paths and/or sites for the project route. These various segments, which may be referred to as “links,” can be connected to form different alternative routes to be evaluated during the next steps of the siting process.

Gather Public Comment
During the timeframe that we are identifying potential routing links, we will typically present the project to the public through a newsletter and possibly an open house. At the open house, we will present displays showing the project purpose and need, share design considerations and provide opportunities for public comment.

Screen Links and Substation Sites
We will evaluate the various routing links and/or sites identified earlier based on environmental considerations including biological resources, existing and potential land use, visual and scenic quality, and archaeological resources.

Refine Routes Between Termination Points
Following the evaluation of the routing links, the links will be refined to a reasonable set of alternative routes and/or sites for comparison and presentation to agencies and the public.

Gather Public Comment
We typically will present the alternative routes and/or sites to agencies and the public in a second newsletter and potentially a second open house. We will consider the public comment gathered through the public outreach efforts or the open house during the final route comparison.

Identify and Rank Routes and Substation Sites
The alternative routes and/or sites carried forward from earlier in the process will go through a final evaluation. This evaluation includes engineering feasibility, regulatory approvals, public comment, cost, land acquisition and environmental concerns.

Select Preferred Routing and Substation Sites
The final routing and/or site identification will be selected based on siting criteria.

Gather Public Comment
As a last step, we will present the final routing and/or site selection to the public through a final newsletter and possibly a final open house.
Copyright © 2024 APS.  All rights reserved.
Current server address is