Project overview

This project will consist of rebuilding and reconductoring existing high voltage transmission line infrastructure from Idaho to Utah. The project involves the following substations: Populus, Bridgerland, Ben Lomond, Threemile Knoll, Soda, Grace, Oneida, and Treasureton. The project will be completed in two phases.  The first phase will focus on the 67-mile, 345 kV reconductor that anticipates completion by the end of 2028. The second part of the project will focus on the 40-mile, 138 kV rebuild that anticipates completion by the end of 2030. This project will increase overall system reliability while improving capacity.

About the project

The purpose and need for the Populus to Terminal Segment B project rebuild is to ensure the transmission system is reliable. Due to increased electrical demand, the existing transmission infrastructure will not have sufficient capacity to reliably serve future load requirements. This reconductoring and rebuild will provide additional capacity to help in serving load growth while increasing overall system reliability. 

The project will feature the following components:

• Approximately 67 miles of reconductor of the Ben Lomond-Populus East 345 kV line between the Populus substation in Downey, Idaho, and the Honeyville Crossover in Honeyville, Utah.
• Approximately 25 miles of rebuild of double-circuit 138 kV from Grace Substation in Grace, Idaho, to Treasureton Substation in Treasureton, Idaho.
• Approximately 15 miles of rebuild on the single-circuit 138 kV from Grace Substation in Grace, Idaho, to near the Threemile Knoll Substation in Soda Springs, Idaho. 

Project map

The affected entities in this project include the Bureau of Land Management, the Bureau of Reclamation, as well as local jurisdictions that include:

The link to the project map indicates the route and the two phases through which work will be completed.

Segment B Honeyville to Populus and Threemile Knoll - Project Map

Project timeline

After providing a project introduction to local jurisdictions, PacifiCorp will provide opportunities to inform the public of the project and will answer questions. Throughout the permitting process, it is anticipated that local jurisdictions along the project route may require additional public outreach and engagement.  Information about all open house meetings and engagement opportunities will be noticed and can also be found on this page. 

Public outreach

More information will be made available soon.

More information

Requests for additional information on the Populus to Terminal Segment B project may be directed to pmopac@PacifiCorp.com. Please include the word “Segment B” in the subject line and provide your contact information and preferred contact method in the body of the message.