Work in Progress

Transmission Line Rebuild and Second Point of Interconnect

Project Information

HL&P is moving forward with Rocky Mountain Power (RMP) to rebuild the transmission line from the Jordanelle Substation to the Midway Substation and adding a second electrical interconnection to the Western Transmission Grid. Summit Line Construction is performing much of the work to rebuild the line, and several segments are already complete.

The Transmission Route Map provides the estimated construction period for each section of the line. All sections will be double circuit, except for the Midway segment will be a single circuit. Crews will always notify customers affected by work that is scheduled in their area. Customers can expect to see old power poles replaced with new wood poles. Steel structures will also be placed along the route where they are required.

The cost of building the line has increased due to the increasing costs of construction materials. HL&P estimates that the remaining sections of the transmission line will cost around $2M a mile, including the right of way costs. The cost split between RMP and HL&P is 80/20. RMP will own and maintain the poles and three conductors on one side of the poles and HL&P will own three conductors on the other side of the poles. Sharing facilities saves HL&P millions of dollars and minimizes the number of poles needed for the joint project.

This project provides a much-needed increase to HL&P’s electrical service capacity, resiliency, and reliability. We appreciate your understanding as crews work to shore up our electrical system so that we can provide reliable service for many years to come.

Work-In-Progress Timeline

  • March 29, 2021- April 12th: Crews will begin working on sections 140A, 140B, and 140C in the south field area.
  • April 12th through May 3rd: Sections 140D, 900A, 900C along 650 South will be rebuilt. 
  • May 1st- July 1st: The northern section 110C will be rebuilt.
  • June 1st- August 31st: Sections 150A, 150B, and 150C from the sewer ponds to the fish hatchery will be rebuilt.
  • August 1st – September 30th:  Section 170 to the Midway Substation will be rebuilt.
*Work dates, locations, and details will be updated as the project progresses. 

Transmission Route Map with Section Detail

Zoom in and click on a line section to see the section name and estimated work dates. 
Click on the arrow in the upper left corner of the map to see the legend.
All segments will be double circuit construction, except the Midway segment will be single circuit.