Wood River-Ketchum Transmission Line

About the Project

The Wood River Valley Reliability Project is a combination of electric distribution, transmission, and substation work. Idaho Power will bury more than nine miles of existing distribution lines and build approximately 11 miles of new overhead and underground transmission line between the Wood River Substation in Hailey and the Ketchum Substation in northeastern Ketchum. The Blaine County Commission approved a plan to bury certain sections of the project. The Idaho Public Utilities Commission authorized a surcharge on Blaine County customers’ electric bills to pay for undergrounding those sections.

This project is under construction. For project updates and construction details, visit Wood River Valley Reliability Project.

Project Benefits

The new transmission line will make power more reliable in the Ketchum–Sun Valley area.

Today, the upper Wood River Valley is served by a single source: a 60-year-old transmission line. While it has reliably served the community for decades, having only one line means that if severe weather or another event interrupts service, the area could be without power for an extended time.

This project is designed to improve service and reliability for the Wood River Valley community:

More reliable power
A second transmission line allows electricity to be rerouted, reducing both the frequency and duration of outages.
Faster recovery from outages
Completing the system “loop” helps keep power on—even if one line is affected by weather or other events.
Stronger system in a challenging environment
The upgraded infrastructure is designed to better withstand the valley’s steep terrain and severe weather conditions.
Modern, updated infrastructure
Replacing aging equipment helps ensure safe, dependable service for years to come.

Purpose and Need

The need for this project has been identified over many years of planning and community input.

In 2007, Idaho Power partnered with the Wood River Community Advisory Committee, a group of local leaders, government officials, business representatives, and residents, to develop the Wood River Electrical Plan. The plan was refined in 2008 and updated again in 2011.

Through this process, the committee evaluated electric service across the Wood River Valley and identified a key need: adding a second 138-kilovolt transmission line between Hailey and the Ketchum–Sun Valley area to improve reliability.

In 2014, Idaho Power reconvened the committee to take another look at options for strengthening the system. After reviewing alternatives, the Wood River to Ketchum transmission line again emerged as the preferred solution.

Following this extensive planning and community input, the project moved into the regulatory process. In 2017, the Idaho Public Utilities Commission approved the project, recognizing the need to strengthen reliability in the valley. Blaine County approved a permit in 2021, and in 2023, the Idaho Supreme Court upheld that approval.

Project Timeline

Construction began in 2023, including work to place some existing lines underground. The project is expected to be complete in late 2026, depending on coordination with ongoing Highway 75 improvements.

For regular project updates and construction details, visit WOOD RIVER VALLEY RELIABILITY PROJECT