The project was initiated and completed to support continued reliable, safe and cost-effective electricity to customers, provide needed customer transmission service, and support new renewable energy development. Construction of the line was initiated in 2018 for the new transmission line between our Wallula Substation in Washington and Bonneville Power Administration’s McNary Substation near Umatilla, Oregon. The transmission line was originally planned to also connect Wallula with an existing substation in Walla Walla Washington. That section, however, is not scheduled to proceed at this time. The 30-mile, 230 kilovolt line between Wallula and McNary was constructed on a 125-foot wide right-of-way. We worked to minimize impacts to the community and local environment during project development, construction and maintenance. The project was placed in service January 31, 2019.
The proposed Boardman to Hemingway transmission line is a 500-kilovolt line that would run approximately 300 miles from a new substation proposed near Boardman, Oregon, to the Hemingway substation near Melba, Idaho, southwest of Boise, Idaho.
Building a line west from Idaho will increase system flexibility and reliability to serve customers. While originally proposed as an approximately 375-mile, single-circuit 500 kilovolt transmission line from the Hemingway substation to a substation near Klamath Falls, Oregon, we pursued joint development opportunities with regional entities on alternatives to this proposed configuration. To that end, in January 2012, we signed a permit funding agreement with Idaho Power and Bonneville Power Administration on the proposed Boardman to Hemingway line.
Transmission options for “Boardman to Hemingway” are being considered from among alternative projects and will be brought into service as soon as appropriate for PacifiCorp customers.
Note: The current project schedule includes a construction start date in July of 2023 with completion mid-year 2026.
(Updated April 2023)