20260420News Release.pdf

Idaho Public Utilities Commission Brad Littte,Governor
P.O. Box 83720. Boise, ID 83720-0074 Edward Lodge, President
John R.Hammond, Jr.,Commissioner
Dayn Hardie,Commissioner
Case No. IPC-E-26-09
Case No. PAC-E-26-06
Order No. 37010
Contact:Adam Rush
Office: [phone]
E-mail Address: [e-mail]
NEWS RELEASE: Electric utilities file applications seeking certificates of public convenience
and necessity to begin construction of transmission line segment.
BOISE (April 20, 2026)—Rocky Mountain Power and Idaho Power have filed applications with
the Idaho Public Utilities Commission seeking certificates of public convenience and necessity
that would allow the utilities to begin construction of a proposed transmission line segment that
is designed to provide an additional 2,000 megawatts in transmission capacity.
Segment E-8 of the Gateway West project is a 500-kilovolt line that will start at the Midpoint
Substation near Jerome, Idaho, and run to the Hemingway Substation near Melba, Idaho.
Segment E-8 also will connect to Idaho Power's proposed 500-kilovolt Mayfield Substation.
The utilities stated that Segment E-8 will add transmission capacity and deliver energy to the
Treasure Valley from Mountain Home and the Magic Valley in the Twin Falls area. Construction
on Segment E-8 is scheduled to begin in October of 2027 and will be completed in three phases.
Phase I and II will connect the Hemingway Substation to the Mayfield Substation while phase III
will extend the Mayfield Substation to the Midpoint Substation. Phase III is expected to begin in
2030.
Idaho Power will hold 99 percent ownership in the segment and Rocky Mountain Power's parent
company, PacifiCorp, will hold the remaining 1 percent.
Additional information is available at: puc.idaho.gov/case/Details/7741 and
puc.idaho.gov/case/Details/7740.