Energy Gateway

PacifiCorp's Energy Gateway Transmission Expansion Program represents plans to build over 2,300 miles of new high-voltage transmission lines, with an estimated cost of over $8 billion, primarily in Wyoming, Utah, Idaho and Oregon. The over $8 billion estimated cost includes:

  • The 135-mile, 345-kV transmission line between the Terminal substation near the Salt Lake City Airport and the Populus substation in Downey, Idaho, placed in-service in 2010;
  • The 100-mile, 345/500-kV transmission line between the Mona substation in central Utah and the Oquirrh substation in the Salt Lake Valley, placed in-service in 2013;
  • The 170-mile, 345-kV transmission line between the Sigurd substation in central Utah and the Red Butte substation in southwest Utah, placed in-service in 2015;
  • The 140-mile, 500-kV transmission line between Aeolus substation near Medicine Bow in Wyoming and Jim Bridger generating facility, placed in-service in 2020;
  • The 416-mile, 500-kV high-voltage transmission line between the Aeolus substation and the Clover substation near Mona, Utah, expected to be placed in-service in 2024;
  • The 59-mile, 230-kV high-voltage transmission line between the Windstar substation near Glenrock, Wyoming and the Aeolus substation, expected to be placed in-service in 2024;
  • The 290-mile, 500-kV high-voltage transmission line from the Longhorn substation near Boardman, Oregon to the Hemingway substation near Boise, Idaho (a joint project with Idaho Power and the Bonneville Power Administration), expected to be placed in-service in 2026; and
  • Other segments that are expected to be placed in-service in future years, depending on load growth, economic analysis, IRP results, siting, permitting and construction schedules.

Energy Gateway transmission expansion

The new Energy Gateway transmission line segments are intended to: (a) address customer load growth; (b) improve system reliability; (c) reduce transmission system constraints; (d) provide access to diverse generation resources, including renewable and zero carbon resources; and (e) improve the flow of electricity throughout PacifiCorp's six-state service area. Proposed transmission line segments are evaluated to ensure optimal benefits and timing before committing to move forward with permitting and construction. Through December 31, 2021, $2.9 billion had been spent and $2.4 billion, including AFUDC, had been placed in-service.

The map shows the individual segment additions that comprise the Energy Gateway expansion. Depending on regional, third-party, and local participation, the final lines may vary somewhat. PacifiCorp is taking every reasonable step to accommodate regional transmission needs and we are committed to building Energy Gateway with our primary responsibility to provide customers with safe, reliable, and reasonably priced electrical service.

Links to Energy Gateway segment information can be found below. We update these pages as new information becomes available.

(Updated September 2023)

Gateway Central

Segment B – Populus to Terminal

Segment C – Mona to Oquirrh

Segment C – Limber to Terminal

Gateway West

Segment D.1 – Windstar to Aeolus (future segment)

Segment D.2 – Aeolus to Bridger/Anticline

Segment D.3 – Bridger/Anticline to Populus (future segment)

Segment E – Populus to Hemingway (future segment)

Gateway South

Segment F – Aeolus to Mona/Clover

Segment G – Sigurd to Red Butte

West of Hemingway

Segment A – Wallula to McNary

Segment H – West of Hemingway