Gateway West

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Windstar to Populus (Gateway West - Segment D)

Gateway West segment D stretches approximately 488 miles starting at the Windstar Substation near Glenrock, Wyoming, proceeding south to Medicine Bow, Wyoming, and then spanning across southern Wyoming to the Populus Substation near Downey, Idaho. This segment is sub-divided into three elements and when fully completed this segment will enable access to existing and new generating resources, including wind, delivering electricity from these sources to customers.

The Windstar-to-Populus transmission project consists of three key sub-segments: 

• D1 (Windstar to Aeolus) — A single-circuit 230-kilovolt (kV) line running approximately 59 miles between the existing Windstar and Aeolus substations in eastern Wyoming, the project was completed in November 2024;
• D2 (Aeolus to Bridger/Anticline) — A single-circuit 500-kV line completed October 2020 and energized November 2020; and
• D3 (Bridger/Anticline to Populus) —A single-circuit 500-kV line running approximately 200 miles between the new Anticline Substation and the Populus Substation in southeast Idaho. The line is scheduled in service 2034 at the earliest.

The Energy Gateway West Subsegment D.1 project consists of a new 230 kV line and a rebuild of an existing 230 kV line between the Shirley Basin Substation in southeastern Wyoming to the Windstar Substation near Glenrock, Wyoming. The project was completed in November 2024.

Populus to Hemingway (Gateway West - Segment E)

The Populus-to-Hemingway transmission project consists of two single-circuit 500-kV lines that run approximately 500 miles between the Populus Substation in eastern Idaho to the Hemingway Substation in western Idaho.

The Gateway West Segment E project would enable PacifiCorp to more efficiently dispatch system resources, improve performance of the transmission system (i.e., reduce line losses), improve reliability, and enable access to a diverse range of new resource alternatives over the long term.

The overall project is estimated for completion in 2036 at the earliest, with some portion of the line may be energized earlier.

More details on Segment E progress: 

• Segment E8 – Midpoint to Hemingway: Part of Gateway West, Segment E includes building a new 128-mile 500 kV transmission line between the Midpoint Substation in Jerome, Idaho, and the Hemingway Substation in Melba, Idaho. 

(Updated January 2025)