project description
engineering requirements:
- New single-circuit 500kV transmission line 350- 390 miles to existing Borah or Midpoint Substation, southeast Idaho
- New substation south of Townsend, Montana
- Right-of-Way Width: 220 feet
- Lattice Steel or Tubular Steel Transmission Towers
- Tower Height: 110-130 feet
- Average Span Length Between Towers: 1,500 feet
- Estimated Construction Period: 2010 to 2013
- Expected In-Service Date: 2013
The project will run from a new substation south of Townsend, MT to the Mill Creek Substation and then south to the Midpoint Substation in southern Idaho.
Garrison, Ringling, and Townsend were all considered for the northern terminus and tie into the existing Colstrip 500 kV transmission lines. Both Midpoint and Borah were considered for the southern interconnection point.