NorthWestern Energy (NWE) proposes to construct, operate and maintain the Mountain States Transmission Intertie (MSTI) 500 kilovolt (kV) transmission line to address the requests for transmission service from customers and to relieve constraints on the high-voltage transmission system in the region. The new transmission line would begin at the new Townsend Substation, which would be constructed in southwestern Montana about five miles south of the town of Townsend. The line would proceed south into southeastern Idaho connecting to Idaho Power Company’s (IPCO) existing Midpoint Substation, 10 miles north of Jerome, Idaho (Figure 1).
The major project components of the proposed action include the 500kV transmission line, new Townsend Substation, and modifications to the existing Midpoint Substation.
