Minnesota approves route for Big Stone South to Alexandria power line

The Minnesota Public Utilities Commission has approved a route permit for the Big Stone South to Alexandria 345-kilovolt transmission line, clearing a key hurdle for a project that will eventually run about 96 miles across western Minnesota. Otter Tail Power Company and the Western Minnesota Municipal Power Agency will co-own the line, which is expected to affect landowners in portions of Big Stone, Swift, Stevens, Pope and Douglas counties before it reaches the Alexandria Substation near Alexandria.

The written order, issued June 25, moves the project from the regulatory phase toward the right-of-way stage. Next, right-of-way agents will work with landowners along the approved route to establish easements and determine where structures will be placed. For property owners, that is the point when the project becomes tangible, with conversations about access, compensation and exact siting likely to begin well before construction crews arrive.

The line is the western segment of the larger Big Stone South-Alexandria-Big Oaks 345-kV transmission project. The full project received a certificate of need from the commission on Oct. 3, 2024, and the western segment’s route permit application was filed that same month. Project materials say the line is needed to add transmission capacity, reduce current capacity problems and improve electric system reliability across the region.

The route starts at Otter Tail Power’s Big Stone South Substation near Big Stone City, South Dakota, and ends at the Alexandria Substation owned by WMMPA. The project also includes a new fiber optic regeneration station, adding communications infrastructure alongside the electrical line itself. That combination matters for the long haul: the transmission line is meant to carry more power, while the fiber equipment supports system operations that help utilities manage the grid.

Otter Tail Power said the line is part of a broader effort to support future electric service needs, reduce congestion on the grid and improve access to renewable energy resources in the Upper Midwest. The company has described the project as a collaboration involving Otter Tail Power, Great River Energy, Minnesota Power, Missouri River Energy Services on behalf of WMMPA and Xcel Energy.

Construction is anticipated to begin in 2028, with the line targeted to be in service by the end of 2030. For Otter Tail County readers, the immediate change is not a new wire in the sky, but the start of land negotiations tied to a major regional infrastructure project that will shape reliability and power planning for years to come.