Facility permit approved for new transmission line

Big Stone South to Alexandria transmission line will help ensure continued low-cost, reliable electricity

SIOUX FALLS, S.D. — On Jan. 28, the South Dakota Public Utilities Commission approved a Facility Permit for the South Dakota portion of the Big Stone South to Alexandria (BSSA) 345-kilovolt transmission line. Otter Tail Power Company and Western Minnesota Municipal Power Agency (WMMPA), represented through its agent Missouri River Energy Services (MRES), will co-own the approximately 100-mile transmission line.

The companies filed the Facility Permit application for the 3.5-mile South Dakota portion of the line on April 15, 2024.

Investing in grid reliability and resilience

Otter Tail Power is leading the BSSA transmission line development and construction.

“We’re pleased to reach this significant milestone. The Commission’s approval of this essential project highlights our commitment to maintaining a robust and reliable regional energy grid,” stated the utilities. “This transmission line represents an important infrastructure improvement and demonstrates our dedication to meeting the growing energy needs of our customers in a cost-effective manner.”

BSSA is designed to ensure continued electric reliability, enhance resilience to extreme weather events, reduce transmission congestion and increase access to low-cost energy.  It will connect Otter Tail Power’s existing substation near Big Stone City, South Dakota, with WMMPA's existing substation near Alexandria, Minnesota.

Otter Tail Power and MRES filed a Route Permit application with the Minnesota Public Utilities Commission (MPUC) on Oct. 22, 2024, for the Minnesota portion of the project. The companies anticipate a decision from the MPUC in mid-2026 and are currently targeting an in-service date for the project by the end of 2030.

For more information about BSSA, visit bigstonesouthtoalexandria.com.