USA, North Dakota / South Dakota: Otter Tail Power Co. and Xcel Energy are planning a new 240-km (150-mi) transmission line linking the Fargo area with north-eastern South Dakota, in a project intended to strengthen regional grid reliability.
The proposed Big Stone South–Hankinson–Bison transmission line would run from the Bison Substation, around 24 km (15 mi) north-west of Fargo and eight kilometres (five miles) north of Mapleton, North Dakota, to the Hankinson Substation and then to the Big Stone South Substation, located about 97 km (60 mi) north-east of Watertown, South Dakota.
The 345 kV line is expected to use single-circuit, self-supporting monopoles between 36 and 48 m (120 and 160 ft) tall, with spans of around 213 to 365 m (700 to 1,200 feet). The planned right-of-way is approximately 45 m (150 ft) wide.
The companies are currently reviewing route options and working through the permitting process. Construction could begin in mid-2030, with the line expected to enter operation in late 2033. The route under study runs west of Fargo and along Interstate 29, crossing Cass and Richland counties in North Dakota and Grant and Roberts counties in South Dakota.
The project will require approvals from the North Dakota Public Service Commission and the South Dakota Public Utilities Commission, as well as local building permits.
According to Otter Tail, the line is one of five high-priority projects in the Joint Targeted Interconnection Queue and is designed to improve interconnection between the Southwest Power Pool and Midcontinent Independent System Operator regions. The companies say it will help relieve pressure on overloaded transmission lines and improve system resilience during emergencies and periods of high demand.
Source: INFORUM
