The 250-mile CapX2020 Brookings County-Hampton 345 kV transmission line was energized March 26, 2015. The project will help meet projected electric growth in southern and western Minnesota, and the growing areas south of the Twin Cities metro area, particularly Scott and Dakota counties. The project also connects to new renewable generation resources in southern and western Minnesota, and the Dakotas.
A Certificate of Need for the project was granted by the Minnesota Public Utilities Commission (MN PUC) in 2009. A Route Permit for the majority of the project was issued by the MN PUC in fall 2010, with a final portion approved in early 2011 (MN PUC docket 08-1474). The Route Permit was granted after a multi-year route development and regulatory review process. The South Dakota Public Utilities Commission (SD PUC) issued a facility permit for the project in 2011.
Between the Lyon County Substation and Helena Substation, the project was built as a double-circuit transmission line; remaining segments were built as double circuit capable, though only a single circuit was energized after construction. If or when the second circuit is required, a new regulatory proceeding will be initiated.
Single pole structures were used to reduce land impacts. Structures are generally between 140 and 170 feet tall and are spaced between 800 and 1,000 feet apart. Typically, a 150-foot right-of-way was acquired.
Construction schedule history
The Brookings County-Hampton project was energized March 26, 2015.
Crews will continue restoration efforts along the transmission line. In addition, crews will finish installing interphase spacers this year, with work on the segment between the Cedar Mountain Substation and the Helena Substation scheduled to take place June through August. Installation on the segment between the Lyon County Substation and the Cedar Mountain Substation will take place in August and September. Interphase spacers are devices that help prevent “galloping”, or movement of the conductors during certain weather conditions. Galloping can stress or damage components of the line and cause outages.
Cedar Mountain Substation (Renville County) to Helena Substation (Scott County): Construction of the 72-mile segment began in April 2012 and was completed in September 2013. A 4-mile 115 kV connection with the Franklin Substation was built as part of this segment. It was placed in service March 2014.
Cedar Mountain Substation to Lyon County Substation (east of Marshall): Construction of the 50-mile segment began in spring 2013 and was completed in late 2013. The line was placed in service March 2014.
Helena Substation to Chub Lake Substation (Scott County east of I-35): Construction of the 20-mile segment began in July 2013 and was completed in spring 2014. The line was placed in service April 2014.
Chub Lake Substation to Hampton Substation (Dakota County): Construction of the 18-mile segment began in autumn 2013 and was completed in April 2014. The line was placed in service April 2014. Restoration was completed in late June 2014.
Lyon County Substation to Brookings County Substation (northeast of Brookings, South Dakota): Construction of the 58-mile segment began in late 2013 and was energized Feb. 25, 2015.
Construction of the Cedar Mountain Substation was completed and placed in service March 31, 2014.
Expansion of the Chub Lake/Lake Marion Substation was placed in service in April 2014. The final site construction was completed June 1, 2014.
Lyon County Substation to the Hazel Creek and Minnesota Valley Substations (near Granite Falls in Yellow Medicine County): Construction of the 30-mile segments began in early 2014. The line was placed in service March, 2015.
The MN PUC must grant two approvals before construction – a Certificate of Need and a Route Permit. An environmental report was prepared by the Department of Commerce, Office of Energy Security during the need process, and an Environmental Impact Statement was written during routing.
A map of the route in the area can be found here.
South Dakota permitting
The South Dakota Public Utilities Commission must issue a Facility Permit before transmission line construction.