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Studies and Reports > 2009 MN Biennial Report > SE Planning Zone > Needs: 6.7.12 Mankato-Decoria-Minnesota Lake Area

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Transmission Projects Report 2009
Section 6.7: Southeast Zone
p. 278

6.7.12 Mankato-Decoria-Minnesota Lake Area

Tracking Number. 2009-SE-N2

Utility. Great River Energy

Inadequacy: This area consists of a 69 kV line from Stoney Creek to Minnesota Lake and Danville. The normal source for this is the Stoney Creek 115/69 kV substation. During outages of this source, line switching allows the loads to be served from the 69 kV source at Albert Lea. The Stoney Creek source is under development and is expected to be in service in 2010. See Tracking No. 2003-SE-N3. Based on load projects for the area referencing GRE’s 2008 Long Range Plan, deficiencies will occur in the 2015 time frame during contingency loss of the 69 kV source at Stoney Creek. The back-up source is located a relatively long distance away at Albert Lea and the voltages at Decoria and St. Clair can no longer be adequately supported.

A map of the Decoria-Minnesota Lake Area is on the following page.

Alternatives: The long term solution proposed is a new 69 kV line (built at 115 kV) between the Loon Lake substation near Waseca and the St. Clair substation southeast of Mankato. The project consists of the following components:

  • 25 miles of 69 kV line, 477 ACSR, built to 115 kV standards, initially operated at 69 kV
  • 69 kV breaker addition at the Loon Lake substation
  • 3-way, motor operated switch at the St. Clair substation

Analysis: Additional analysis will be done prior to initiating the solution proposed above to determine whether it is still the appropriate solution to the long-term needs of the area south of Mankato. The total estimated cost for this project is approximately $10,000,000.

Schedule: This project is needed by the summer of 2016. A Certificate of Need from the Public Utilities Commission will be required for the 25 mile 115 kV line and a Route Permit from the PUC or local government will also be required.


Transmission Projects Report 2009
Section 6.7: Southeast Zone
p. 279

Click here or on map below to download high resolution PDF map.