In a deal said to be the largest ever involving electric cooperatives, a group of 12 cooperatives completed the purchase of Alliant Energy’s electric service territory in southern Minnesota, which serves more than 43,000 customers.

The agreement was signed in September 2013 between Interstate Power and Light Co. (IPL)—Alliant’s Iowa utility—and Southern Minnesota Energy Cooperative (SMEC), which was formed as the single point of contact for the purchase of the territory.

The 12 member cooperatives included in SMEC are BENCO Electric Cooperative, Brown County Rural Electrical Association, Federated Rural Electric, Freeborn-Mower Cooperative Services, Minnesota Valley Electric Cooperative, Nobles Cooperative Electric, People’s Energy Cooperative, Redwood Electric Cooperative, Sioux Valley Energy, South Central Electric Association, Steele-Waseca Cooperative Electric, and Tri-County Electric Cooperative.

The deal included a wholesale power supply agreement between IPL and SMEC with a five-year termination notice requirement, which may not be given until the fifth anniversary of the effective date, resulting in a minimum term of 10 years. The agreement remains in effect indefinitely, unless notice to terminate is provided by either party.

Earlier this year Alliant sold its Minnesota natural gas system to Minnesota Energy Resources. The Madison, Wis.–based company said its strategic plan focuses on the core business of delivering regulated electric and natural gas service in Iowa and Wisconsin.

Aaron Larson, associate editor (@AaronL_Power, @POWERmagazine)