Montana-Dakota Utilities Co. has signed a 25-year purchase agreement for power from the expansion of Thunder Spirit Wind near Hettinger.
The company purchased the original 43-turbine, 107.5-megawatt wind farm from Allete Clean Energy for $200 million in December.
The agreement also includes an option for MDU to buy the project at the close of construction. The expansion includes 13 to 16 turbines, adding about 40 megawatts to the wind farm and bringing total production to about 150 megawatts.
Construction costs for the project are estimated at $85 million, and it is expected to be online by December 2018.
“Our relationship with ACE on the first phase of Thunder Spirit Wind proved to be a winning formula. We are in need of additional energy to meet our growing demands, and, with the easements, interconnection to the grid and permits already in place from the first phase of Thunder Spirit Wind, it makes this a great project for Montana-Dakota,” MDU Chief Executive Officer Nicole Kivisto said in a statement.