Montana-Dakota Utilities Co., a division of MDU Resources Group, Inc. (NYSE:MDU), announced today that it has signed a power purchase agreement with Thunder Spirit Wind LLC, a subsidiary of Wind Works Power Corp. The agreement is for approximately 105 megawatts of installed capacity of wind turbine generators to be located in southwest North Dakota near Hettinger. The generation will interconnect at Montana-Dakota’s substation near Hettinger. The project is expected to begin commercial operation in the fourth quarter of 2015. Montana-Dakota issued a request for proposal earlier this year for electric capacity and energy. The Thunder Spirit Wind proposal will provide Montana-Dakota customers with stable pricing over the 25-year contract. “This is a competitively priced agreement that will serve our customers for many years to come,” said K. Frank Morehouse, president and CEO of Montana-Dakota Utilities. “Moving some of our current market energy purchases into a fixed contract helps protect our customers from unexpected changes in market pricing.” In addition to renewable generation owned by Montana-Dakota, the agreement with Thunder Spirit Wind means 20 percent of Montana-Dakota’s energy supply requirements will come from renewable resources. Montana-Dakota Utilities Co. distributes natural gas and generates, transmits and distributes electricity and provides related services in the northern Great Plains. The company serves approximately 135,000 electric customers and 245,000 natural gas customers in 262 communities in North Dakota, South Dakota, Montana and Wyoming. Montana-Dakota is a division of MDU Resources Group, Inc., a diversified natural resources company traded on the New York Stock Exchange as “MDU.” For more information about MDU Resources, visit the company’s Web site at www.mdu.com . For more information about Montana-Dakota, visit www.montana-dakota.com .