November 13, 2008

NorthWestern Energy Provides Update on Montana Public Service Commission Proceedings Regarding Colstrip Unit 4

BUTTE, Mont., Nov. 13 /PRNewswire-FirstCall/ -- NorthWestern Corporation d/b/a NorthWestern Energy announced today that the Montana Public Service Commission has made formal its approval of placing the company's ownership interest in Colstrip Unit 4 into the ratebase.

Effective January 1, 2009, 222 megawatts of electricity from the coal-fired unit in southeastern Montana will be placed into rates at value of $407 million. The decision makes Colstrip Unit 4 the foundation of NorthWestern Energy's efforts to become a vertically integrated utility in Montana.

"Our portion of Colstrip 4 will provide our Montana customers with a dedicated and stable source of electric supply. We appreciate the MPSC's thoughtful and expeditious consideration of our application," said Bob Rowe, president and CEO.

   The Commissioners voted 4-1 to approve the application.    About NorthWestern Energy  

NorthWestern Energy is one of the largest providers of electricity and natural gas in the Upper Midwest and Northwest, serving approximately 650,000 customers in Montana, South Dakota and Nebraska. For more information about NorthWestern Energy, visit our Web site at .

NorthWestern Corporation

CONTACT: Media, Claudia Rapkoch, 1-866-622-8081,[email protected], or Investor Relations, Dan Rausch,+1-605-978-2902, [email protected], both of NorthWestern Energy

Web site: