Bonneville Power Administration States Preference for Other Transmission Options over Mountain States Transmission Intertie to Serve Southern Idaho Energy Load

SIOUX FALLS, S.D., Oct. 3, 2012 /PRNewswire/ -- NorthWestern Corporation d/b/a NorthWestern Energy (NYSE:NWE) today announced that the Bonneville Power Administration (BPA) notified the company that it has ranked other options ahead of the Mountain States Transmission Intertie (MSTI) to serve BPA's southern Idaho loads. This notification was in conjunction with the January 2012 Memorandum of Understanding between NorthWestern and BPA agreeing to explore the potential for MSTI to accommodate BPA's need to serve its load obligations in southeast Idaho.

NorthWestern previously disclosed that it would consider writing down or writing off the costs of the MSTI project depending on the likelihood of reaching an agreement with BPA to serve its southern Idaho loads. Based on BPA's notification, continued market uncertainty and permitting issues, NorthWestern may write- off all, or a significant portion of preliminary survey and investigative costs totaling approximately $24 million associated with the MSTI transmission project. NorthWestern is currently evaluating if an impairment charge should be recognized. If NorthWestern concludes that a material impairment loss is required to be recognized, it will disclose the matter under Item 2.06 of Form 8-K.

While NorthWestern does not anticipate incurring significant additional costs in the foreseeable future related to MSTI, the company will continue to monitor market conditions and evaluate strategic options related to the MSTI project.

About NorthWestern Energy

NorthWestern Energy provides electricity and natural gas in the Upper Midwest and Northwest, serving approximately 668,300 customers in Montana, South Dakota and Nebraska. More information on NorthWestern Energy is available on the Company's Web site at

SOURCE NorthWestern Corporation