BILLINGS, Mont. (AP) — NorthWestern Energy's proposal to purchase a larger portion of a coal-fired power plant in southeastern Montana for $1 doesn't include analysis to show the acquisition is in the public interest and will result in reasonable electricity charges, a legal team representing customers of Montana's utilities said.

Consumer Counsel Bob Nelson said the Public Service Commission should pause its consideration of NorthWestern's proposed purchase of 25% of Colstrip's Unit 4 from Puget Sound Energy until NorthWestern provides more information.

NorthWestern could buy the share outright, but it would like its 374,000 Montana customers to be precommitted to covering other costs associated with the planned purchase, including an estimated $20 million in needed repairs, The Billings Gazette reports.

However, the application does not mention those repairs or say why Puget Sound wants to surrender its share of the plant, Nelson wrote in his comments, filed last Friday.

The benefit of coal-fired generation is eroding due to escalating maintenance and operating costs and competition from lower-priced natural gas electricity and renewable resources, Puget Sound Energy wrote in its application to the Washington regulators seeking authorization to sell its share of Colstrip Unit 4.

NorthWestern Energy said it would respond to Nelson's comments by the end of the week.