Shutting down and cleaning up the two oldest units at the Colstrip power plant in southeast Montana would cost $130 million to $200 million.

That's the estimate provided by Washington-based Puget Sound Energy, which owns half of Colstrip Units 1 and 2. The company says the two coal-fired power plants can be shuttered and dismantled for $49.7 million. Cleaning up the contaminated water and coal waste at the site will take another $85 to $142.7 million.

The Billings Gazette reports that this is the first time since the debate about shuttering Colstrip began that real numbers have been put to paper.