Sierra Club and the Montana Environmental Information Center filed suit this week against coal-powered Colstrip Generating Facility owners for violations of the Clean Air Act.  The environmental groups have accused Warren Buffett's Berkshire Hathaway-(NYSE:BRK-B) (NYSE:BRK-A) owned PacifiCorp, PPL (NYSE:PPL), and additional owners, of "continued operation of Colstrip after illegal alterations [were] made without modernizing pollution controls." 

The facility began commercial operation in 1975, and currently has a 2,094 MW generating capacity.  Speaking on behalf of Sierra Club's Beyond Coal campaign, Director Bruce Nilles noted:

Today's legal action is the latest in our nationwide campaign targeting owners of the nation's aging coal fleet who continue to skirt their legal obligations. It's our national priority at the Sierra Club to uphold the health and environmental safeguards promised by the Clean Air Act for more than three decades. When coal-owning utilities can no longer dump their pollution on unsuspecting customers for free, they realize sticking with coal is a gamble they can't afford to risk. 

The environmental groups are seeking damages of up to $37,500 a day since the plant first underwent major alterations in 1992,  or approximately $300 million in total .