EPA loss in supreme court.

High Court Strikes Down EPA Limits on Mercury Emissions http://www.wsj.com/articles/high-court-strikes-down-epa-limits-on-mercury-emissions-1435590069
The EPA must consider the cost of compliance when coming up with rules. That's what the Supreme Court ruled.
Of course it is hard to estimate the cost of the pollutants, that have been going on for a couple centuries now.
With natural gas being so cheap, and most of the conversions already complete, the whole issue is rather mute point.
But it does set back EPA action on CO2 emissions, where is the coal lobby would like to consider the cost of externalities nonexistent.
Still in the absence of Congress and its inability to do anything, you have the problem of the Fed and the EPA trying to do the heavy lifting.