2011 Harvard Study Found Full Cost of Coal Very High

Published in 2011, this study estimates, in a conservative manner, the full life-cycle cost of the US's reliance on coal for electricity. Its main finding is that the true cost of coal for electricity is between 9 and 27 cents per kWh (best estimate: 18 cents/kWh), considerably more than competently developed wind power. Taxpayers are paying this price, although it doesn't show up on our electric bills.

The official study, through Wiley, is here. But, you can get it more easily  here.