Silly question I know. A coal plant is a coal plant is a coal plant - still the dirtiest form of power generation known to us, no matter which way you look at it. But now that more and more people are uneasily waking up to the fact that the government are about to sanction a new generation of the things, suddenly we're knee-deep in spin about how environmentally friendly they could become. How surprising.
First there's been a great slew of CCS 'clean coal' stories. Carbon capture and storage may be theoretically feasible but it's expensive (up to twice the cost of unabated coal), technically complicated (involving deep cooling the CO2 into liquid form and creating a network to pump it out back under the North Sea where our oil and gas reserves originally resided) and commercially untried (so far no one is keen to pay for it themselves).
