Last year we had a good laugh at politicans who were saying America could be powered by "clean coal." What they were talking about, what they are still talking about, is carbon capture and storage (or sequestration). CO2 would be captured at the source, then -- disposed of. Somehow.
Of course this does nothing about the other part of the coal idiocy, the input side. The environmental disaster caused in the course of mining coal is enough by itself to take coal generated electricity off the table.