No, that won't work. To "un-combust" the CO2 back into ethanol would take all the electricity you just produced from burning the coal (if not more, considering the inefficiency losses in the Rankine cycle). You don't get something for nothing. This is potentially a way of storing electrical energy gathered by other means, sure - but if that other means involved generation of CO2 by combustion, bolting on this process would be worse than useless.
