As much as I believe that we are long overdue for a transition away from fossil fuels, the statement that "coal is not clean" is not absolutely true. The "clean coal" technology that is the buzzword politically is the process of scrubbing the exhaust output of power generation plants burning conventional coal. Clean coal is nearly an oxymoron, but no one I've seen has discussed converting coal to coke, which yields large amounts of methane (natural gas). When coal is baked in an oxygen-deprived oven, it yields large amounts of methane and reduces to a substance that is burned in blast furnaces to manufacture steel (coke). Since we have very little steel manufacturing left in the U.S., it would give us an export product to help balance the trade deficit. Coke furnaces require forced oxygen, and burn very cleanly compared to raw coal. My take is that the tooling required to scrub conventional coal would eliminate the economic advantage of using raw coal. Coal could be a benefit to the railroads and the economy in a green way if processed properly. Incidentally, there are many more substances than corn from which ethanol can be derived, and no one has discussed combining biomass and sewage to produce methane. Tapping the sewage output of Washington D.C. could probably get us to the 22nd century. The seeming lack of alternatives suggests itself to be another oil industry deception.