I too believe clean coal is a fool’s errand. But promising it and throwing money at it buys votes in every country where coal mining employs hundreds of thousands.

I’m guessing there will never be “clean coal.” Coal is attractive as a fuel only because it’s abundant, cheap, and easily storable for indefinite periods. If you spend enough money to make it “clean” it’s no longer cheap, and then the market will abandon it. One might argue that coal is something like tar sands. It’s feasible to combine natural gas with coal (or tar sand) and produce synthetic liquid hydrocarbon transportation fuels. Synthetic diesel or gasoline, which would be no more or less clean than petroleum based fuels. Coal might be thought of as a cheap high energy density storage medium for natural gas. Shell’s Pearl plant has already demonstrated direct conversion of natural gas to liquid diesel fuel is technically feasible and highly economical (diesel fuel production costs are about $0.50/gal). It’s likely that sort of process will always be cheaper than hydrogenating coal, but more of the energy is wasted in driving the process, and the wasted energy is pumping more CO2 into the air. The only way there will ever be significant amounts of “clean” coal is if government steals from the most productive parts of the economy and transfers what it stole to less productive parts of the economy. It’s unclear what, other than fear of jail or hell, could limit that sort of waste, fraud, and abuse. The churches and governments have acted in ways that vastly diminish the plausibility of those threats.