OK, chemistry nerds, this one's for you. Some bright bulbs [1] over at Rutgers University and UNC Chapel Hill have discovered a way to make liquid fuel - diesel, in fact - out of solid lumps of good old-fashioned coal. What's that? You say it's been done before? Well, sure. Germany powered much of its World War II machinery [2] with coal turned to diesel by a handy bit of chemical voodoo known as Fischer-Tropsch synthesis, [3] in which sources like biomass, natural gas, or coal are heated to release carbon monoxide and hydrogen molecules, which are then reformed into, among other things, liquid diesel. (Pay attention; there will be a quiz.)

But whereas the original method produced a few too many not-very-useful medium-weight hydrocarbon molecules, the more efficient Rutgers method uses catalysts to rearrange a few atoms and turn those middleweights into higher-weight molecules. Voila: more liquid-diesel bang for your solid-source buck. And the Rutgers-UNC method inherently reduces much of the nasty particulate matter found in standard American diesel.

Diesel-powered engines typically run 30 percent more efficiently than unleaded models. According to the Energy Blog, [4] diesel moves 94 percent of all freight in the U.S. and 95 percent of all transit buses and heavy construction machinery, consuming approximately 56 billion gallons of diesel fuel per year. Meanwhile, America's sitting on a few trillion tons [5] of coal reserves.

So will coal-rich states like Montana [6] and Pennsylvania [7] become the new Bahrain and Saudi Arabia? Much debate [8] still rages over whether the environmental costs of coal-to-liquid's production - strip mining and acid runoff, potentially greater up-front energy use and higher carbon dioxide emissions than oil refining - outweigh the reportedly clean-burning benefits. Not only that, but some [9] see the push for so-called coal-to-liquid as a grand boondoggle [10] benefiting only the energy industry.