Is There Some Light at the End of Coal's Long, Dark Tunnel? - NYTimes.com
Some think that the only way to clean up coal is to stop burning it altogether. Now a handful of researchers and companies are pursuing a technology to do just that, but one that has the potential of keeping part of the nation's economy coal-fired.
They are skipping the burning step. "Direct carbon" fuel cells efficiently produce electricity straight from the carbon source, which can be anything from coal to coconut shells.
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... direct carbon fuel cells (DCFCs) -- an umbrella term that encompasses a range of fuel cell technologies -- convert carbon sources to electricity in a single reaction step, just as current fuel cells do with hydrogen. Under various schemes that pulverize coal and feed it into the fuel cell in a slurry of molten salt or other superheated material, the carbon in the coal reacts in the cell to produce a moving stream of electrons, or electricity.
Researchers estimate that real-world efficiencies of DCFCs could approach up to 70 percent, the highest of any fuel cell class.