Security

DARPA Hearts <cite>WIRED</cite>, Bio-Fuels

WIRED talks; the Pentagon listens. Just last month, the magazine declared that the cellulose found in plant cell walls to be "a potentially limitless source of energy" and the "one molecule [that] could cure our addiction to Middle East oil" — if only we could "turn trees into ethanol… at a price people are willing […]

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WIRED talks; the Pentagon listens. Just last month, the magazine declared that the cellulose found in plant cell walls to be "a potentially limitless source of energy" and the "one molecule [that] could cure our addiction to Middle East oil" -- if only we could "turn trees into ethanol... at a price people are willing to pay."

Now, Darpa, the Pentagon's blue sky research arm, has announced a new program to try to turn cellulosic plant matter into jet fuel, for less than $3 a gallon.

The agency already has a project underway to turn crops like corn more efficiently oils into biofuels. But, as WIRED's Evan Ratliff notes, it's not exactly a long run solution.

*Corn ethanol is easier to produce than the cellulosic kind (convert the sugar to alcohol and you're basically done), but it generates at best 30 percent more energy than is required to grow and process the corn — hardly worth the trouble. Plus, the crop's fertilizer- intensive cultivation pollutes waterways, and increased demand drives up food costs (corn prices doubled last year). And anyway, the corn ethanol industry is projected to produce, at most, the equivalent of only 15
billion gallons of fuel by 2017. "We can't make 35 billion gallons'
worth of gasoline out of ethanol from corn," says Dartmouth engineering and biology professor Lee Lynd, "and we probably don't want to."
*

Cellulosic ethanol, in theory, is a much better bet. Most of the plant species suitable for producing this kind of ethanol — like switchgrass, a fast- growing plant found throughout the Great Plains, and farmed poplar trees — aren't food crops. And according to a joint study by the US Departments of Agriculture and Energy, we can sustainably grow more than 1 billion tons of such biomass on available farmland, using minimal fertilizer. In fact, about two-thirds of what we throw into our landfills today contains cellulose and thus potential fuel. Better still: Cellulosic ethanol yields roughly 80 percent more energy than is required to grow and convert it.