Switchgrass: the real deal
Posted on January 9, 2008
Filed Under All, Technology, Green Tech |
Switchgrass contains 5 times more energy than it takes to grow. Compare that to corn, which, despite the euphoria among farm-state politicians and farmers, only provides 30% more energy than is required to produce it. Taking corn out of the food supply for fuel also raises prices for food, as well: indeed, this year, there will be much less corn available for hungry nations (e.g. those in Africa) because of steep price increases.
The only problem with current cellulosic ethanol production is the production technology: no one has yet quite figured out a continuous production process where the finished cost rivals current U.S. gas prices. At issue is the cost of enzymes which are needed to turn cellulose (typically after an acid hydrolysis process) into sugars that can be processed into alcohol.
While the enzymes are coming down in price, cellulosic ethanol is still 4 or 5 times more expensive than gasoline, and requires a (relatively simple) modification in current vehicles. The switchgrass news (reported in the Proceedings of the National Academy of Sciences) is good, but there are lots of other cheap sources of cellulose: two-thirds of landfill refuse is cellulose. Either a cheaper process or sufficiently high gas prices are all it will take for cellulosic ethanol to make sense…
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