Not being one to put all my eggs in one alternative fuel basket, I've long been tracking progress in cellulosic ethanol development--the kind of biofuel made from tough, inedible plant parts including agricultural waste. But a new study out of Kansas State University is raining on the cellulosic parade.
Cellulosic ethanol has been called a next-generation biofuel because it doesn't require food crops like corn. Plus, in the short-term at least, it proposes turning waste into something useful. Previously I highlighted efforts to break down these notoriously challenging materials and still maintained my optimism. I know that even with the best science, ethanol still has drawbacks, but this kind of ethanol seems like a contender.
And now look. Humberto Blanco-Canqui, assistant professor at Kansas State University's Agricultural Research Center-Hays, published an article in a recent issue of Agronomy Journal (abstract) arguing convincingly that we shouldn't use crop residue to make cellulosic ethanol. Blanco-Canqui makes the case by combining his own original research and other peer-reviewed agricultural studies to show that removing agricultural waste such as stalks and leaves has negative effects on soil, the environment, and future crops. The residue actually sequesters carbon, helps keep the soil healthy, and is important for crop yield.
"Only a small fraction (about 25%) of residue might be available for removal, depending on soil type and climate," he writes in the article. "This small amount of crop residues is not economically feasible nor logistically possible." Ugh.
Maybe it shouldn't be surprising that this "waste" serves several purposes on the ground. Anyone with a compost pile can see that. As crushed as I am about this crimp in cellulosic ethanol development, it's better to find this out now, especially when there are several commercial-scale cellulosic ethanol production plants set to open soon in the United States.
The upshot is that Blanco-Canqui thinks that growing dedicated crops such as warm-season grasses like my personal favorite, switchgrass, would avoid the problem. These non-food crops have the advantage of growing in less-than-stellar soil while producing lots of biomass. So perhaps this parade is just being rerouted.
Photo Credit: Tim Hettler.
Tags: Agriculture, Forestry and Fishing, Alternative Fuels, Energy, Green Science
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