Friday, April 9, 2010

Cellulosic ethanol dealt a blow



Analysis by Alyssa Danigelis | Mon Apr 5, 2010 06:37 PM ET

CornNot 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 Ihighlighted 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.


Energy crops impact environmental quality

April 4, 2010

Crop residues, perennial warm season grasses, and short-rotation woody crops are potential biomass sources for cellulosic ethanol production. While most research is focused on the conversion of cellulosic feeedstocks into ethanol and increasing production of biomass, the impacts of growing energy crops and the removal of crop residue on soil and environmental quality have received less attention. Moreover, effects of crop residue removal on soil and environmental quality have not been compared against those of dedicated energy crops.

Ads by Google

Source - Setting A New, Common Standard For Exchange Traded Products (ETP/ETFs) -

In the March-April 2010 issue of Agronomy Journal, published by the American Society of Agronomy, Dr. Humberto Blanco reviewed the impacts of crop residue removal, warm season grasses, and short-rotation woody crops on critical soil properties, carbon sequestration, and water quality as well as the performance of energy crops in marginal lands. The review found that crop residue removal from corn, wheat,and grain sorghumcan adversely impact soil and environmental quality. Removal of more than 50% of crop residue can have negative consequences for soil structure, reduce soil organic carbon sequestration, increase water erosion, and reduce nutrient cycling and crop production, particularly in erodible and sloping soils.

"Crop residue removal can make no-till soils a source rather than a sink of," says Blanco, even at rates lower than 50%. Residue removal at rates of less than 25% can cause loss of sediment in runoff relative to soils without residue removal. To avoid the negative impacts on soil, perhaps only a small fraction of residue might be available for removal. This small amount of crop residues is not economically feasible nor logistically possible. Blanco recomends developing other alternative biomass sources for cellulosic ethanol production.

An alternative to crop residue removal is growing warm season grasses and short-rotation woody crops as dedicated energy crops. These crops can provide a wide of range of ecosystems services over crop residue removal. Available data indicate that herbaceous and woody plants can improve soil characteristics, reduce soil water and wind erosion, filter pollutants in runoff, sequester soil organic carbon, reduce net emissions of greenhouse gases, and improve wildlife habitat and diversity.

Whereas removal reduces carbon concentration, dedicated energy crops can increase soil organic carbon concentration while providing biofuel feedstock. Because of their deep root systems, warm season grasses also promote long-term in deeper soil profile unlike row crops.

Growing dedicated energy crops in marginal and abandoned lands instead of prime agricultural fields will further benefit the soil and environment. Warm season grasses can grow in nutrient-depleted, compacted, poorly drained, acid, and eroded soils. Herbaceous and woody energy crops cannot replace natural forest and native prairie lands, but well-managed dedicated energy crops may provide a myriad of benefits to and environment while supplying much needed feedstocks for cellulosic . Developing the next generation of biofuels will not only require new technologies to transform it into fuel, but new agricultural methods for growing it.

More information: View the abstract at

Provided by American Society of Agronomy

My Privacy...

No comments:

Post a Comment

Biofuels are a wide range of fuels which are in some way derived from biomass.

Your idea?