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United States Department of Agriculture

Agricultural Research Service

Title: Economics and Energy of Ethanol Production from Alfalfa, Corn, and Switchgrass in the Upper Midwest, Usa

Authors
item Vadas, Peter
item Barnett, Kenneth - UNIV OF WISCONSIN
item Undersander, Daniel - UNIV OF WISCONSIN

Submitted to: BioEnergy Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 9, 2008
Publication Date: March 10, 2008
Repository URL: http://www.ars.usda.gov/sp2UserFiles/Place/36553000/publications/2008-Vadas-BR-XXX-XXX.pdf
Citation: Vadas, P.A., Barnett, K.H., Undersander, D.J. 2008. Economics and energy of ethanol production from alfalfa, corn, and switchgrass in the Upper Midwest, USA. Bioenergy Research. 1:44-55.

Interpretive Summary: In the U.S., biomass crop systems will be needed to meet future ethanol production goals. We estimated production costs, profits, and energy budgets for three potential crop systems for the Upper Midwest: continuous corn, an alfalfa-corn rotation, and switchgrass. Our analysis emphasizes tradeoffs among crop systems. Corn may produce the most ethanol and net energy, but uses the most energy during production and has the greatest erosion and N leaching. Corn may have the greatest production costs, but can return the greatest profit. Comparatively, alfalfa-corn will produce less ethanol and net energy, but more efficiently and with less erosion and little N leaching. Production costs will be less for alfalfa-corn than continuous corn, but profits may also be less. Switchgrass will produce the least ethanol and net energy, but will do so most efficiently, and with little erosion. Nitrogen leaching will be less for switchgrass than corn, but greater than alfalfa-corn. Switchgrass may be the least expensive to produce, but may return a profit only if selling prices or yields are high.

Technical Abstract: In the U.S., biomass crop systems will be needed to meet future ethanol production goals. We estimated production costs, profits, and energy budgets for three potential crop systems for the Upper Midwest: continuous corn, an alfalfa-corn rotation, and switchgrass. Production costs, profits, and on-farm energy use were greatest for continuous corn, less for alfalfa-corn, and least for switchgrass. Energy to transport crops was similar for all crop systems. Both energy used to produce ethanol and energy output in ethanol was greatest for continuous corn, less for alfalfa-corn, and least for switchgrass. By-product energy outputs from distillers grains and alfalfa leaf meal was 30-40% greater for alfalfa-corn than continuous corn. Switchgrass had no by-products. Net energy produced (outputs - inputs) was greatest for continuous corn, followed by alfalfa-corn, and then switchgrass. Efficiency of energy production (outputs / inputs) was greatest for switchgrass, followed by alfalfa-corn, and then continuous corn. Our analysis emphasizes tradeoffs among crop systems. Corn may produce the most ethanol and net energy, but least efficiently and with the greatest erosion and N leaching. Corn may have the greatest production costs, but return the greatest profit. Comparatively, alfalfa-corn will produce less ethanol and net energy, but more efficiently and with less erosion and little N leaching. Production costs will be less for alfalfa-corn than continuous corn, but profits may also be less. Switchgrass will produce the least ethanol and net energy, but will do so most efficiently, and with little erosion. Nitrogen leaching will be less for switchgrass than corn, but greater than alfalfa-corn. Switchgrass may be the least expensive to produce, but may return a profit only if selling prices or yields are high

Last Modified: 7/30/2014
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