Document Detail


Emissions savings in the corn-ethanol life cycle from feeding coproducts to livestock.
MedLine Citation:
PMID:  20176820     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Environmental regulations on greenhouse gas (GHG) emissions from corn (Zea mays L.)-ethanol production require accurate assessment methods to determine emissions savings from coproducts that are fed to livestock. We investigated current use of coproducts in livestock diets and estimated the magnitude and variability in the GHG emissions credit for coproducts in the corn-ethanol life cycle. The coproduct GHG emissions credit varied by more than twofold, from 11.5 to 28.3 g CO(2)e per MJ of ethanol produced, depending on the fraction of coproducts used without drying, the proportion of coproduct used to feed beef cattle (Bos taurus) vs. dairy or swine (Sus scrofa), and the location of corn production. Regional variability in the GHG intensity of crop production and future livestock feeding trends will determine the magnitude of the coproduct GHG offset against GHG emissions elsewhere in the corn-ethanol life cycle. Expansion of annual U.S. corn-ethanol production to 57 billion liters by 2015, as mandated in current federal law, will require feeding of coproduct at inclusion levels near the biological limit to the entire U.S. feedlot cattle, dairy, and swine herds. Under this future scenario, the coproduct GHG offset will decrease by 8% from current levels due to expanded use by dairy and swine, which are less efficient in use of coproduct than beef feedlot cattle. Because the coproduct GHG credit represents 19 to 38% of total life cycle GHG emissions, accurate estimation of the coproduct credit is important for determining the net impact of corn-ethanol production on atmospheric warming and whether corn-ethanol producers meet state- and national-level GHG emissions regulations.
Authors:
Virgil R Bremer; Adam J Liska; Terry J Klopfenstein; Galen E Erickson; Haishun S Yang; Daniel T Walters; Kenneth G Cassman
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2010-02-19
Journal Detail:
Title:  Journal of environmental quality     Volume:  39     ISSN:  0047-2425     ISO Abbreviation:  J. Environ. Qual.     Publication Date:    2010 Mar-Apr
Date Detail:
Created Date:  2010-02-23     Completed Date:  2010-04-22     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0330666     Medline TA:  J Environ Qual     Country:  United States    
Other Details:
Languages:  eng     Pagination:  472-82     Citation Subset:  IM    
Affiliation:
Dep. of Animal Science, University of Nebraska, Lincoln, NE, USA.
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MeSH Terms
Descriptor/Qualifier:
Air Pollution*
Animal Feed*
Animal Husbandry
Animals
Biofuels*
Cattle
Dairying
Ethanol / chemical synthesis
Greenhouse Effect
Swine
Zea mays / chemistry
Chemical
Reg. No./Substance:
0/Biofuels; 64-17-5/Ethanol

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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