Fuel Miles and the Blend Wall: Costs and Emissions from Ethanol Distribution in the United States

Largely due to government programs motivated by climate change, energy security, and economic development goals, U.S. production of ethanol increased 10-fold from 1991 to 2009. National-level economic and environmental goals could be accomplished more efficiently by concentrating consumption of gasoline containing 10% ethanol (i.e., E10) near producers to minimize freight activity, as low-level ethanol-gasoline blends have not consistently outperformed ethanol-free gasoline in vehicle performance or tailpipe emissions. The portion of t-km potentially justified by the E10 blend wall increased from less than 40% to 80%, as the domestic transportation of ethanol increased 10-fold in metric ton-kilometers (t-km) from 2000 to 2009. However, 10 billion t-km took place annually from 2004 to 2009 for reasons other than the blend wall, as estimated by the authors. The result of this "unnecessary" transportation was more than $240 million in freight costs, 300,000 metric tons of CO₂-e emissions, 440 g of human intake of particulate matter (PM)2.5, and 90 million L of diesel consumption. The marginal savings from enabling Iowa to surpass E10 would have exceeded 2.5 g CO₂-e/MJ and $0.12/gallon of ethanol by 2009, as the next-closest customer was 1600 km away. Estimation of marginal transportation impacts from subnational policies, as well as benefits from policies encouraging concentrated consumption of renewable fuels is enabled by the use of a national network model.


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  • Accession Number: 01530797
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jul 3 2014 2:58PM