Published March 18, 2012
By Huw Evans
A comprehensive study has revealed that E85 ethanol blended fuel produced from dry mills has a significantly worse environmental impact than does straight petroleum-based gasoline.
Conducted by research teams from the University of California at Santa Barbara, the University of Minnesota, and the Technical University of Troyes, France, the study covered 19 American corn-belt states, and analyzed the full effect from 12 different environmental factors.
The study, published in the journal Environmental Science and Technology and reported also by GreenCarCongress.com,factored different environmental impacts aggregated by weights developed by the National Institute of Standards and Technology. It went so far as to include consideration for such aspects as eutrophication and extensive irrigation required for growing corn.
One simple definition for eutrophication is, “an increase in the rate of supply of organic matter in an ecosystem.”
Overall, the study concluded the environmental impact from E85 is 23 percent higher on average than gasoline. If greenhouse gas emissions from indirect land use are also factored into the equation, the impact rises still further, to an average of 33 percent. In other words, the researchers accounted for greenhouse gas emissions resulting from such ancillary factors as using fossil-fueled equipment to harvest the corn, convert it into ethanol and then ship the end product its final destination.
To reach these findings, the team’s analysis had also compared a range of environmental impacts from gasoline to ethanol produced in 2005 and considered aspects such as feedstock production, feedstock shipping to the refinery, refining/conversion as well as shipment of the final fuel to the refueling station and use in the vehicle.
The study used the Argonne National Laboratory’s Greenhouse Gases, Regulated Emissions and Energy Use in Transportation (GREET) model. This is a model that examines the amount of fuel required for the average gasoline and flex-fuel vehicle over a distance of about 0.62 miles (1 kilometer). It takes into account the extent to which crude oil is imported and refined domestically, and compares E85’s benefits against its drawbacks.
Where E85 is believed to be better as a fuel is in terms of such aspects as potential ecological toxicity, effect on global warming and fossil energy consumption. Its outweighing drawbacks include land use, eutrophication, irrigation/water use and a much lower energy content per measured unit than gasoline, with the net result being, as mentioned, that pros are outweighed by cons.
In short, the study concluded E85 simply shifts the environmental impact elsewhere, rather than actually reducing it.