An estimation of potential production of agri -based ethanol and its contribution to transportation emissions

This study seeks to evaluate the relative merits of ethanol as a transportation fuel. Specifically, the study addresses: (i) the production potential for latent ethanol (i.e. ethanol which could be produced from stillage feedcrops without modification of the current agricultural system), (ii) the amount of gasoline which could be displaced by this latent ethanol in the internal combustion engine (ICE) transportation fleet, (iii) the emission benefits from use of ethanol as a transportation fuel in ICE vehicles relative to gasoline and an alternative fuel contender methanol, (iv) the net carbon, and other, emissions due to ethanol production and use, (v) comparison of ethanol, methanol and gasoline in terms of their applicability to fuel cell operations, and (vi) the potential for latent ethanol to support current transportation needs if utilized in fuel cell powered vehicles.;This study demonstrates that it is possible to produce large quantities of fuel ethanol within the current U. S. agricultural system. Although latent ethanol production capacity is not significant on a national scale when it is assumed that the fuel will be used in ICE vehicles, because latent ethanol production potential is regionally distributed, there may be potential for regionally significant use of ethanol as a road transportation fuel. As an end-use fuel ethanol has lower overall emissions than gasoline and compare favorably to methanol. When adjusted to reflect emissions associated with feedstock cultivation and ethanol processing, however, the fuel can no longer be considered completely carbon neutral. All three fuels perform similarly in fuel cells, which are superior to ICE systems in terms of energy released and performance delivered for each unit of emitted species. Assuming full penetration of fuel cell vehicles into the road transportation fleet annual latent ethanol production is sufficient to meet 61.6 days of current automotive fuel demands in the U.S.