ABSTRACT
Demand for ethanol as a motor fuel has increased owing to
its use as a fuel oxygenate and discontinued use of methyl
tertiary butyl ether (MTBE). This was driven largely by the
Clean Air Act amendment of 1990, which requires the use
of oxygenated fuel and reformulated gasoline to reduce
carbon monoxide and other pollutants. The Energy Policy
Act of 2005 established a Renewable Fuel Standard, which
called for ethanol production to reach 28.4 billion L per
year by 2012. Ethanol production has increased more than
fourfold from 3.4 billion L per year in 1990 to more than
14.8 billion L per year in 2005.[1] Corn used for fuel
ethanol increased more than sixfold from 8.8 million
tonnes in 1990 to 54.6 million tonnes in 2006 (Fig. 1).
In 2006, there were 106 ethanol production facilities
having a capacity of 19.3 billion L per year in operation
and 46 new construction projects in progress.[1] Much of
the fuel ethanol production capacity in the United States is
concentrated inMidwestern states, which have large inven-
tories of corn.
