The Energy Balance of Corn Ethanol: An Update

Studies conducted since the late 1970s have estimated the net energy value (NEV) of corn ethanol. However, variations in data and assumptions used among the studies have resulted in a wide range of estimates. This study identifies the factors causing this wide variation and develops a more consistent estimate. We conclude that the NEV of corn ethanol has been rising over time due to technological advances in ethanol conversion and increased efficiency in farm production. We show that corn ethanol is energy efficient as indicated by an energy output:input ratio of 1.34.

[1]  A. Weinberg,et al.  Oak Ridge National Laboratory. , 1949, Science.

[2]  R. Herendeen,et al.  Gasohol: Does It or Doesn't It Produce Positive Net Energy? , 1979, Science.

[3]  Biological Energy Resources. , 1980 .

[4]  Folke Dovring,et al.  Energy Used for Fertilizers , 1980 .

[5]  R. Cline-Cole,et al.  Food, Energy and Society. , 1982 .

[6]  Paul R. Blankenhorn,et al.  Net financial and energy analyses for producing Populus hybrid under four management strategies, first rotation, June 1985 , 1984 .

[7]  H. Taylor,et al.  Fertilizer Use and Price Statistics, 1960-91 , 1987 .

[8]  M. Deluchi,et al.  Emissions of greenhouse gases from the use of transportation fuels and electricity , 1991 .

[9]  Gregg Marland,et al.  CO2 emissions from the production and combustion of fuel ethanol from corn , 1991 .

[10]  Robert D. Perlack,et al.  Emissions of C02 from energy crop production , 1991 .

[11]  David Pimentel,et al.  Ethanol fuels: Energy security, economics, and the environment , 1991 .

[12]  Dennis R. Keeney,et al.  Biomass as an energy source for the midwestern U.S. , 1992 .

[13]  Noel D. Uri,et al.  Energy efficiency, technological change and the dieselization of agriculture in the United States , 1992 .

[14]  Corn: State-Level Production Costs, Characteristics, and Input Use, 1991 , 1994 .

[15]  James A. Duffield,et al.  Estimating the net energy balance of corn ethanol. Agricultural economic report , 1995 .

[16]  D. L. Morris.  How Much Energy Does It Take to Make a Gallon of Ethanol , 1995 .

[17]  Industrial uses of agricultural materials. Situation and outlook report, July 1997 , 1997 .

[18]  Michael Wang,et al.  Effects of Fuel Ethanol Use on Fuel-Cycle Energy and Greenhouse Gas Emissions , 1999 .