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Energy Balance of Corn Ethanol Results (Btu in EtOHMinus by htt39969

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									Energy Balance of Corn Ethanol Results
(Btu in EtOH Minus Btu Used)

                                 40,000


                                 30,000
                                                                    Lorenz and Morris      Agri. Canada
                                                                                                         Shapouri et al.
                                 20,000                                                                Kim and
                                                                                           Wang et al.    Dale       Wang
 Net Energy Value (Btu/gallon)




                                           Marland and Turhollow                                            Graboski
                                                                     Shapouri et al.
                                 10,000


                                      0

                                            Ho
                                 -10,000
                                                       Keeney and DeLuca

                                 -20,000


                                 -30,000

                                                    Pimentel                                          Pimentel
                                 -40,000
                                       1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004



                                                                                        Source: M. Wang (2003)
Ethanol Net Energy Value - Summary of Studies

  Authors and Date                 NEV [Btu]
 Pimentel (1991)                      -33,517

 Pimentel (2001)                     -33,562

 Keeney and DeLuca (1992)             -8,438

 Marland and Turhollow (1990)         18,154

 Lorenz and Morris (1995)             30,589

 Ho (1989)                            -4,000

 Agri.and Agri-Food, CAN (1999)       29,826

 Wang et al. (1999)                   22,500

 Shapouri et al. (1995)               20,436

 Kim and Dale (2002)              23,886 – 35,463
Why do Pimentel’s analyses stand out?

• His corn yields date from pre-1992
• His value for energy required to produce ethanol
  and the ethanol yield date from pre-1980
• His figures for energy to produce fertilizer are
  1990 world-wide values, not recent U.S. values
• He assumes all corn is irrigated (only 16% is)
  – virtually no irrigated corn is converted to ethanol
• He does not properly assign an energy credit for
  the high protein DDGS co-product
                                          Yield of Corn with Time
                                 Linearly increasing since 1950 at 1.7bu/acre/yr

                   150.0

                   140.0

                   130.0
Bushels per Acre




                   120.0

                   110.0

                   100.0

                    90.0

                    80.0

                    70.0

                    60.0
                           70   72   74    76   78     80   82   84    86   88   90   92   94   96     98   '00




                                                     Source: Professor Bruce Dale, Mich. State Univ.
                         U.S. Corn Output per Pound of Fertilizer Used
                                              (3-year Moving Average)
                         0.65
                                                                                    Precision
                                                                                    farming, etc.?
                         0.60
                                                Some earlier studies
                         0.55
                                                showed negative energy
Bushels/lb. Fertilizer




                                                balance for corn ethanol
                         0.50

                         0.45

                         0.40

                         0.35

                         0.30
                                1965   1970    1975    1980     1985       1990   1995   2000        2005


                                                      Source: USDA data cited by M. Wang (2003)
         Technology Has Reduced Energy Use Intensity
         of Modern Ethanol Plants

             70,000                                                                         1980s
             60,000                                                                         2000s

             50,000
Btu/Gallon




             40,000

             30,000

             20,000

             10,000

                 0
                                 Wet Mill                                  Dry Mill

                      Source: from Argonne’s discussions with ethanol plant designers and
                      recent USDA data (Wang, 2003)

								
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