Ethanol production: Energy and economic issues related to U.S. and Brazilian sugarcane

David Pimentel*, Tad Patzek

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

55 Scopus citations


For a thorough and up-to-date evaluation of all the fossil energy costs of ethanol production from sugarcane in both the U.S. and Brazil, every energy input in the biomass production and ultimate conversion process must be included. In this study, more than 12 energy inputs in average U.S. and Brazilian sugarcane production are evaluated. Then in the fermentation/ distillation operation, nine more fossil fuel inputs are identified and included. Some energy and economic credits are given for the bagasse to reduce the energy inputs required for steam and electricity. Based on all the fossil energy inputs in U.S. sugarcane conversion process, a total of 1.12 kcal of ethanol is produced per 1 kcal of fossil energy expended. In Brazil a total of 1.38 kcal of ethanol is produced per 1 kcal of fossil energy expended. Some pro-ethanol investigators have overlooked various energy inputs in U.S. and Brazilian sugarcane production, including farm labor, farm machinery, processing machinery, and others. In other studies, unrealistic low energy costs were attributed to such energy inputs, as nitrogen fertilizer, insecticides, and herbicides. Both the U.S. and Brazil heavily subsidize ethanol production. Thus billions of dollars are invested in subsidies and this significantly increases the costs to the consumers. The environmental costs associated with producing ethanol in the U.S. and Brazil are significant but have been generally overlooked. The negative environmental impacts on the availability of cropland and freshwater, as well as on air pollution and public health, have yet to be carefully assessed. These environmental costs in terms of energy and economics should be calculated and included in future ethanol analyses so that sound assessments can be made. In addition, the production of ethanol in the U.S. and Brazil further confirms that the mission of converting biomass into ethanol will not replace oil. This mission is impossible. General concern has been expressed about taking food crops to produce ethanol for burning in automobiles instead of using these crops as food for the many malnourished people in the world. The World Health Organization reports that more than 3.7 billion humans are currently malnourished in the world-the largest number of malnourished ever in history.

Original languageEnglish (US)
Pages (from-to)235-242
Number of pages8
JournalNatural Resources Research
Issue number3
StatePublished - Sep 2007
Externally publishedYes

Bibliographical note

Funding Information:
We would like to thank the following people for their valuable comments and suggestions on earlier drafts of this manuscript: Andrew B. Ferguson, Optimum Population Trust, Oxon, UK; Mario Giampietro, Istituto Nazionale di Ricerca per gli Alimenti e Nutrizione (INRAN), Rome, IT; Matthew Farwell, Alternative Energy, Energy, Nanotechnology, Palo Alto, CA: Marcelo Dias de Oliveira, University of Florida, Gainesville, FL; Odo Primavesi, Empresa Brasileira de Pesquisa Agro-pecuária (Embrapa), Brazil; Thomas Standing, San Francisco Public Utilities Commission, San Francisco, CA; Sergio Ulgiati, Department of Chemistry, University of Siena, Italy; Walter Youngquist, Petroleum Consultant, Eugene, OR. This research was supported in part from a grant from the Podell Emertii award at Cornell University.


  • Converting biomass
  • Energy costs
  • Environmental costs
  • Subsidization

ASJC Scopus subject areas

  • General Environmental Science


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