Cellulosic Bioethanol

Cellulosic bioethanol is a type of biofuel produced from the lignocellulose that comprises the fibrous bulk of plant matter. This form of ethanol would have the great advantage of coming from non-food plant materials such as corn stalks, switchgrass, wood chips, non-native plant occurrences, and landscaping waste; traditional starch-derived bioethanol comes from corn and other food crops. According to the US Department of Energy, a switch from burning gasoline to burning cellulosic ethanol could reduce GHG emissions by 85 percent (http://www.eere.energy.gov/biomass/news.html ). However cellulosic ethanol production requires a greater amount of materials processing than does production of traditional bioethanol or ethanol from fossil fuels (http://en.wikipedia.org/wiki/Cellulosic_ethanol  ). On balance, production of ethanol from starch may not reduce some GHG emissions at all (e.g. nitrous oxide) if it is not somehow produced sustainably (Crutzen et al. 2007); bioethanol releases more air pollutants per net energy gain than biodiesel (Hill et al. 2006). The current environmental advantages of using biodiesel over bioethanol (e.g. 12 versus 41 percent reduction in GHG, respectively) comes from lower agricultural inputs and more efficient conversion of raw materials to fuel during production. See “Biofuel.”

Citations:

Crutzen, P.J., A.R. Mossier, K.A. Smith, W. Winiwarter. 2007. Nitrous oxide release from agro-biofuel production negates global warming reduction by replacing fossil fuels. Atmospheric Chemistry and Physics 7:11191-11205.

Hill, J., E. Nelson, D. Tilman, S. Polaski, and D. Tiffany. 2006. Environmental, economic and energetic costs and benefits of biodiesel and ethanol biofuels.