Biofuels: Food versus Fuel? Dr. Tapsak, HSC203, x4893 National Teach-in on Global Warming, Feb. 5, 2009
How green are biofuels?
Interesting ethanol facts! In 1908, Ford’s Model T had a carburetor adjustment that allowed the vehicle to run on ethanol. In the 1930s, more than 2000 service stations in the Midwest sold ethanol made from corn. By the 1940s, WW2 prompted governments to commandeer whiskey distilleries for ethanol fuel production. During the 1970s oil crisis, ethanol was blended into gasoline to form gasohol (E10). accessed 2/3/09
How is ethanol currently produced from corn? Milling Liquefying the Cornmeal Enzyme Hydrolysis Yeast Fermentation Distillation Dehydration accessed 2/3/09
Where is ethanol currently produced?
Switch grass and wood byproducts contain fermentable sugars, but they are locked up in complex structures. Plant matter (biomass) consists of three key polymers: Cellulose (35 to 50%), hemicellulose (20 to 35%), and lignin (10 to 25%). accessed 2/3/09
How is ethanol currently produced from biomass? Mechanical Preprocessing Pretreatment Solid-Liquid Separation Fermentation of Hemicellulosic Sugars Enzyme Production Cellulose Hydrolysis Fermentation of Cellulosic Sugars (Glucose) Distillation Dehydration accessed 2/3/09
What are the challenges we face? According to Dr. David Pimental, Cornell University, powering the average U.S. automobile for one year on ethanol (blended with gasoline) derived from corn would require 11 acres of farmland. Ethanol can not be effectively transported by pipeline. More energy is required to produce ethanol than the energy that actually is in it. Ethanol subsidies are highly politicized. accessed 2/3/09