How green are biofuels?
Post on 24-Feb-2016
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Biofuels: Food versus Fuel?
Dr. Tapsak, HSC203, x4893National 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).
http://www.nesea.org/greencarclub/factsheets_ethanol.pdf, accessed 2/3/09
How is ethanol currently produced
from corn?
• Milling • Liquefying the Cornmeal • Enzyme Hydrolysis • Yeast Fermentation • Distillation• Dehydration
https://www.eere-pmc.energy.gov/PMC_News/images/ethanolmythpic.jpg, 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%).
http://genomicsgtl.energy.gov/benefits/cellulosicethanol.shtml, 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
http://genomicsgtl.energy.gov/benefits/cellulosicethanol.shtml, 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.
http://genomicsgtl.energy.gov/benefits/cellulosicethanol.shtml, accessed 2/3/09
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