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Transcript of HC399 netearth/magazine/15-10/ff_plant.
Cellulosic Ethanol and E85 Vehicles
HC399
http://www.wired.com/science/planetearth/magazine/15-10/ff_plant
Introduction
Ethanol produced by fermenting plant sugars
Worldwide, ethanol is the most commonly used biofuel for transportation
Cellulosic ethanol has many advantages over corn-based ethanol
Applications: E85 Flexible Fuel Vehicles
Ethanol Sources
Corn Currently, primary ethanol
source in US (Midwest) 10% ethanol/90% gasoline
blend (burns cleaner and increases octane rating)
Sugar Cane 20% of transportation fuel
market is from ethanol 7/10 new cars sold in Brazil
are flex fuel $.81/gallon
Cellulosic Ethanolhttp://www.hotstocked.com/articles-img/small/corn_ethanol.jpg
Limitations of Corn-based ethanol
High-energy input Environmental Impact:
Fertilizer and Pesticide Use Soil Erosion Farm machinery and transportation
requirement Limited supply
DOE: Max ethanol from corn: 12 billion gallons/year Competes with food supply Alexander Farrell of UC Berkeley:
Corn-based ethanol instead of gasoline reduces greenhouse gas emissions only about 18% (88% for cellulosic ethanol).
http://www.umassvegetable.org/images/soils_crops_pest_mgt/crop/corn5.jpg
Cellulosic Ethanol
Agricultural, industrial, forest, yard and house hold waste: wood, corn stalks, non-edible parts of food crops, yard waste
Energy Crops: Switchgrass, Poplar Trees, Miscanthus
No commercial cellulosic-ethanol plants today
Energy Independence and Security Act of 2007: 36 billion gallons of renewable transportation fuels in the U.S. by 2022.
msnbcmedia3.msn.com/j/msnbc/Components/Photos www.vtnews.vt.edu/images/poplar250.jpgbiofuelsdigest.com/.../2008/08/miscanthus.jpg
Biomass Components
Cellulose is the most abundant organic compound on Earth Glucose molecules linked together Cell wall component Approximately 44% of plant
Hemicellulose Composed of xylose and other pentoses Approximately 30% of plant
Lignin Inhibits conversion of cellulose to ethanol Necessary for structural support and pest
resistance 26% of biomass
http://en.wikipedia.org/wiki/Cellulose
Why Cellulosic Ethanol?
US could convert 1.3 billion dry tons of biomass a year into 60 billion gallons of ethanol, enough to replace 30% of transportation fuel
Lower energy input and low cost biomass: produced from plant waste or specialized crops
Reduce greenhouse gas emission by 88% compared to gasoline
Cellulose sources take in carbon dioxide
Demand for ethanol could increase further if methyl tertiary butyl ether (MTBE) is eliminated from gasolinewww.eco-cars-online.info
www.all-creatures.org/hope/img/earth-light.jpg
Hurdles of Cellulosic Ethanol
Producing cellulosic ethanol at a competitive price
Compared to corn starch and sugar feedstocks, cellulosic materials is harder to break down into fermentable sugars Requires two additional steps: pretreatment
and cellulose hydrolysis Infrastructure Industrial scale-up and speed
No current commercial production Contains approximately 30% less
energy/gallon than gasolinewww.livenowcoaching.org
Overview of Cellulosic Ethanol Production
Pretreatment Hydrolysis Fermentation Distillation
http://www.pacificethanol.net/
Pretreatment
Need to extract cellulose from lignin and other plant compounds
Acid and Steam Break hemicellulose component of biomass
into simple sugars
Dilemmas: Difficult to separate cellulose from other plant
material such as lignin Acid and Steam require energy to produce Acid reacts with sugar reducing yield by 10% and
creates byproducts that inhibit fermentation
Cellulose Hydrolysis
Breaks cellulose into glucose Common Methods
Acid hydrolysis Enzymatic hydrolysis: cellulase
Dilemmas: Hydrolysis can create byproducts that
inhibit enzymes Acid generally can’t be re-used
www.globalwarmingart.com
Fermentation
Microorganisms: Baker’s yeast (Saccharomyces
cerevisiae) Z. mobilis Escherichia coli
Dilemma: Ferment both hexose and pentose
sugars into ethanol
Research to Improve Cellulosic Ethanol Production
Biotechnology will playa principal role in advancing cellulosic ethanol production
Goals: Improve cellulosic feedstock Increase efficiency of biomass to ethanol
conversion▪ Improve enzymes and microbes ability to
create ethanol through fermentation▪ Much focus on optimizing fermentation
http://en.wikipedia.org/wiki/Cellulosic_ethanol
Tree Biotechnology
Genetic Engineering of Poplar trees to contain lower levels of lignin Maximum of 50% reduction
of lignin Controversy of Genetic
Engineering Similar projects in
switchgrass and other potential energy cropshttp://k41.pbase.com/
v3/64/556764/1/49163116.gladiolifarmingbetweenpoplartrees8886.jpg
Genetic Engineering of Microbes Baker’s Yeast:
Can only covert hexoses to ethanol Genetically engineered to convert both hexoses
and pentoses Convert sugar into ethanol at a much faster rate
than bacteria. E. coli: insert genes so fermentation product is
ethanol instead of lactic acid and acetic acid Bacteria: E.coli and Z. mobilis:
GE to convert 90-95% of biomass sugars into ethanol
Downside: low tolerance of ethanol wineserver.ucdavis.edu
Thermochemical
Cellulose -------> CO, CO2, and hydrogen -------> Ethanol
Through heating and chemical treatment, biomass made in to syngas
Syngas can then be converted into ethanol
Microbe
Gasification
http://simonwilliambaird.files.wordpress.com/2008/04/syngas_brand.jpg
Ethanol Applications
E85: Flexible Fuel Vehicles
Lignin from biomass can be used to create steam necessary for ethanol production
Biomass could fuel powerplants
www.cleanairchoice.org
E85 Vehicles 85% ethanol/ 15% gasoline
Lower % ethanol in winter so vehicle can start
Over 6 million FFVs on road in US
General Motors and Ford say that half their car production will be flexible fuel by 2012
Roughly 1000 E85 stations Concentrated in Midwest E85 Stations near Corvallis (11 within 200 miles):
About 28 mi. State of Oregon DAS Motor Pool, Salem 1100 Airport Rd. SE Salem , OR 97301 Government owned vehicles only.
About 46 mi. SeQuential Biofuels 86714 McVay Hwy. Eugene , OR 97405
About 50 mi. Leather's Shell Truck Stop 12334 Ehlen Rd NE Aurora , OR 97002
cw50detroit.com/projectgreen
Comparison to Gasoline
Cost of E85 fuel is less than gasoline; cost per mile is similar
Comparable power and acceleration Environmental
Greenhouse gas emission reduction▪ Greater reduction for cellulosic ethanol than corn-
based ethanol Decrease in benzene (carcinogen) and
carbon monoxide Increase in acetaldehyde (toxic pollutant)
and formaldehyde
Conclusion
Further advances in research and development of cellulosic ethanol could make it a viable alternative fuel
Low cost biomass, but need to reduce production cost
E85 vehicles: E85 burns cleaner than gasoline and reduces greenhouse gas emissions
Lithium Ion Plug-in hybrids that run off E85
http://gas2.org
Bibliography:
http://www.afdc.energy.gov/afdc/ethanol/e85.html http://www.energy.ca.gov/research/renewable/biomass/ethanol
/index.html Http://www.nrel.gov/biomass/pdfs/40742.pdf http://www.energy.gov/news/4827.htm http://www.ethanolrfa.org/resource/cellulosic/ http://www.sciencemag.org/cgi/content/full/315/5818/1488 http://
www.epa.gov/smartway/growandgo/documents/factsheet-e85.htm
http://www.e85refueling.com/ http://yaleglobal.yale.edu/display.article?id=6817 http://www.eia.doe.gov/oiaf/analysispaper/biomass.html http://
www.ers.usda.gov/Publications/FDS/2007/05May/FDS07D01/fds07D01.pdf