Transcript Slide 1
HC399 http://www.wired.com/science/pla netearth/magazine/15-10/ff_plant 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 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 Ethanol http://www.hotstocked.com/articles-img/small/corn_ethanol.jpg 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 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.jpg biofuelsdigest.com/.../2008/08/miscanthus.jpg 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 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 gasoline www.eco-cars-online.info www.all-creatures.org/hope/img/earth-light.jpg 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 gasoline www.livenowcoaching.org Pretreatment Hydrolysis Fermentation Distillation http://www.pacificethanol.net/ http://www.verenium.com/images/pic_research_cellulosic_ dia.gif 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 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 Microorganisms: Baker’s yeast (Saccharomyces cerevisiae) Z. mobilis Escherichia coli Dilemma: Ferment both hexose and pentose sugars into ethanol Biotechnology will play a 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 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 crops http://k41.pbase.com/v3/64/556764/1/49163116.gladiolifarmingbetweenpoplartrees 8886.jpg 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 Gasification Microbe Cellulose -------> CO, CO2, and hydrogen -------> Ethanol Through heating and chemical treatment, biomass made in to syngas Syngas can then be converted into ethanol http://simonwilliambaird.files.wordpress.com/2008/04/syngas_ brand.jpg E85: Flexible Fuel Vehicles Lignin from biomass can be used to create steam necessary for ethanol production Biomass could fuel powerplants www.cleanairchoice.org 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 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 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 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