What Is a Biofuel?
A biofuel is a transportation fuel derived from renewable resources such as plant biomass or municipal wastes that replaces or reduces the quantity of fossil fuel present in the U.S. transportation fuel mix.
The EPA’s Renewable Fuel Standard requirement for 2009 calls for 11.1 billion gallons (10.21 percent of U.S. transportation fuels), which includes 0.5 billion gallons of renewable biodiesel, to be used in the United States. Currently, the U.S. biofuel supply relies largely on ethanol produced from Midwest corn. Other biofuels that play a smaller role include sugarcane ethanol imported from Brazil, biodiesel from U.S. soybeans, and ethanol from U.S. sorghum.
Biofuels can be made from cellulosic biomass – plant matter composed primarily of inedible cellulose fibers that form the stems and branches of most plants. Crop residues (such as corn stalks, wheat straw and rice straw), wood waste, and even municipal solid waste are potential sources of cellulosic biomass. Dedicated energy crops, such as switchgrass or fast-growing trees, are also promising cellulose sources because they can be sustainably produced in many regions of the United States.
The Energy Independence and Security Act of 2007 categorized biofuels and conventional, advanced, and cellulosic:
The term “conventional biofuel” means renewable fuel that is ethanol derived from corn starch.
“Advanced biofuel” means renewable fuel, other than ethanol derived from corn starch, that has lifecycle greenhouse gas emissions that are at least 50 percent less than baseline lifecycle greenhouse gas emissions.
“Cellulosic biofuel” means renewable fuel derived from any cellulose, hemicellulose, or lignin that is derived from renewable biomass and that has lifecycle greenhouse gas emissions that are at least 60 percent
less than the baseline lifecycle greenhouse gas emissions.
Who Is Producing Cellulosic Biofuel Today?
Selected International Biorefinery Projects
The following projects represent a range of technologies and processes being deployed throughout the world, all defined as cellulosic biofuels.
|Company||Plant Location||Feedstock||Technology||Capacity (gallons/year)|
|Abengoa||Hugoton, Kan.||corn stover, wheat straw, milo (sorghum) stubble, switchgrass, and others||thermochemical and biochemical processing||11.4 million|
|Abengoa||York, Neb.||corn stover, residual starch||enzymatic hydrolysis (Chrysosporium lucknowense), integrated with dry mill corn production||0.47 million (0.02 million from corn stover)|
|Abengoa||Salamanca, Spain||wheat straw, cereal||steam pretreatment, enzymatic hydrolysis||1.3 million|
|BioEthanol Japan||Osaka, Japan||wood construction waste||enzymatic hydrolysis, fermentation (Klebsiella oxytoca and E. coli)||0.37 million|
|BlueFire Ethanol||Lancaster, Calif.||green waste||acid hydrolysis, fermentation||3.1 million|
|China Resources Alcohol Corporation||ZhaoDong City, Heilongjiang Province||corn stover||steam pretreatment, enzymatic hydrolysis||1.7 million|
|Iogen||Ottawa, Canada||wheat, oat and barley straw||enzymatic hydrolysis (Trichoderma reesei, Saccharomyces||0.79 million|
|KL Process Design||Upton, Wyo.||Ponderosa pine wood chips, waste||CO2 pretreatment, enzymatic hydrolysis||1 million|
|Lignol||Vancouver, Canada||softwood and hardwood||pulping liquor pretreatment, enzymatic hydrolysis||1.3 million|
|Mascoma||Lansing, Mich.||wood, forestry residues||enzymatic hydrolysis and fermentation (Thermoanaero-bacterium saccharolyticum)||40 million|
|Poet||Emmetsburg, Iowa||corn fiber, corn stover||enzymatic hydrolysis, integrated with dry mill||30 million|
|Range Fuels||Soperton, Ga.||timber and forest residue||pyrolysis and catalytic conversion||40 million|
|Verenium||Jennings, La.||sugarcane bagasse and specially bred energy cane||enzymatic hydrolysis, fermentation (Klebsiella oxytoca and E. coli)||1.4 million|
|Vivergo (BP, British Sugar, Dupont)||Saltend, Hull, England||wheat not suitable for human consumption||enzymatic hydrolysis, fermentation||110 million|