Biofuel in the United States
|This article is outdated. (November 2013)|
The United States produces mainly biodiesel and ethanol fuel, which uses corn as the main feedstock. Since 2005 the US overtook Brazil as the world's largest ethanol producer. In 2006 the US produced 4.855 billion US gallons (18.38×106 m3) of ethanol. The United States, together with Brazil accounted for 70 percent of all ethanol production, with total world production of 13.5 billion US gallons (51×106 m3) (40 million metric tons). When accounting just for fuel ethanol production in 2007, the U.S. and Brazil are responsible for 88% of the 13.1 billion US gallons (50×106 m3) total world production. Biodiesel is commercially available in most oilseed-producing states. As of 2005[update], it was somewhat more expensive than fossil diesel, though it is still commonly produced in relatively small quantities (in comparison to petroleum products and ethanol fuel). Due to increasing pollution control and climate change requirements and tax relief, the U.S. market is expected to grow to 1 to 2 billion US gallons (3.8×106 to 7.6×106 m3) by 2010.
Biofuels are mainly used mixed with fossil fuels. They are also used as additives. The largest biodiesel consumer is the U.S. Army. Most light vehicles on the road today in the US can run on blends of up to 10% ethanol, and motor vehicle manufacturers already produce vehicles designed to run on much higher ethanol blends. The demand for bioethanol fuel in the United States was stimulated by the discovery in the late 90s that methyl tertiary butyl ether (MTBE), an oxygenate additive in gasoline, was contaminating groundwater. Cellulosic biofuels are under development, to avoid upward pressure on food prices and land use changes that would be expected to result from a major increase in use of food biofuels.
Biofuels are not just limited to liquid fuels. One of the often overlooked uses of biomass in the United States is in the gasification of biomass. There is a small, but growing number of people using woodgas to fuel cars and trucks all across America.
The challenge is to expand the market for biofuels beyond the farm states where they have been most popular to date. Flex-fuel vehicles are assisting in this transition because they allow drivers to choose different fuels based on price and availability.
It should also be noted that the growing ethanol and biodiesel industries are providing jobs in plant construction, operations, and maintenance, mostly in rural communities. According to the Renewable Fuels Association, the ethanol industry created almost 154,000 U.S. jobs in 2005 alone, boosting household income by $5.7 billion. It also contributed about $3.5 billion in tax revenues at the local, state, and federal levels. On the other hand, in 2010, the industry received $6.646 billion in federal support (not counting state and local support).
Based upon average U.S. corn yields for the years 2007 through 2012, conversion of the entire US corn crop would yield 34.4 billion gallons of ethanol which is approximately 25% of 2012 finished motor fuel demand.
- 1 History
- 2 Legislation
- 3 Ethanol fuel
- 4 Biodiesel
- 5 Methanol fuel
- 6 Butanol Fuel
- 7 By state
- 8 United States Department of Energy projects
- 9 Biofuel companies
- 10 See also
- 11 References
- 12 External links
|This section requires expansion. (August 2012)|
The United States used biofuel in the beginning of the 20th century. For example, models of Ford T ran with ethanol fuel. Then the interest in biofuels declined until the first and second oil crisis (1973 and 1979).
The Department of Energy established the National Renewable Energy Laboratory in 1974 and started to work in 1977. The NREL publish papers on biofuels. Congress also voted the Energy Policy Act in 1994 and a newer in 2005 to promote renewable fuels.
Renewable Fuel Standard (RFS1)
The current National Renewable Fuel Standard program (RFS1) was established under the Energy Policy Act of 2005, which amended the Clean Air Act by establishing the first national renewable fuel standard. The U.S. Congress gave the U.S. Environmental Protection Agency (EPA) the responsibility to coordinate with the U.S. Department of Energy, the U.S. Department of Agriculture, and stakeholders to design and implement this new program.
The Renewable Fuel Standard called for 7.5 billion US gallons (28×106 m3) of biofuels to be used annually by 2012, expanding the market for biofuels.
The EPA announced that the 2009 Renewable Fuel Standard will require most refiners, importers, and non-oxygenate blenders of gasoline to displace 10.21% of their gasoline with renewable fuels such as ethanol. That requirement aims to ensure that at least 11.1 billion US gallons (42×106 m3) of renewable fuels will be sold in 2009, in keeping with the targets established by the Energy Independence and Security Act of 2007 (EISA). While the RFS requirement is increasing by about 23%—from 9 billion US gallons (34×106 m3) in 2008 to 11.1 billion US gallons (42×106 m3) in 2009—the percentage requirement is increasing by nearly one third, from 7.76% in 2008 to 10.21% in 2009.
The EPA determines that fuel blenders are meeting renewable fuel requirements by examining Renewable Identification Numbers that they submit to the agency.
The 2009 RFS is also pushing up against what is known as the "blend wall". To address the blend wall issue, DOE and others are studying the use of mid-range blends, such as E15 and E20, for use in standard gasoline-burning vehicles. Allowing all gasoline blends to contain up to 20% ethanol would double the potential market for ethanol.
Renewable Fuel Standard (RFS2)
In May 2009, the EPA released proposed revisions to the National Renewable Fuel Standard program. These revisions addressed changes to the Renewable Fuel Standard program as required by EISA. The revised statutory requirements establish new specific volume standards for cellulosic biofuel, biomass-based diesel, advanced biofuel, and total renewable fuel that must be used in transportation fuel each year. The revised statutory requirements also include new definitions and criteria for both renewable fuels and the feedstocks used to produce them, including new greenhouse gas emission (GHG) thresholds for renewable fuels. The regulatory requirements for RFS will apply to domestic and foreign producers and importers of renewable fuel.
Of these modifications, several are significantly notable. First, the volume standard under RFS2 was increased beginning in 2008 from 5.4 to 9.0 billion US gallons (20,000,000 to 34,000,000 m3). Thereafter, the required volume continues to increase under RFS2, eventually reaching 36 billion US gallons (140×106 m3) by 2022.
|Renewable Fuel Volume Requirements for RFS2|
|Year||Biomass-Based Diesel||Cellulosic Biofuel||Total Advanced Biofuel||Total Renewable Fuel|
|billion US gallons||million cubic meters||billion US gallons||million cubic meters||billion US gallons||million cubic meters||billion US gallons||million cubic meters|
Greenhouse gas reduction thresholds
EISA established new renewable fuel categories and eligibility requirements, including setting the first ever mandatory greenhouse gas reduction thresholds for the various categories of fuels. For each renewable fuel pathway, greenhouse gas emissions are evaluated over the full life cycle, including production and transport of the feedstock; land use change; production, distribution, and blending of the renewable fuel; and end use of the renewable fuel. The GHG emissions are then compared to the life cycle emissions of 2005 petroleum baseline fuels (base year established as 2005 by EISA) displaced by the renewable fuel, such as gasoline or diesel. The life cycle GHG emissions performance reduction thresholds as established by EISA range from 20 to 60 percent reduction depending on the renewable fuel category.
|Lifecycle GHG Thresholds Specified in EISA (percent reduction from 2005 baseline)|
The demand for ethanol fuel in the United States was stimulated by the discovery in the late 1990s that methyl tertiary butyl ether (MTBE), an oxygenate additive in gasoline, was contaminating groundwater. Due to the risks of widespread and costly litigation, and because MTBE use in gasoline was banned in almost 20 states by 2006, the substitution of MTBE opened a new market for ethanol fuel. This demand shift for ethanol as an oxygenate additive took place at a time when oil prices were already significantly rising. This shift also contributed to an expansion in the use of gasohol E10 and to a sharp increase in the production and sale of E85 flex vehicles since 2002.
| United States (1)
States with mandatory use of
|Notes: (1) Florida effective in 2010.|
Low ethanol blends
Most cars on the road today in the U.S. can run on blends of up to 10% ethanol (E10), and motor vehicle manufacturers already produce vehicles designed to run on much higher ethanol blends. Though E10 is mandatory only in 10 states, ethanol blends in the US are available in other states as optional or added on lower percentages as a subsititute to MTBE (used to oxygenate gasoline) without any labeling, making E blends present in two-thirds of the US gas supply.
Ford, DaimlerChrysler, and GM are among the automobile companies that sell "flexible-fuel" cars, trucks, and minivans that can use gasoline and ethanol blends ranging from pure gasoline up to 85% ethanol (E85). By mid-2008, there were approximately seven million E85-compatible vehicles on U.S. roads. However, a 2005 survey found that 68% of American flex-fuel car owners were not aware they owned an E85 flex. This is due to the fact that the exterior of flex and non-flex vehicles look exactly the same; there is no sale price difference between them; the lack of consumer's awareness about E85s; and also the decision of American automakers of not putting any kind of exterior labeling, so buyers can be aware they are getting an E85 vehicle. Since 2006 many new FFV models in the US feature a bright yellow gas cap to remind drivers of the E85 capabilities, and GM is also using badging with the text "Flexfuel/E85 Ethanol" to clearly mark the car as an E85 FFV.
A major restriction hampering sales of E85 flex vehicles or fuelling with E85, is the limited infrastructure available to sell E85 to the public, as by October 2008 there were only 1,802 gasoline filling stations selling E85 to the public in the entire US, with a great concentration of E85 stations in the Corn Belt states, led by Minnesota with 357 stations, more than any other state, followed by Illinois with 189, Wisconsin with 118, and Missouri with 112. Only seven states do not have E85 available to the public, Alaska, Hawaii, Maine, New Hampshire, New Jersey, Rhode Island, and Vermont. The main constraint for a more rapid expansion of E85 availability is that it requires dedicated storage tanks at filling stations, at an estimated cost of USD 60,000 for each dedicated ethanol tank.
Chrysler, General Motors, and Ford have each pledged to manufacture 50 percent of their entire vehicle line as flexible fuel in model year 2012, if enough fueling infrastructure develops. Regarding energy policy, President-elect Barack Obama pledged during his electoral campaign to significantly reduce oil consumption, with measures that among others include mandating all new vehicles to have FFV capability by the end of 2013.
GreenHunter Energy, Inc. has begun commercial operations at its biodiesel refinery in Houston, Texas, that can produce 105 million US gallons per year (400×103 m3/a) of biodiesel. That production capacity makes it the largest biodiesel refinery in the United States, barely beating out the 100 million US gallons per year (380×103 m3/a) biodiesel refinery built by Imperium Renewables in Washington.
For comparison, the total U.S. production capacity for biodiesel reached 2,240 million US gallons per year (8.5×106 m3/a) in 2007, although poor market conditions held 2007 production to about 450 million US gallons (1.7×106 m3), according to the National Biodiesel Board (NBB).
In 2006, Fuel Bio Opened the largest biodiesel manufacturing plant on the east coast of the United States in Elizabeth, New Jersey. Fuel Bio's operation is capable of producing a name plate capacity of 50 million US gallons (190×103 m3) of biodiesel per year.
Methanol was first produced from pyrolysis of wood, resulting in its common English name of wood alcohol. Presently, methanol is usually produced using methane (the chief constituent of natural gas) as a raw material. It may also be produced by pyrolysis of many organic materials or by Fischer Tropsch from synthetic gas, so be called biomethanol. Production of methanol from synthesis gas using Biomass-To-Liquid can offer methanol production from biomass at efficiencies up to 75%. Widespread production by this route has a postulated potential (see Olah reference above) to offer methanol fuel at a low cost and with benefits to the environment. These production methods, however, are not suitable for small scale production.
Successful test programs in Europe and the US, mainly in California, were conducted with methanol flex-fuel vehicles, known as M85 flex-fuel vehicles. Ford began development of a flexible-fuel vehicle in 1982, and between 1985 and 1992, 705 experimental FFVs were built and delivered to California and Canada, including the 1.6L Ford Escort, the 3.0L Taurus, and the 5.0L LTD Crown Victoria. These vehicles could operate on either gasoline or methanol with only one fuel system. Legislation was passed to encourage the US auto industry to begin production, which started in 1993 for the M85 FFVs at Ford. In 1996, a new FFV Ford Taurus was developed, with models fully capable of running on either methanol or ethanol blended with gasoline. This ethanol version of the Taurus became the first commercial production of an E85 FFV. The momentum of the FFV production programs at the American car companies continued, although by the end of the 1990s, the emphasis shifted to the E85 version, as it is today. Ethanol was preferred over methanol because there is a large support from the farming community, and thanks to the government's incentive programs and corn-based ethanol subsidies.
In 2005, California's Governor, Arnold Schwarzenegger, terminated the use of methanol after 25 years and 200 million miles of successful operation, to join the expanding use of ethanol driven by producers of corn. In spite of this, he was optimistic about the future of the program, claiming "it will be back." Ethanol is currently (as of 2009) priced at 2 to 3 dollars per gallon, while methanol made from natural gas remains at 47 cents per gallon. Presently there are over 60 operating gas stations in California supplying methanol in their pumps.
A team of chemical engineers at the University of Arkansas have developed a method for converting common algae into butanol, which can be used as fuel in existing gasoline internal combustible engines. The algae are grown on "raceway" troughs and the algaes growth is enhanced by delivering high concentrations of carbon dioxide through hollow fiber membranes.
Questions have been raised about the amount of energy needed to produce fuel-grade ethanol compared to the amount of energy it releases upon combustion. Depending on who you ask, you may get a different answer as to whether or not ethanol from corn produces more energy than it consumes.
Therefore, companies like BP and DuPont have been looking at the next generation of biofuel, specifically investigating butanol.
Specific advantages to using butanol compared to ethanol include, higher energy content per kg, the ability to be blended at higher concentrations without further adaptation of vehicles, and potential to use existing storage/transport infrastructure.
However, using corn as a feedstock to produce either ethanol or butanol seems infeasible without significant technology improvements regarding yields. Currently, about 2.5 US gallons (9.5 L) of butanol can be produced per bushel of corn (373 l/t). Meanwhile, about 2.75 US gallons (10.4 L) of ethanol can be produced per bushel of corn (410 l/t). Our current production of ethanol is about 5 billion US gallons per year (19×106 m3/a), but it requires 20% of the United States' corn crop and only replaces 1% of its petroleum use. Reaching the 36 billion US gallons (140×106 m3) biofuel mandate by 2022, would be a difficult task if only using a corn grain feedstock.
Louisiana State University Agricultural Center researchers in the Louisiana Institute for Biofuels and Bioprocessing are studying the regular production of biomass for economically viable conversion to biofuels and bioenergy using existing refinery infrastructure. This project, called the LSU AgCenter Sustainable Bioproducts Initiative, involves a team of university and industry partners who are studying how to use energy cane and sweet sorghum to help reinvigorate the Louisiana sugar and chemical industries. The project will expand the United States’ southern regional agricultural sector by utilizing sweet sorghum and energy cane to produce butanol, gasoline, isoprene and byproduct chemicals. Developers believe the project eventually will contribute significantly to improving rural prosperity and job creation in the southern region of the United States.
Michigan State University researcher Bruce Dale says that 30% of USA's energy can be achieved by 2030. The greenhouse emissions are reduced by 86% for cellulose compared to corn's 29% reduction. A plant is being built now in Georgia to make up to 100 million US gallons (380,000 m3) per year.
Minnesota Governor Tim Pawlenty signed a bill on May 12, 2008, that will require all diesel fuel sold in the state for use in internal combustion engines to contain at least 20% biodiesel by May 1, 2015.
Oregon Governor Ted Kulongoski signed legislation in July 2007 that will require all gasoline sold in the state to be blended with 10% bioethanol (a blend known as BE10) and all diesel fuel sold in the state to be blended with 2% biodiesel (a blend known as BD2).
Oregon currently has the only biofuels station in the country that can be used by any type of vehicle.
United States Department of Energy projects
The United States Department of Energy has announced that it has selected six university-led advanced biofuels projects to receive up to $4.4 million, subject to annual appropriations. The awardees—Georgia Tech Research Corporation, the University of Georgia, the University of Maine, Montana State University, Steven's Institute of Technology in New Jersey, and the University of Toledo in Ohio—will all receive funding to conduct research and development of cost-effective, environmentally friendly biomass conversion technologies for turning non-food feedstocks into advanced biofuels. Combined with a university cost share of 20%, more than $5.7 million is slated for investment in these projects.
Most of the projects will involve microbiology, including the University of Georgia and Montana State University projects, which are both focused on producing oils from algae. The University of Georgia will investigate the use of poultry litter to produce low-cost nutrients for algae, while Montana State, in partnership with Utah State University, will research the oil content, growth, and oil production of algae cultures in open ponds. Applying microbiology to biomass conversion, the University of Maine will study the use of bacteria to create biofuels from regionally available feedstocks, such as seaweed sludge and paper mill waste streams, while the University of Toledo will attempt to use pellets containing enzymes to efficiently convert cellulosic biomass into ethanol.
In contrast, Georgia Tech Research Corporation and Steven's Institute of Technology are both investigating the gasification of biomass. Georgia Tech will evaluate two experimental gasifiers run on forest residues, while Steven's Institute will test a novel microchannel reactor reactor that gasifies pyrolysis oil, a petroleum-like oil produced by exposing biomass sources such as wood chips to high temperatures in the absence of oxygen. Gasified biomass can be used as a gaseous fuel or passed through a catalyst to produce a wide range of liquid fuels and chemicals.
Unfortunately, costs of producing ethanol from cellulosic feedstock such as wood chips are still about 70% higher than production from corn, because of an extra step in the production process, when compared to production of corn-derived ethanol. Until recently, the idea of extracting ethanol from farm waste and other sources was barely clinging to life in the recesses of university campuses and federal labs, because production problems, as well as the need to bring together a vast team of specialists. Consider: Finding a bacterium from a cow's intestinal tract or from elephant dung that has the correct enzyme to degrade cellulose, and then bringing in geneticists to modify that enzyme kept this discouraging feat from ever growing beyond its embryonic state. Now, that is all changing with a race by approximately thirty companies attempting to accomplish this alchemical feat, and in the process working directly or coordinating with: environmental groups, biotechnology firms, some major oil companies, chemical giants, auto makers, defense hawks, and venture capitalists. The winner will be whoever can make cellulosic ethanol in mass quantities for as little money per gallon as possible.
With the majority of such biofuel companies (Iogen Corporation, SunOpta's BioProcess Group, Genencor, Novozymes, Dyadic International, Inc. (DYAI), Kansas City-based Alternative Energy Sources, Inc. [Nasdaq:AENS], Flex Fuels USA based in Huntsville, Alabama (now owned by Alternative Energy Sources), or BRI Energy, LLC, Abengoa Bioenergy) located in North America, the United States is in a unique position to lead the way in the development, production, and sale of a new source of energy.
One notable company that deserves special mention is Archer-Daniels-Midland Company (ADM) which has already invested heavily into building approximately 100 corn-ethanol production plants, known as bio-refineries, and churns out about one-fifth of the country's ethanol supply. This occurred due to seasonal overcapacity in its corn syrup plants when surplus was available to produce ethanol. Moreover, ADM is in a unique position to utilize unused parts of the corn crop, and convert previously discarded waste into a viable product. The hull surrounding corn contains fiber that the Decatur, Illinois, grain-processing giant's ethanol-making microorganisms can not use. Figuring out how to convert the fiber into more sugar could increase the output of an existing corn-ethanol plant by 15%. Consequently, ADM wouldn't have to figure out how to collect a new source of biomass but merely use the existing infrastructure for gathering corn—resulting in an advantage over its competitors. ADM executives want government help to build a plant that could cost between $50 million and $100 million. Prescient in their position in the quest for success, ADM recently hired the head of petroleum refining at Chevron, Patricia A. Woertz, to metamorphasize ADM into the Exxon-Mobil of the ethanol industry. If ADM succeeds, it will catapult beyond the ethanol industry to compete with the larger, global energy industry. In essence, the old paradigm of processing a barrel of crude oil into gasoline will be replaced with processing a bushel of corn into ethanol.
Meanwhile DuPont, the chemical giant, is attempting to figure out how to construct a bio-refinery fueled by corn stover—the stalk and leaves that are left in the field after farmers harvest their crop. The company's goal is to make ethanol from cellulose as cheaply as from corn kernels by 2009. If it works, the technology could double the amount of ethanol produced by a field of corn.
Diversa Corporation, a biotech company based in San Diego, examined how biomass is converted into energy in the natural environment. They have found that the enzymes inherent in the bacteria and protozoa that inhabit the digestive tracts of the household termite efficiently convert 95% of cellulose into fermentable sugars. Using proprietary DNA extraction and cloning technologies, they were able to isolate the cellulose-degrading enzymes. By reenacting this natural process, the company created a cocktail of high-performance enzymes for industrial ethanol production enablers. Although still in the early stages of this work, the initial results are promising. Currently, these expensive enzymes cost about 25 cents per gallon of ethanol, although this price is very likely to decline by half in the coming years.
Construction of the first U.S. commercial plant producing cellulosic ethanol will commence in the State of Iowa in February 2007. The Voyager Ethanol plant in Emmetsburg, owned by POET, LLC, will be converted from a 50-million-US-gallon-per-year (190×103 m3/a) conventional corn dry mill facility into a 125-million-US-gallon-per-year (470×103 m3/a) commercial-scale biorefinery producing ethanol from not only corn but also the stalk, leaves, and cobs of the corn plant.
Most ethanol plants rely on natural gas to power their processing equipment. The process to be used at the Emmetsburg plant will enable the plant to make 11% more ethanol by weight of corn and 27% more by area of corn. The process cuts the need for fossil fuel power at the plant by 83% by using some of its own byproduct for power. The $200 million plant is scheduled to begin in February and take about 30 months to complete. Project completion is contingent upon partial funding from a USDOE grant, which is likely as the U.S. Government views the renewable energy project as a full-blown national security issue.
- Energy policy of the United States
- Ethanol fuel in the United States
- E85 in the United States
- Greenhouse gas emissions by the United States
- Renewable energy commercialization in the United States
- Biofuels by region
- List of renewable energy topics by country
- Renewable Fuel Standard
- [dead link]
- "Industry Statistics: Annual World Ethanol Production by Country". Renewable Fuels Association. Archived from the original on April 8, 2008. Retrieved 2008-05-02.
- Goettemoeller, Jeffrey; Adrian Goettemoeller (2007). "Sustainable Ethanol: Biofuels, Biorefineries, Cellulosic Biomass, Flex-Fuel Vehicles, and Sustainable Farming for Energy Independence". Prairie Oak Publishing, Maryville, Missouri. pp. 56–61. ISBN 978-0-9786293-0-4.
- "Eliminating MTBE in Gasoline in 2006" (PDF). Environmental Information Administration. 2006-02-22. Retrieved 2008-08-10.
- "Woodgas used as alternative energy to fuel cars and truck". Woodgas.net. Retrieved 2010-07-15.
- "The craze for maize", The Economist, May 12, 2007, pp.33-34
- Worldwatch Institute and Center for American Progress (2006). American energy: The renewable path to energy security
- "Direct Federal Financial Interventions and Subsidies in Energy in Fiscal Year 2010". Energy Information Administration. August 1, 2011. Retrieved April 29, 2012.
- "NASS - Charts and Maps - Field Crops". Nass.usda.gov. 2005-12-05. Retrieved 2014-02-22.
- "U.S. Product Supplied for Crude Oil and Petroleum Products". Eia.gov. Retrieved 2014-02-22.
- [dead link]
- "American energy: The renewable path to energy security". Worldwatch Institute and Center for American Progress. 2006. Retrieved 2014-02-22.
- "EERE News: EPA Sets Renewable Fuel Requirement of 10.21% for 2009". Apps1.eere.energy.gov. 2008-11-19. Retrieved 2010-07-15.
- "The new specific volume standards for cellulosic biofuel, biomass-based diesel, advanced biofuel, and total renewable fuel by year". Epa.gov. Retrieved 2014-02-22.
- "Changing the Climate: Ethanol Industry Outlook 2008" (PDF). Renewable Fuels Association. Archived from the original on 2008-05-28. Retrieved 2008-05-10. Source:F.O. Licht
- National Renewable Energy Laboratory USDoE (2007-09-17). "Data, Analysis and Trends: Light Duty E85 FFVs in Use (1998-2008)". Alternative Fuels and Advanced Vehicles Data Center. Retrieved 2008-08-28. Trend of total FFVs in use from 1998-2008, based on FFV production rates and life expectancy (Excel file)
- "State Legislation". Ethanol.org. Retrieved 2008-10-24. Florida starting in 2010 and Minnesota will go up to E20 in 2013.
- Kate Galbraith (2008-07-26). "In Gas-Powered World, Ethanol Stirs Complaints". The New York Times. Retrieved 2008-10-24.
- Inslee, Jay; Bracken Hendricks (2007). "Apollo's Fire". Island Press, Washington, D.C. pp. 153–155, 160–161. ISBN 978-1-59726-175-3. See Chapter 6. Homegrown Energy.
- Ken Thomas (2007-05-07). "'Flex-fuel' vehicles touted". USA Today. Retrieved 2008-09-15.
- Christine Gable and Scott Gable. "Yellow E85 gas cap". About.com: Hybrid Cars & Alt Fuels. Retrieved 2008-09-18.
- John Neff (2006-10-06). "More gas cap news: Chrysler going yellow for E85". AutoBlog. Retrieved 2008-10-08.
- Sam Abuelsamid (2007-03-28). "AFVI: Ford confirms that all 2008 police interceptors will be flex-fuel". AutobogGreen. Retrieved 2008-10-08.
- Christine Gable and Scott Gable. "2008 Chevrolet Silverado 1500 4WD LT2 flex-fuel truck test drive". About.com: Hybrid Cars & Alt Fuels. Retrieved 2008-10-03.
- Christine Gable and Scott Gable. "2007 Chevrolet Suburban 4WD 1500 LT test drive". About.com: Hybrid Cars & Alt Fuels. Retrieved 2008-10-03.
- Michelle Kautz (2008-10-13). "E85 Stations Exceed 1,800". National Ethanol Vehicle Coalition. Retrieved 2008-10-22.
- NEVC. "E85 Refueling Location Search". National Ethanol Vehicle Coalition. Retrieved 2008-10-22. Number of stations in leading states complemented with search on http://www.e85refueling.com
- Glen Hess (2007-09-17). "Renewable Fuels Face Bumpy Road". Chemical & Engineering News. Retrieved 2008-08-19. pp. 28-30
- "Letter to Nancy Pelosi, Speaker of the United States House of Representatives". e85fuel. 2008-09-09. Retrieved 2008-10-09.
- "GM to launch 18 flexible fuel vehicles including Hummer, Chevrolet and Caddy models". Live Wire Edition. 2008-08-22. Retrieved 2008-10-09.
- "Barack Obama and Joe Biden: New Energy for America" (PDF). Barack Obama campaign site. 2008-08-03. Retrieved 2008-11-05.
- [dead link]
- "It's Clean, Green and from a bean". New Jersey, Star Ledger. Retrieved 2014-02-22.
- Roberta J Nichols (2003). "The Methanol Story: A Sustainable Fuel for the Future" (PDF). Methanol Institute. Retrieved 2008-08-30. Also published in the Journal of Scientific & Industrial Research Vol. 62, January–February 2003, pp. 97-105
- Ryan, Lisa; Turton, Hal (2007). "Sustainable Automobile Transport". Edward Elgar Publishing Ltd, England. pp. 40–41. ISBN 978-1-84720-451-6.
- Green Car Journal Editors (1994). "Cars On Alcohol, Part 9: Corn Based Ethanol in the US". Green Car. Retrieved 2008-08-31.
- Paul Dever (January 1996). "Alternative Fuel Ford Taurus". The Auto Channel. Retrieved 2008-08-14. Original source: 1996 North American International Auto Show Press Release
- Green Car Journal Editors (1995). "Cars On Alcohol, Part 13: GM Supports FlexFuel". Green Car. Retrieved 2008-08-31.
- "Algae converted to butanol; Fuel can be used in automobiles". ScienceDaily. Retrieved 2014-02-22.
- "Chemical & Engineering News - Cover Story: Point/Counterpoint - The Costs Of Biofuels". Pubs.acs.org. Retrieved 2010-07-15.
- [dead link]
- [dead link]
- "Butanol : An Energy Alternative?". Ethanol.org. Retrieved 2014-02-22.
- "Illinois Corn". Ilcorn.org. Retrieved 2010-07-15.
- "U.S. Won't Meet Its Own Biofuel Mandate : Greentech Media". Greentechmedia.com. 2008-12-17. Retrieved 2010-07-15.
- "SUBI - Sustainable Bioproducts Initiative". Lsuagcenter.com. 2014-02-04. Retrieved 2014-02-22.
- AgCenter, LSU. "SUBI".
- [dead link]
- "EERE News: Minnesota to Require 20% Biodiesel Blends by 2015, with Caveats". Eere.energy.gov. Retrieved 2010-07-15.
- "Relating to fuel; creating new provisions; amending ORS 215". Leg.state.or.us. Retrieved 2010-07-15.
- [dead link]
- "is the world leader in bioinnovation". Novozymes. Retrieved 2010-07-15.
- "Alternative Energy agrees to buy Alabama company - Kansas City Business Journal:". Bizjournals.com. 2006-08-11. Retrieved 2010-07-15.
- Sustainable Energy Resources. "Clean Technology for Renewable Energy". BRI Energy. Retrieved 2010-07-15.
- "Abengoa Bioenergy". Abengoa Bioenergy. Retrieved 2010-07-15.
- "A Bet on Ethanol, With a Convert at the Helm"; New York Times, October 8, 2006, p. 9.
- "A Bet on Ethanol, With a Convert at the Helm"; New York Times, October 8, 2006, p.1.
- "Nebraska ethanol company to acquire plant in Minn.". Chicago Tribune. February 18, 2011. Retrieved February 15, 2012.
||This article's use of external links may not follow Wikipedia's policies or guidelines. (February 2014)|
- How much biofuel does the United States consume?
- Alternative Fueling Station Locator (EERE).
- Cellulosic biofuels
- Presentations on biofuel sponsored by The Center for Global Studies, University of Illinois at Urbana-Champaign