Ethanol fuel

Ethanol fuel

Ethanol fuel is ethanol (ethyl alcohol), the same type of alcohol found in alcoholic beverages. It can be used as a fuel, mainly as a biofuel alternative to gasoline, and is widely used in cars in Brazil. Because it is easy to manufacture and process and can be made from very common crops such as sugar cane and corn, it is an increasingly common alternative to gasoline in some parts of the world.

Anhydrous ethanol (ethanol with less than 1% water) can be blended with gasoline in varying quantities up to pure ethanol (E100), and most spark-ignited gasoline style engines will operate well with mixtures of 10% ethanol (E10). [ [ What is Bioethanol] ] Most cars on the road today in the U.S. can run on blends of up to 10% ethanol, [Worldwatch Institute and Center for American Progress (2006). [ "American energy: The renewable path to energy security"] ] and the use of 10% ethanol gasoline is mandated in some cities where harmful levels of auto emissions are possible. [ [ EIA- 819 Monthly Oxygenate Report] ]

Ethanol can be mass-produced by fermentation of sugar or by hydration of ethylene (ethene CH2=CH2) from petroleum and other sources. Current interest in ethanol mainly lies in bio-ethanol, produced from the starch or sugar in a wide variety of crops, but there has been considerable debate about how useful bio-ethanol will be in replacing fossil fuels in vehicles. Concerns relate to the large amount of arable land required for crops, [ [ Deforestation diesel – the madness of biofuel] ] as well as the energy and pollution balance of the whole cycle of ethanol production. [Youngquist, W. Geodestinies, National Book company, Portland, OR, 499p.] [ [ The dirty truth about biofuels] ] Recent developments with cellulosic ethanol production and commercialization may allay some of these concerns. [ [ Biofuels look to the next generation] ]

According to the International Energy Agency, cellulosic ethanol could allow ethanol fuels to play a much bigger role in the future than previously thought.International Energy Agency (2006). [ "World Energy Outlook 2006"] p. 8.] Cellulosic ethanol offers promise as resistant cellulose fibers, a major component in plant cells walls, can be used to generate ethanol. Dedicated energy crops such as switchgrass are also promising cellulose sources that can be produced in many regions of the United States.Biotechnology Industry Organization (2007). [ "Industrial Biotechnology Is Revolutionizing the Production of Ethanol Transportation Fuel"] pp. 3-4.]


Glucose (a simple sugar) is created in the plant by photosynthesis.

: 6CO2 + 6H2O + light → C6H12O6 + 6O2

During ethanol fermentation, glucose is decomposed into ethanol and carbon dioxide. :C6H12O6 → 2C2H6O + 2CO2 + heat

During combustion ethanol reacts with oxygen to produce carbon dioxide, water, and heat:

:C2H6O + 3O2 → 2CO2 + 3H2O + heat

After doubling the ethanol combustion reaction because two molecules of ethanol are produced for each glucose molecule, there are equal numbers of each type of molecule on each side of the equation, and the net reaction for the overall production and consumption of ethanol is just:

:light → heat

The heat of the combustion of ethanol is used to drive the piston in the engine by expanding heated gases. It can be said that sunlight is used to run the engine.

Air pollutants are also produced when ethanol is burned in the atmosphere rather than in pure oxygen. Harmful nitrous oxide gases are produced.


Ethanol is considered "renewable" because it is primarily the result of conversion of the sun's energy into usable energy. Creation of ethanol starts with photosynthesis causing the feedstocks such as switchgrass, sugar cane, or corn to grow. These feedstocks are processed into ethanol.

About 5% of the ethanol produced in the world in 2003 was actually a petroleum product. [ [ file g30819b40j] ] It is made by the catalytic hydration of ethylene with sulfuric acid as the catalyst. It can also be obtained via ethylene or acetylene, from calcium carbide, coal, oil gas, and other sources. Two million tons of petroleum-derived ethanol are produced annually. The principal suppliers are plants in the United States, Europe, and South Africa. [ [ (, Biofuels_study 268 kB pdf, footnote, p 6)] ] Petroleum derived ethanol (synthetic ethanol) is chemically identical to bio-ethanol and can be differentiated only by radiocarbon dating. [ [, article 2077] ]

Bio-ethanol is obtained from the conversion of carbon based feedstock. Agricultural feedstocks are considered renewable because they get energy from the sun using photosynthesis, provided that all minerals required for growth (such as nitrogen and phosphorus) are returned to the land. Ethanol can be produced from a variety of feedstocks such as sugar cane, bagasse, miscanthus, sugar beet, sorghum, grain sorghum, switchgrass, barley, hemp, kenaf, potatoes, sweet potatoes, cassava, sunflower, fruit, molasses, corn, stover, grain, wheat, straw, cotton, other biomass, as well as many types of cellulose waste and harvestings, whichever has the best well-to-wheel assessment.

Current, first generation processes for the production of ethanol from corn use only a small part of the corn plant: the corn kernels are taken from the corn plant and only the starch, which represents about 50% of the dry kernel mass, is transformed into ethanol. Two types of second generation processes are under development. The first type uses enzymes and yeast to convert the plant cellulose into ethanol while the second type uses pyrolysis to convert the whole plant to either a liquid bio-oil or a syngas. Second generation processes can also be used with plants such as grasses, wood or agricultural waste material such as straw.

Production process

The basic steps for large scale production of ethanol are: microbial (yeast) fermentation of sugars, distillation, dehydration (requirements vary, see Ethanol fuel mixtures, below), and denaturing (optional). Prior to fermentation, some crops require saccharification or hydrolysis of carbohydrates such as cellulose and starch into sugars. Saccharification of cellulose is called cellulolysis (see cellulosic ethanol). Enzymes are used to convert starch into sugar. [cite web
title= New Enzyme for More Efficient Corn Ethanol Production
date= 2005-06-30 |publisher= Green Car Congress
accessdate= 2008-01-14


Ethanol is produced by microbial fermentation of the sugar. Microbial fermentation will currently only work directly with sugars. Two major components of plants, starch and cellulose, are both made up of sugars, and can in principle be converted to sugars for fermentation. Currently, only the sugar (e.g. sugar cane) and starch (e.g. corn) portions can be economically converted. However, there is much activity in the area of cellulosic ethanol, where the cellulose part of a plant is broken down to sugars and subsequently converted to ethanol.


For the ethanol to be usable as a fuel, water must be removed. Most of the water is removed by distillation, but the purity is limited to 95-96% due to the formation of a low-boiling water-ethanol azeotrope. The 95.6% m/m (96.5% v/v) ethanol, 4.4% m/m (3.5% v/v) water mixture may be used as a fuel alone, but unlike anhydrous ethanol, is immiscible in gasoline, so the water fraction is typically removed in further treatment in order to burn with in combination with gasoline in gasoline engines.


There are basically five dehydration processes to remove the water from an azeotropic ethanol/water mixture. The first process, used in many early fuel ethanol plants, is called azeotropic distillation and consists of adding benzene or cyclohexane to the mixture. When these components are added to the mixture, it forms an heterogeneous azeotropic mixture in vapor-liquid-liquid equilibrium, which when distillated produces anhydrous ethanol in the column bottom, and a vapor mixture of water and cyclohexane/benzene. When condensed, this becomes a two-phase liquid mixture. Another early method, called extractive distillation, consists of adding a ternary component which will increase ethanol relative volatility. When the ternary mixture is distillated, it will produce anhydrous ethanol on the top stream of the column.

With increasing attention being paid to saving energy, many methods have been proposed that avoid distillation all together for dehydration. Of these methods, a third method has emerged and has been adopted by the majority of modern ethanol plants. This new process uses molecular sieves to remove water from fuel ethanol. In this process, ethanol vapor under pressure passes through a bed of molecular sieve beads. The bead's pores are sized to allow absorption of water while excluding ethanol. After a period of time, the bed is regenerated under vacuum to remove the absorbed water. Two beds are used so that one is available to absorb water while the other is being regenerated. This dehydration technology can account for energy saving of 3,000 btus/gallon compared to earlier azeotropic distillation. [ Modern Corn Ethanol plant description]


Ethanol-based engines

Ethanol is most commonly used to power automobiles, though it may be used to power other vehicles, such as farm tractors and airplanes. Ethanol (E100) consumption in an engine is approximately 51% higher than for gasoline since the energy per unit volume of ethanol is 34% lower than for gasoline. However, the higher compression ratios in an ethanol-only engine allow for increased power output and better fuel economy than could be obtained with lower compression ratios. [, course, October 22 v2] ] [ [ Efficiency Improvements Associated with Ethanol-Fueled Spark-Ignition Engines] ] In general, ethanol-only engines are tuned to give slightly better power and torque output to gasoline-powered engines. In flexible fuel vehicles, the lower compression ratio requires tunings that give the same output when using either gasoline or hydrated ethanol. For maximum use of ethanol's benefits, a much higher compression ratio should be used, [cite web
title= "MIT's pint-sized car engine promises high efficiency, low cost"
author= Nancy Stauffer | date= 2006-10-25 |work=
publisher= Massachusetts Institute of Technology
accessdate= 2008-01-14
] which would render that engine unsuitable for gasoline use. When ethanol fuel availability allows high-compression ethanol-only vehicles to be practical, the fuel efficiency of such engines should be equal or greater than current gasoline engines. However, since the energy content (by volume) of ethanol fuel is less than gasoline, a larger volume of ethanol fuel (151%) would still be required to produce the same amount of energy. [ [,com_joomblog/Itemid,0/joomblog_task,blog_view/joomblog_contentid,12019/ Squeezing More Out of Ethanol] ] In spite of that, as the ethanol-only vehicle wastes less energy, yielding the same or higher mileage.

A 2004 MIT study [ [ MIT Study] ] and an earlier paper published by the Society of Automotive Engineers [ [ SAE Paper 2001-01-2901] ] identify a method to exploit the characteristics of fuel ethanol substantially better than mixing it with gasoline. The method presents the possibility of leveraging the use of alcohol to even achieve definite improvement over the cost-effectiveness of hybrid electric. The improvement consists of using dual-fuel direct-injection of pure alcohol (or the azeotrope or E85) and gasoline, in any ratio up to 100% of either, in a turbocharged, high compression-ratio, small-displacement engine having performance similar to an engine having twice the displacement. Each fuel is carried separately, with a much smaller tank for alcohol. The high-compression (which increases efficiency) engine will run on ordinary gasoline under low-power cruise conditions. Alcohol is directly injected into the cylinders (and the gasoline injection simultaneously reduced) only when necessary to suppress ‘knock’ such as when significantly accelerating. Direct cylinder injection raises the already high octane rating of ethanol up to an effective 130. The calculated over-all reduction of gasoline use and CO2 emission is 30%. The consumer cost payback time shows a 4:1 improvement over turbo-diesel and a 5:1 improvement over hybrid. In addition, the problems of water absorption into pre-mixed gasoline (causing phase separation), supply issues of multiple mix ratios and cold-weather starting are avoided.

Ethanol's higher octane rating allows an increase of an engine's compression ratio for increased thermal efficiency. In one study, complex engine controls and increased exhaust gas recirculation allowed a compression ratio of 19.5 with fuels ranging from neat ethanol to E50. Thermal efficiency up to approximately that for a diesel was achieved. [cite web
title= Economical, High-Efficiency Engine Technologies for Alcohol Fuels
author= Matthew Brusstar | coauthors= Marco Bakenhus
date= |year= |month= |work=
format= PDF | publisher= U. S. Environmental Protection Agency
accessdate= 2008-01-14
] This would result in the MPG (miles per gallon) of a dedicated ethanol vehicle to be about the same as one burning gasoline.

Engine cold start during the winter

High ethanol blends present a problem to achieve enough vapor pressure for the fuel to evaporate and spark the ignition during cold weather. When vapor pressure is below 45 kPa starting a cold engine becomes difficult. [cite web | url= | title= Sustainable biofuels: prospects and challenges |author= |date= January 2008 |format= PDF |publisher= The Royal Society | accessdate= 2008-09-27 Policy document 01/08. See 4.3.1 Vapour pressure and bioethanol and Figure 4.3 for the relation between ethanol content and vapor pressure.] In order to avoid this problem at temperatures below 11 ° Celsius (59 °F), and to reduce ethanol higher emissions during cold weather, both the US and the European markets adopted E85 as the maximum blend to be used in their flexible fuel vehicles, and they are optimized to run at such blend. At places with harsh cold weather, the ethanol blend in the US has a seasonal reduction to E70 for these very cold regions, though it is still sold as E85.cite web | url= | title= When is E85 not 85 percent ethanol? When it’s E70 with an E85 sticker on it | author=Ethanol Promotion and Information Council| publisher= AutoblogGreen | date=2007-02-27 | accessdate=2008-08-24 |language= ] cite web|url= |title=Ethanol fuel and cars |publisher=Interesting Energy Facts|accessdate=2008-09-23|language=] At places where temperatures fall below -12 °C (10 °F) during the winter, it is recommended to install an engine heater system, both for gasoline and E85 vehicles. Sweden has a similar seasonal reduction, but the ethanol content in the blend is reduced to E75 during the winter months.cite web|url= |title=Swedish comments on Euro 5/6 comitology version 4, 30 May 2007: Cold Temperature Tests For Flex Fuel Vehicles |publisher=European Commission|author=Vägverket (Swedish Road Administration)| date=2007-05-30 |accessdate=2008-09-23|language=]

Brazilian flex fuel vehicles can operate with ethanol mixtures up to E100, which is hydrous ethanol (alcohol with up to 4% water), which causes vapor pressure to drop faster as compared to E85 vehicles, and as a result, Venezualen flex vehicles are built with a small secondary gasoline reservoir located near the engine to avoid starting problems in cold weather. The cold start with pure gasoline is particularly necessary for users of Brazil's southern and central regions, where temperatures normally drop below 15 ° Celsius (59 °F) during the winter. An improved flex motor generation that will be launched in 2009 will eliminate the need for this secondary gas storage tank.cite journal|url= |title=Here comes the 'Flex' vehicles third generation |journal=Revista Brasileira de BioEnergia|publisher=Centro Nacional de Referência em Biomassa (Cenbio) |date= August 2008|accessdate=2008-09-23|language=Portuguese Ano 2, No. 3 (every article is presented in both English and Portuguese)] cite news|url= |title=Bosch investe na segunda geração do motor flex |publisher=Gazeta do Povo|author=Agência Estado|date=2008-06-10|accessdate=2008-09-23|language=Portuguese]

Ethanol fuel mixtures

To avoid engine stall due to "slugs" of water in the fuel lines interrupting fuel flow, the fuel must exist as a single phase. The fraction of water that an ethanol-gasoline fuel can contain without phase separation increases with the percentage of ethanol. [This is shown for 25°C (77°F) in a gasoline-ethanol-water phase diagram, Fig 13 of cite web
title= Technical View on Biofuels for Transportation – Focus on Ethanol End-Use Aspects
author= Päivi Aakko |coauthors= Nils-Olof Nylund
date= |year= |month= |format= PDF |work= |publisher=
accessdate= 2008-01-14
] . This shows, for example, that E30 can have up to about 2% water. If there is more than about 71% ethanol, the remainder can be any proportion of water or gasoline and phase separation will not occur. However, the fuel mileage declines with increased water content. The increased solubility of water with higher ethanol content permits E30 and hydrated ethanol to be put in the same tank since any combination of them always results in a single phase. Somewhat less water is tolerated at lower temperatures. For E10 it is about 0.5% v/v at 70 F and decreases to about 0.23% v/v at -30 F. [as shown in Figure 1 of ]

In many countries cars are mandated to run on mixtures of ethanol. Brazil requires cars be suitable for a 25% ethanol blend, and has required various mixtures between 22% and 25% ethanol, since of July 2007 25% is required. The United States allows up to 10% blends, and some states require this (or a smaller amount) in all gasoline sold. Other countries have adopted their own requirements.Beginning with the model year 1999, an increasing number of vehicles in the world are manufactured with engines which can run on any fuel from 0% ethanol up to 100% ethanol without modification. Many cars and light trucks (a class containing minivans, SUVs and pickup trucks) are designed to be flexible-fuel vehicles (also called "dual-fuel" vehicles). In older model years, their engine systems contained alcohol sensors in the fuel and/or oxygen sensors in the exhaust that provide input to the engine control computer to adjust the fuel injection to achieve stochiometric (no residual fuel or free oxygen in the exhaust) air-to-fuel ratio for any fuel mix. In newer models, the alcohol sensors have been removed, with the computer using only oxygen and airflow sensor feedback to estimate alcohol content. The engine control computer can also adjust (advance) the ignition timing to achieve a higher output without pre-ignition when it predicts that higher alcohol percentages are present in the fuel being burned. This method is backed up by advanced knock sensors - used in most high performance gasoline engines regardless of whether they're designed to use ethanol or not - that detect pre-ignition and detonation.

Fuel economy

In theory, all fuel-driven vehicles have a fuel economy (measured as miles per US gallon, or liters per 100 km) that is directly proportional to the fuel's energy content. [ [ DOE FAQ] ] In reality, there are many other variables that come in to play that affect the performance of a particular fuel in a particular engine. Ethanol contains approx. 34% less energy per unit volume than gasoline, and therefore in theory, burning pure ethanol in a vehicle will result in a 34% reduction in miles per US gallon, given the same fuel economy, compared to burning pure gasoline. This assumes that the octane ratings of the fuels, and thus the engine's ability to extract energy from the fuels, are the [ site] ] [ Alternative Fuel Efficiencies in Miles per Gallon] ] For E10 (10% ethanol and 90% gasoline), the effect is small (~3%) when compared to conventional gasoline, [ [|RAA All About Cars - Ethanol in Petrol] February 2004. Royal Automobile Association of South Australia. Retrieved on 2007-04-29] and even smaller (1-2%) when compared to oxygenated and reformulated blends. [ [ EPA Info] ] However, for E85 (85% ethanol), the effect becomes significant. E85 will produce lower mileage than gasoline, and will require more frequent refueling. Actual performance may vary depending on the vehicle. Based on EPA tests for all 2006 E85 models, the average fuel economy for E85 vehicles resulted 25.56% lower than unleaded gasoline. The EPA-rated mileage of current USA flex-fuel vehicles [ [ EPA Mileage] ] should be considered when making price comparisons, but it must be noted that E85 is a high performance fuel, with an octane rating of about 104, and should be compared to premium. In one estimate the US retail price for E85 ethanol is 2.62 US dollar per gallon or 3.71 dollar corrected for energy equivalency compared to a gallon of gasoline priced at 3.03 dollar. Brazilian cane ethanol (100%) is priced at 3.88 dollar against 4.91 dollar for E25 (as July 2007).

Experience by country

The top five ethanol producers in 2006 were the United States with 4.855 billion U.S. liquid gallons (bg), Brazil (4.49 bg), China (1.02 bg), India (0.50 bg) and France (0.25 bg).cite web|url=|title=Industry Statistics: Annual World Ethanol Production by Country|publisher=Renewable Fuels Association|date= |accessdate=2008-05-02|language= ] Brazil and the United States accounted for 70 percent of all ethanol production, with total world production of 13.5 billion US gallons (40 million tonnes). When accounting just for fuel ethanol production in 2007, the U.S. and Brazil are responsible for 88% of the 13.1 billion gallons total world production. Strong incentives, coupled with other industry development initiatives, are giving rise to fledgling ethanol industries in countries such as Thailand, Colombia, and some Central American countries. Nevertheless, ethanol has yet to make a dent in world oil consumption of approximately 4000 million tonnes/yr (84 million barrels/day). [ [ It's a global thing] , "Ethanol Producer Magazine", August 2006.]

All countries in Central America, northern South America and the Caribbean are located in a tropical zone with suitable climate for growing sugar cane. In fact, most of these countries have a long tradition of growing sugar cane mainly for producing sugar and alcoholic beverages.

As a result of the guerilla movements in Central America, in 1983 the United States unilateral and temporarily approved the Caribbean Basin Initiative, allowing most countries in the region to benefit from several tariff and trade benefits. These benefits were made permanent in 1990 and more recently, these benefits were replaced by the Caribbean Basin Trade and Partnership Act, approved in 2000, and the Dominican Republic–Central America Free Trade Agreement that went to effect in 2008. All these agreements have allowed several countries in the region to export ethanol to the U.S free of tariffs. Until 2004, the countries that benefited the most were Jamaica and Costa Rica, but as the U.S. began demanding more fuel ethanol, the two countries increased their exports and two others began exporting. In 2007, Jamaica, El Salvador, Trinidad & Tobago and Costa Rica exported together to the U.S. a total of 230.5 million gallons of ethanol, representing 54.1% of U.S. fuel ethanol imports. Brasil began exporting ethanol to the U.S. in 2004 and exported 188.8 million gallons representing 44.3% of U.S. ethanol imports in 2007. The remaining imports that year came from Canada and China. In March 2007, "ethanol diplomacy" was the focus of President George W. Bush's Latin American tour, in which he and Brazil's president, Luiz Inacio Lula da Silva, were seeking to promote the production and use of sugar cane based ethanol throughout Latin America and the Caribbean. The two countries also agreed to share technology and set international standards for biofuels. The Brazilian sugar cane technology transfer would allow several Central American, Caribbean and Andean countries to take advantage of their tariff-free trade agreements to increase or become exporters to the United States in the short-term. [cite web |url= |title=U.S. and Brazil Seek to Promote Ethanol in West |publisher=The New York Times| author= Edmund L. Andrews and Larry Rother|date=2007-03-03 |accessdate=2008-04-28|language= ] Also, in August 2007, Brazil's President toured Mexico and several countries in Central America and the Caribbean to promote Brazilian ethanol technology. [cite web |url= |title=Diplomacia de biocombustibles" de Lula no genera entusiasmo |publisher=La Nación | author= Diana Renée |date=2007-08-10 |accessdate=2008-04-28|language=Spanish] The ethanol alliance between the U.S. and Brazil generated some negative reactions from Venezuela's President Hugo Chavez, [cite web |url= |title=Bush and Chávez Spar at Distance Over Latin Visit |publisher= The Washington Post | author= Jim Rutenberg and Larry Rohter|date=2007-03-10 |accessdate=2008-04-28|language= ] and by then Cuba's President, Fidel Castro, who wrote that "you will see how many people among the hungry masses of our planet will no longer consume corn"." "Or even worse"," he continued, "by offering financing to poor countries to produce ethanol from corn or any other kind of food, no tree will be left to defend humanity from climate change"."' [cite web |url= |title=Americas: Cuba: Castro Criticizes U.S. Biofuel Policies |publisher=The New York Times|author= |date=2007-03-30 |accessdate=2008-04-28|language= ] Daniel Ortega, Nicaragua's President, and one of the preferencial recipients of Brazilian technical aid also voiced critics to the Bush plan, but he vowed support for sugar cane based ethanol during Lula's visit to Nicaragua. [cite web |url= |title=Nicaragua president backs sugar-made biofuel as Lula visits |publisher=People's Daily Online |author=Xinhua News |date=2007-08-09 |accessdate=2008-04-28|language= ] [cite news |url= |title=Lula ofrece cooperación y energía eléctrica |publisher=La Nación |author=AFP |date=2007-08-09 |accessdate=2008-04-28|language=Spanish ]


Colombia's ethanol program began in 2002, based on a law approved in 2001 mandating a mix of 10% ethanol with regular gasoline, and the plan is to gradually reach a 25% blend in twenty-years. Sugar cane-based ethanol production began in 2005, when the law went into effect, and as local production was not enough to supply enough ethanol to the entire country's fleet, the program was implemented only on cities with more than 500,000 inhabitants, such as Cali, Pereira, and the capital city of Bogotá. All of the ethanol production comes from the Department of Valle del Cauca, Colombia's traditional sugar cane region. Cassava is the second source of ehtanaol, and potatoes and castor oil are also being studied. [cite web |url=|title=Energy-Colombia: Harvesting Sunshine for Biofuels |publisher=Inter Press Service News Agengy|author=Gloria Rey |date=2007-10-12 |accessdate=2008-07-30|language=]

Costa Rica

The government, based on the National Biofuel Program, established the mandatory use of all gasoline sold in Costa Rica with a blend of around 7.5% ethanol, starting in October 2008. The implementation phase follows a two year trial that took place in the provinces of Guanacaste and Puntarenas. The government expects to increase the percent of ethanol mixed with gasoline to 12% in the next 4 to 5 years. The Costa Rican government is pursuing this policy to lower the country's dependency of foreign oil and to reduce the amount of greenhouse gases produced. The plan also calls for an increase in ethanol producing crops and tax breaks for flex-fuel vehicles. [cite news |url= |title=Gasolineras solo venderán biocombustible desde octubre |publisher=La Nación|author=Vanessa Loaiza N. |date=2008-05-25 |accessdate=2008-06-07|language=Spanish] However, the introduction of the blend of 7% ethanol with 93% gasoline was postponed in September 2008 until the beginning of 2009. This delay was due to a request by the national association of fuel retailers to have more time available to adpat their fueling infrastructure. [cite news|url=|title=Gobierno traslada para enero mezcla de etano (Government postpones introduction of ethanol blend until January|publisher=La Nación|author=Mercedes Agüero|date=2008-09-26|accessdate=2008-10-11|language=Spanish]

El Salvador

As a result of the cooperation agreement between the United States and Brazil, El Salvador was chosen in 2007 to lead a pilot experience to introduce state-of-the-art technology for growing sugar cane for production of ethanol fuel in Central America, as this technical bilateral cooperation is looking for helping Central American countries to reduce their dependence on foreign oil. [cite web |url=|title=Centroamérica busca cooperación de Brasil para biocombustibles y comercio |publisher=La Nación |author=Oscar Batres |date=2008-05-29 |accessdate=2008-06-07|language=Spanish ]

Comparison between Brazil and the U.S.

Brazil's sugar cane-based industry is far more efficient than the U.S. corn-based industry. Brazilian distillers are able to produce ethanol for 22 cents per liter, compared with the 30 cents per liter for corn-based ethanol. ["The Economist", March 3-9th, 2007 "Fuel for Friendship" p. 44] Sugarcane cultivation requires a tropical or subtropical climate, with a minimum of 600 mm (24 in) of annual rainfall. Sugarcane is one of the most efficient photosynthesizers in the plant kingdom, able to convert up to 2% of incident solar energy into biomass. Ethanol is produced by yeast fermentation of the sugar extracted from sugar cane.

Sugarcane production in the United States occurs in Florida, Louisiana, Hawaii, and Texas. In prime growing regions, such as Hawaii, sugarcane can produce 20 kg for each square meter exposed to the sun. The first three plants to produce sugar cane-based ethanol are expected to go online in Louisiana by mid 2009. Sugar mill plants in Lacassine, St. James and Bunkie were converted to sugar cane-based ethanol production using Colombian technology in order to make possible a profitable ethanol production. These three plants will produce 100 million gallons of ethanol within five years. [cite web|url=|publisher=Miami Herald|author=Gerardo Reyes|title=Colombians in U.S. sugar mills to produce ethanol|date=2008-06-08|accessdate=2008-06-11|language=]

U.S. corn-derived ethanol costs 30% more because the corn starch must first be converted to sugar before being distilled into alcohol. Despite this cost differential in production, in contrast to Japan and Sweden, the U.S. does not import much of Brazilian ethanol because of U.S. trade barriers corresponding to a tariff of 54-cent per gallon – a levy designed to offset the 51-cent per gallon blender's federal tax credit that is applied to ethanol no matter its country of origin. [ [ U.S. Congress Stands Behind Domestic Ethanol, Extends Tariff ] ] One advantage U.S. corn-derived ethanol offers is the ability to return 1/3 of the feedstock back into the market as a replacement for the corn used in the form of Distillers Dried Grain.

Reduced petroleum imports and costs

One rationale given for extensive ethanol production in the U.S. is its benefit to energy security, by shifting the need for some foreign-produced oil to domestically-produced energy sources. [ [ Energy Security] ] Citation | last = Turon, Martin | title = [ Ethanol as Fuel: An Evironmental and Economic Analysis] | date = 1998-11-25| publisher = U.C. Berkeley, Chemical Engineering ] Production of ethanol requires significant energy, but current U.S. production derives most of that energy from coal, natural gas and other sources, rather than oil. [ [ Ethanol Can Contribute to Energy and Environmental Goals] ] Because 66% of oil consumed in the U.S. is imported, compared to a net surplus of coal and just 16% of natural gas (2006 figures), [ [ Energy INFOcard] ] the displacement of oil-based fuels to ethanol produces a net shift from foreign to domestic U.S. energy sources.

According to a 2008 analysis by Iowa State University, the growth in US ethanol production has caused retail gasoline prices to be US $0.29 to US $0.40 per gallon lower than would otherwise have been the case. [ [ Ethanol Lowers Gas Prices 29-40 Cents Per Gallon] ]

Recent patents

In 2006-2-23, Veridium Corporation announced the technology to convert exhaust carbon dioxide from the fermentation stage of ethanol production facilities back into new ethanol and biodiesel. The bioreactor process is based on a new strain of iron-loving blue-green algae discovered thriving in a hot stream at Yellowstone National Park. [ [ Veridium Patents Yellowstone Algae-Fed Bioreactor to Capture Ethanol Plant CO2 Emissions] ]

In 2006-11-14, US Patent Office approved Patent 7135308, a process for the production of ethanol by harvesting starch-accumulating filament-forming or colony-forming algae to form a biomass, initiating cellular decay of the biomass in a dark and anaerobic environment, fermenting the biomass in the presence of a yeast, and the isolating the ethanol produced. [ [ US patent 7135308] ]

Criticism and controversy

According to an April 2008 World Bank report, biofuels have caused world food prices to increase by 75-percent. [cite web |url=;_ylt=At_X.9OZ0U8sMmq0i5jdpI2GOrgF |title=Biofuels behind food price hikes: leaked World Bank report] In 2007, biofuels consumed one third of America's corn (maize) harvest. Filling up one large vehicle fuel tank one time with 100% ethanol uses enough corn to feed one person for a year. Thirty million tons of U.S. corn going to ethanol in 2007 greatly reduces the world's overall supply of grain. [cite web |url= | title= The Economist – The End Of Cheap Food] However, 31% of the corn put into the process comes out as distiller's grain, or DDGS, which is very high in protein, and is used to feed livestock. [cite web |url= | title= Amber Waves - Ethanol Reshapes the Corn Market]

Jean Ziegler, the United Nations Special Rapporteur on the Right to Food, called for a five-year moratorium on biofuel production to halt the increasing catastrophe for the poor. He proclaimed that the rising practice of converting food crops into biofuel is "A Crime Against Humanity," saying it is creating food shortages and price jumps that cause millions of poor people to go hungry. [cite web
title= Crime Against Humanity

The European Organisation for Economic Co-operation and Development warns that “the current push to expand the use of biofuels is creating unsustainable tensions that will disrupt markets without generating significant environmental benefits.” [cite web
title= Financial Times: OECD Warns Against Biofuels Subsidies

When all 200 American ethanol subsidies are considered, they cost about $7 billion USD per year (equal to roughly $1.90 USD total for each a gallon of ethanol).cite web
title= The Economist - Food Prices: Cheap No More
] When the price of one agricultural commodity increases, farmers are motivated to quickly shift finite land and water resources to it, away from traditional food crops.

The 2007-12-19 U.S. Energy Independence and Security Act of 2007 requires American “fuel producers to use at least 36 billion gallons of biofuel in 2022. This is nearly a fivefold increase over current levels.” [cite web
title= Bush Signs Energy Independence and Security Act of 2007

When cellulosic ethanol is produced from feedstock like switchgrass and sawgrass, the nutrients required to grow the cellulose are removed and cannot decay and replenish the soil. The soil is of poorer quality, and unsustainable soil erosion occurs.

Ethanol production from corn consumes large quantities of unsustainable petroleum and natural gas. Even with the most-optimistic energy return on investment claims, in order to use 100% solar energy to grow corn and produce ethanol (fueling farm-and-transportation machinery with ethanol, distilling with heat from burning crop residues, using no fossil fuels), the consumption of ethanol to replace current U.S. petroleum use alone would require about 75% of all cultivated land on the face of the Earth, with no ethanol for other countries, or sufficient food for humans and animals. [cite web
title= Global Science Forum Conference on Scientific Challenges for Energy Research: Energy At The Crossroads

Fuel system problems

Several of the outstanding ethanol fuel issues are linked specifically to fuel systems. Fuels with more than 10% ethanol are not compatible with non E85-ready fuel system components and may cause corrosion of ferrous components." [ Capability of vehicles to satisfactorily operate on Ethanol Blend petrol] " 8 August 2006. Federal Chamber of Automotive Industries. Retrieved on 2007-04-09.] Orbital Fuel Company. " [ Market Barriers to the Uptake of Biofuels Study] " May 2003. Environment Australia. Retrieved on 2007-04-29] Ethanol fuel can negatively affect electric fuel pumps by increasing internal wear, cause undesirable spark generation, [cite web
title= Ethanol Production Plant, Fuel Stock e85, Cellulosic Corn Ethanol, Prices
author= |last= |first= |authorlink= |coauthors=
date= |year= |month= |format= |work= |publisher=
pages= |language= |doi= |archiveurl= |archivedate= |quote=
accessdate= 2008-01-14
] and is not compatible with capacitance fuel level gauging indicators and may cause erroneous fuel quantity indications in vehicles that employ that system. [ " [ Ethanol Motor Fuel Storage Overview] " September 2005. Wisconsin Department of Commerce. Retrieved on 2007-04-29] It is also not always compatible with marine craft, especially those that use fiberglass fuel tanks. [cite web
title= "Ethanol fuel gunking up Island boats"
author= Dan Nakaso |date= 2007-04-11 |publisher= "Honolulu Advertiser"
accessdate= 2008-01-14
] [cite web
title= New Fuels: Gasoline and Diesel
author= Philip Gaudreau
date= |year= |month= |format= PDF |work= |publisher=
accessdate= 2008-01-14
] Ethanol is also not used in aircraft for these same reasons.

Using 100% ethanol fuel decreases fuel-economy by 15-30% over using 100% gasoline; this can be avoided using certain modifications that would, however, render the engine inoperable on regular petrol without the addition of an adjustable ECU. [cite web
title= Ethanol Facts: Engine Performance
author= |last= |first= |authorlink= |coauthors=
date= |year= |month= |format= |work= |publisher=
accessdate= 2008-01-14
] Tough materials are needed to accommodate a higher compression ratio to make an ethanol engine as efficient as it would be on petrol; these would be similar to those used in diesel engines which typically run at a CR of 20:1,cite web
title= Performance Tuning for Diesel Cars & Vans
author= |last= |first= |authorlink= |coauthors=
date= |year= 2008 |month= |format= |work= |publisher= Denbury Diesels
pages= |language= |doi= |archiveurl= |archivedate= |quote=
accessdate= 2008-01-14
] versus about 8-12:1 for petrol engines. [ cite web
title= The Science And Costs of Diesel Cars
author= Marc West |date= 2007-03-01 |work= |publisher=
accessdate= 2008-01-14

In April 2008 the German environmental minister cancelled a proposed 10% ethanol fuel scheme citing technical problems: too many older cars in Germany are unequipped to handle this fuel. Ethanol levels in fuel will remain at 5%. [ [Gabriel stoppt die Biosprit-Verordnung] Die Welt 4 April 2008]


* Citation
last = Goettemoeller, Jeffrey; Adrian Goettemoeller
title = Sustainable Ethanol: Biofuels, Biorefineries, Cellulosic Biomass, Flex-Fuel Vehicles, and Sustainable Farming for Energy Independence
year = 2007
publisher = Praire Oak Publishing, Maryville, Missouri
id = ISBN 978-0-9786293-0-4 . "Brief and comprehensive account of the history, evolution and future of ethanol."

* Citation
last = The Worldwatch Institute
title = Biofuels for Transport: Global Potential and Implications for Energy and Agriculture
year = 2007
publisher = Earthscan Publications Ltd., London, U.K.
id = ISBN 978-1-84407-422-8 . "Global view, includes country study cases of Brazil, China, India and Tanzania".


ee also

External links

* [ Ethanol blended petrol usage in Brazil]
* [,,contentMDK:21501336~pagePK:64167689~piPK:64167673~theSitePK:2795143,00.html World Bank, Biofuels: The Promise and the Risks. World Development Report 2008: Agriculture for Development]
* [$file/Bioethanol_Technolgoy_GEA_Wiegand_en.pdf Bio Ethanol Brochure]

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