Ethanol fuel

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Template:Cleanup-date Template:Not verified Template:Globalize Image:EthanolPetrol.jpg Ethanol fuel for internal combustion engines, either alone or in combination with other fuels as an oxygenate, is a valuable sustainable energy resource. This chemical derived from crops offers potential environmental and long-term economical advantages over fossil fuel.

Both ethanol and methanol are candidate fuels. While each can be obtained from petroleum or natural gas, ethanol may be the most viable because it is a renewable resource, readily obtained from sugar or starch in crops such as maize and sugarcane. Since ethanol occurs in nature whenever yeast combines with a sugar solution such as overripe fruit, most organisms have evolved some tolerance to ethanol, whereas methanol is toxic. When 10% alcohol fuel is mixed into gasoline (or petrol), the result is known as gasohol or E10. A mixture of 85% ethanol and 15% gasoline is known as E85. Other formulations involve butanol, which can also be produced by fermentation of certain plants such as rice. Sometimes ethanol is called "bioethanol".

Ethanol is also increasingly used as an oxygenate for gasoline, as a replacement for MTBE, the latter chemical being responsible for considerable groundwater and soil contamination.

Contents

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Ethanol fuels

Proposals to use alcohol as a fuel are generally directed to its use in transportation, chiefly as a total or partial replacement for gasoline in cars and other road vehicles. However, other less conventional approaches have been advanced, such as the use of alcohol in fuel cells, either directly or as a feedstock for hydrogen production. If Net Energy Analysis is accepted, then ethanol must be shown to result in positive net energy. In other words, the ethanol that is put in a car must have more energy than was used to make the ethanol. Electricity production results in a net loss of energy, showing that net energy is not the only factor - cleanliness and convenience are considered more important than the loss of energy. It remains to be seen whether factors such as cleanliness or appeals to energy independence will outweigh the loss of energy in ethanol production.

Three countries have developed significant bio-ethanol programs: Brazil and Colombia (from sugarcane), and the United States (from maize). Ethanol for industrial use is often made synthetically from petroleum feedstock, typically by the catalytic hydration of ethylene with sulfuric acid as the catalyst. This process is cheaper than production by fermentation. It can also be obtained via ethene or acetylene, from calcium carbide, coal, oil gas, and other sources.

Ethanol can be produced from a variety of crops, such as sugarcane, sugar beet, maize (corn), switchgrass, barley, hemp, kenaf, potatoes, cassava and sunflower. Agricultural alcohol for fuel requires substantial amounts of cultivable land with fertile soils and water. It is less attractive for densely occupied and industrialized regions like Western Europe. If all of Germany were to be entirely cultivated for ethanol, it would get only half of its present energy needs (including fuel and electricity). Fuel alcohol can be made from the stalks, wastes, clippings, straw, corn cobs, and other waste, meaning no additional land is needed. Using these sources for this purpose would require additional replacement animal feedstock, fertilizers and electric power plant fuels.

Directive 2003/30/EC of the European Parliament promotes the replacement of fossil fuels by biofuels: amongst them bio-ethanol to be blended into petrol. The United Kingdom has adopted a national policy of encouraging the use of biofuels including ethanol[1].

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Production and distribution

Image:Saccharum-officinarum-harvest.JPG Image:Cornfield in South Africa2.jpg Ethanol can be derived from corn, wheat, potato wastes, cheese whey, rice straw, sawdust, urban wastes, paper mill wastes, yard clippings, molasses, sugar cane, seaweed, surplus food crops, and other cellulose waste. Petroleum is also used to make industrial ethanol.

Ethanol may be produced via biochemical conversion technologies or distillation. While the latter is state of the art the first is still under development [2].

Ethanol, which is the same chemical as the alcohol in alcoholic beverages, can reach 96% purity by volume by distillation, and is as clear as water. This is enough for straight-ethanol combustion. Ethanol in water is an azeotropic mixture which cannot be purified beyond 96% by distillation. For blending with gasoline, purities of 99.5 to 99.9% are required, depending on temperature, to avoid separation. This is done using additional industrial processes. Today, the most widely used purification method is a physical adsorption process using molecular sieves. Ethanol is flammable and pure ethanol burns more cleanly than many other fuels. If derived from biomass, the combustion of ethanol produces no net carbon dioxide. When fully burned, its combustion only products are carbon dioxide and water, which are also the by-products of cellulose waste decomposition. For this reason, it is favoured for environmentally conscious transport schemes and has been used to fuel public buses. However, pure ethanol reacts with or dissolves certain rubber and plastic materials and cannot be used in unmodified engines. Additionally, pure ethanol has a much higher octane rating (113) than ordinary gasoline, requiring changes to the compression ratio or spark timing to obtain maximum benefit.[3] To change a gasoline-fueled car into a pure-ethanol-fueled car, larger carburetor jets (about 30-40% larger by area) are needed. (Methanol requires an even larger increase in area, to roughly 50% larger.) A cold starting system is also needed to ensure sufficient vaporization for temperatures below 15 °C (59 °F) to maximize combustion and minimize uncombusted nonvaporized ethanol. If 10 to 30% ethanol is mixed with gasoline, no engine modification is typically needed. Many modern cars can run on the mixture very reliably.

A mixture containing gasoline with approximately 10% ethanol is known as gasohol. It was introduced nationwide in Denmark, and in 1989, Brazil produced 12 billion litres of fuel ethanol from sugar cane, which was used to power 9.2 million cars. It is also commonly available in the Midwestern United States and is the only type of gasoline allowed to be sold in the state of Minnesota. The most common gasohol variant is "E10", containing 10% ethanol and 90% gasoline. Other blends include E5 and E7. These concentrations are generally safe for recent, unmodified automobile engines, and some regions and municipalities mandate that the locally-sold fuels contain limited amounts of ethanol. One way to measure alternative fuels in the US is the "gasoline-equivalent gallons" (GEG). In 2002, the U.S. used as fuel an amount of ethanol equal to 137 petajoules (PJ), the energy of 1.13 billion US gallons (4,280,000 m³) of gasoline. This was less than 1% of the total fuel used that year.[4]

Image:E85bus.jpg The term "E85" is used for a mixture of 15% (by volume) gasoline and 85% ethanol. This mixture has an octane rating of about 105. This is down significantly from pure ethanol but still much higher than normal gasoline. The addition of a small amount of gasoline helps the engine under cold start conditions. E85 does not always contain exactly 85% ethanol. In winter, especially in colder climates, additional gasoline is added (to facilitate cold start). E85 has traditionally been similar in cost to gasoline, but with the large oil price rises of 2005 it has become common to see E85 sold for as much as $0.70 less per gallon than gasoline, making it highly attractive to the small but growing number of motorists with cars capable of burning it. With no real hope of large long-term reductions in oil prices, the long term cost-competitiveness (even without tax subsidies) of E85 seems assured.

Beginning with the model year 1999, an increasing number of vehicles in the world are manufactured with engines which can run on any gasoline from 0% ethanol up to 85% ethanol without modification. Many light trucks (a class containing minivans, SUVs and pickup trucks) are designed to be dual fuel or flexible fuel vehicles, since they can automatically detect the type of fuel and change the engine's behavior, principally air-to-fuel ratio and ignition timing to compensate for the different octane levels of the fuel in the engine cylinders.

In the past, when farmers distilled their own ethanol, they sometimes used radiators as part of the still. The radiators often contained lead, which would get into the ethanol. Lead entered the air during the burning of contaminated fuel, possibly leading to neural damage. However this was a relatively minor source of lead since at the time tetraethyl lead was used as a mainstream gasoline additive. Today, ethanol for fuel use is produced almost exclusively from purpose built plants eliminating any use of lead.

In Brazil and the United States, the use of ethanol from sugar cane and grain as car fuel has been promoted by government programs. Some individual U.S. states in the corn belt began subsidizing ethanol from corn (maize) after the Arab oil embargo of 1973. The Energy Tax Act of 1978 authorized an excise tax exemption for biofuels, chiefly gasohol. The excise tax exemption alone has been estimated as worth US$1.4 billion per year. Another U.S. federal program guaranteed loans for the construction of ethanol plants, and in 1986 the U.S. even gave ethanol producers free corn.

In August 2005, President Bush signed a comprehensive energy bill which included a requirement to increase the production of ethanol and biodiesel from 4 to 7.5 billion US gallons (15,000,000 to 28,000,000 m³) within the next ten years. It is expected that in the short term the majority of this increase will come from ethanol produced from corn.

Today the US Gas usage is approximately 360,000,000 U.S. gallons per day. 28.8% of the US surface area (~ 685,000,000 acres) would be required to grow the biomass required to produce enough ethanol to cover current domestic US gas demand. The US currently has 455,000,000 acres of arable land. There are currently about 80 million acres of corn planted in the US (~40% of the world's supply).

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Other alcohols

See also Methanol fuel

Although not as common as ethanol, other fuel alcohols have been considered, notably methanol, butanol, and propanol. These alcohols are toxic, although the latter two are considerably less toxic than methanol, and considerably less volatile. In particular, butanol has a high flashpoint of 35 °C, which is a benefit for fire safety, but a difficulty for starting engines, particularly in cold weather. (In comparison, ethanol has a flashpoint of 13 °C; methanol has a flashpoint of 11 °C; and propanol has a flashpoint of 15 °C.)

The fermentation processes to produce butanol and propanol from cellulose are fairly tricky to execute, and the Weizmann organism (Clostridium acetobutylicum) used to perform these conversions produces an extremely unpleasant smell that must be considered when designing and locating a fermentation plant. This organism also dies when the butanol content of whatever it is fermenting hits 7%. For comparison, yeast dies when the ethanol content of its feedstock hits 14%.

One advantage shared by all four alcohols is octane rating. Butanol has the additional attraction that its energy per kilogram is closer to gasoline than the other alcohols (while still retaining over 25% higher octane rating).

As of 2005, production of all four alcohols from petroleum is cheaper than fermentation and extraction from biomass, but this is expected to change as fermentation and extraction processes become more efficient while petroleum becomes more expensive.

Methanol fuel is widely used in motorsports, especially in Drag Racing, Monster Trucks, and Mud Racing. Mark Thomas has used Ethanol on his IHRA Top Alcohol Funny Car for years. In 2007, the Indy Racing League will use ethanol exclusively in their cars.

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Ethanol and hydrogen

Hydrogen is being analyzed as an alternative fuel, creating a hydrogen economy. Because hydrogen in its gaseous state takes up a very large volume when compared to other fuels, logistics becomes a difficult problem. One possible solution is to use ethanol to transport the hydrogen, then liberate the hydrogen from its associated carbon in a hydrogen reformer and feed the hydrogen into a fuel cell. Alternatively, some fuel cells (DEFC Direct-ethanol fuel cell) can be directly fed by ethanol or methanol. As of 2005, fuel cells are able to process methanol more efficiently than ethanol.

In early 2004, researchers at the University of Minnesota announced the invention of a simple ethanol reactor that would feed ethanol through a stack of catalysts, and output hydrogen suitable for a fuel cell. The device uses a rhodium-cerium catalyst for the initial reaction, which occurs at a temperature of about 700 °C. This initial reaction mixes ethanol, water vapor, and oxygen and produces good quantities of hydrogen. Unfortunately, it also results in the formation of carbon monoxide, a substance that "chokes" most fuel cells and must be passed through another catalyst to be converted into carbon dioxide. (The odorless, colorless, and tasteless carbon monoxide is also a significant toxic hazard if it escapes through the fuel cell into the exhaust, or if the conduits between the catalytic sections leak.) The ultimate products of the simple device are roughly 50% hydrogen gas and 30% nitrogen, with the remaining 20% mostly composed of carbon dioxide. Both the nitrogen and carbon dioxide are fairly inert when the mixture is pumped into an appropriate fuel cell. The carbon dioxide is released back into the atmosphere, where it can be reabsorbed by plant life. No net carbon dioxide is released, though it could be argued that while it is in the atmosphere, it does act as a greenhouse gas.

EEI has developed a new method for producing butanol from biomass. This process involves the use of two separate micro-organisms in sequence to minimize production of acetone and ethanol byproducts. Interestingly, this process produces significant amounts of hydrogen as well as butanol. [5][6]

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Alternate sources to corn

Sugar cane grows in the extreme southern United States, but not in the cooler climates where corn is dominant. However, many regions that currently grow corn are also appropriate areas for growing other crops that can be used for energy production. These crops include corn stover, sugar beets, wheat straw, hybrid poplars, and dedicated herbaceous biomass feedstocks such as switchgrass or bermudagrass. Some studies indicate that using these sugar beets would be a much more efficient method for making ethanol in the U.S. than using corn. United States Department of Energy reports have shown that at a minimum farmgate price, hybrid poplars and switchgrass would be economically advantageous over conventional crops in certain regions of the U.S.

In the 1980s, Brazil seriously considered producing ethanol from cassava, a major food crop with massive starchy roots. However yields were lower than sugarcane, and the processing of cassava was considerably more complex, as it would require cooking the root to turn the starch into fermentable sugar. The babaçu plant was also investigated as a possible source of alcohol.

Brazil now makes ethanol out of sugar cane. Ethanol made out of sugar cane is almost eight times as efficient as ethanol made out of corn. [7]

There is also growing interest in the use of waste biomass as a source of fuel alcohol. New technologies such as cellulose to ethanol production could provide much higher positive energy ratios of 2 to 3 times more energy in ethanol produced than input. Cellulose to ethanol production could also run on any cellulose and hemicellulose source from farm waste, hay/grass, basically any plant matter including wood, cardboard and paper. Theoretically farms could produce fuel without sacrificing food production, because all that is needed is the left over plant matter after harvesting. Cellulose to ethanol production is still in development and has seen limited use in industrial ethanol production. However, a bioenergy corporation in Canada is producing 1 million gallons/year of cellulosic ethanol from their Ottawa facility. Using current technologies, 1 ton of biomass (such as switchgrass) would be able to produce 80 gallons of ethanol using a conventional enzymatic fermentation process. The biggest challenges in using cellulose as a feedstock is the treatment and disposal of process waste and the conversion of C5 sugars (hemicellulose). Lignin, a part of the cell wall that provides plant structure, does not readily break down to simple sugars but has an energy equivalent of soft coal. Lignin would be incinerated to produce energy for the ethanol plant and surrounding areas or gasified to produce a syngas (hydrogen and carbon dioxide). Unlike grain based processes which produce a by-product known as distillers grain with minimal waste treatment needs, cellulosic processes are typically effluent and waste treatment intensive. Cellulose to ethanol production is a focus of President Bush's administration. Increased ethanol production from cellulosic sources was one method that President George W. Bush mentioned in his 2006 State of the Union Address to decrease America's "addiction to foreign oil." [8]

Distiller grain is a protein enriched animal feed with much higher nutritional value than natural grain and is typically priced at less than half that of natural grain. It therefore tends to be a desirable product for animal feeders. Approximately one-third of grain usage in the production of ethanol in modern plants is recovered as distillers grain.[9] [10] [11]

At this time, most of the different processes for converting biomass into ethanol and other fuels are very complicated and not particularly efficient. A few processes have seen increasing buzz, including thermal depolymerization (though that process produces what is described as light crude oil).

It is possible to decompose cellulose into sugar in strong or weak solutions of sulphuric acid, but this process also decomposes and wastes perhaps half the potential sugar content and creates large amounts of acidic waste, so scientists are searching for more efficient and less polluting enzymatic and microbial processes for breaking down cellulose into sugar.

Another approach under development is to gasify biomass by heating it in an oxygen-poor environment. This yields hydrogen, methane and carbon monoxide as well as noncombustible carbon dioxide and nitrogen compounds. Bacterial cultures have been isolated that can convert the reactive gasses into ethanol, which is then distilled out of the liquid medium.

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Net fuel energy balance

For ethanol to contribute significantly to transportation fuel needs, it would need to have a positive net energy balance. To evaluate the net energy of ethanol four variables must be considered: the amount of energy contained in the final ethanol product, the amount of energy directly consumed to make the ethanol (such as the diesel used in tractors), the quality of the resulting ethanol compared to the quality of refined gasoline and the energy indirectly consumed (in order to make the ethanol processing plant, etc). Although a topic of debate, some research that ignores energy quality suggests it takes as much or more fossil fuel energy (in the forms of diesel, natural gas and coal) to create an equivalent amount of energy in the form of ethanol. In other words, the energy needed to run the tractors, produce the fertilizer, process the ethanol, and the energy associated with the wear and tear on all of the equipment used in the process (known as fixed asset depreciation to economists) may be more than the energy derived from burning ethanol. Two important flaws are cited in response to that argument: (1) the energy quality is ignored, which economic effects are large. Principal economic effects of energy quality comparison are the cleanup costs of soil contamination stemming from gasoline releases to the environment and medical costs from air pollution resulting from refining and burning gasoline. and (2) the inclusion of development of ethanol plants instills a bias against that product based strictly upon the pre-existence of gasoline refining capacity. The real decision should be based upon the long term economic and social returns. The first counter-argument, however, is specious, in that burning a gallon of cleaner ethanol is still pointless if it implicitly requires burning 2 gallons of dirty gasoline to create that ethanol in the first place.

Much of the current academic discussion regarding ethanol currently revolves around issues of system borders. This refers to how complete of a picture is drawn for energy inputs. There is debate on whether to include items like the energy required to feed the people tending and processing the corn, to erect and repair farm fences, even the amount of energy a tractor represents. In addition, there is no consensus on what sort of value to give the rest of the corn (such as the stalk), commonly known as the 'coproduct.' Some studies leave it on the field to protect the soil from erosion and to add organic matter, while others take and burn the coproduct to power the ethanol plant, but do not address the resulting soil erosion (which would require energy in the form of fertilizer to replace). Depending on the ethanol study you read, net energy returns vary from .7-1.5 units of ethanol per unit of fossil fuel energy consumed. For comparison, that same one unit of fossil fuel invested in oil and gas extraction (in the lower 48 States) will yield 15 units of gasoline, a yield an order of magnitude better than current ethanol production technologies, ignoring the energy quality arguments above. [12].

Extraction is not the same as production. Each gallon of extracted oil is a gallon of depleted oil. To fairly compare the energy balance of gas production to ethanol production, one must also calculate the energy required to produce oil from the atmosphere and feed it back into the earth, a process that would make gasoline production fractionally efficient compared to ethanol. It is suggested that an energy balance of 200%, or two units of ethanol per unit of fossil fuel invested, is needed before ethanol mass-production will become economically feasible.

Switching to a system with negative fuel energy balance could increase the consumption of non-alcohol fuels. Such a system may only be worth considering as a way of exploiting and converting non-liquid fuels through the production of ethanol for transportation use, such as coal, natural gas, or biofuel from crop residues. (Indeed, many U.S. proposals assume the use of natural gas for distillation and fertilizer production.) However, many of the expected environmental and sustainability advantages of alcohol fuels may not be realized in a system with negative fuel balance. Before conclusions are drawn on the energy fuel balance calculations it would be necessary to factor in the annual medical costs associated with air pollution from gasoline and soil remediation costs of the gasoline alternative; combined the annual costs of these penalties to gasoline are on the order of one to ten billion dollars per annum in the U.S. and potentially treble that value worldwide.

Even a positive but small energy balance would be problematic: if the net fuel energy balance is 50%, then, in order to eliminate the use of non-alcohol fuels, it would be necessary to produce two units of alcohol for each unit of alcohol delivered to the consumer.

In this regard, geography is the decisive factor. In tropical regions with abundant water and land resources, such as Brazil, the viability of production of ethanol from sugarcane is no longer in question; in fact, the burning of sugarcane residues (bagasse) generates far more energy than needed to operate the ethanol plants, and many of them are now selling electric energy to the utilities. However, while there may be a positive net energy return at the moment, recent research suggests that the sugercane plantations are not sustainable in the long run, as they are depleting the soil of nutrients and carbon matter (Reijnders 2004).

The picture is different for other regions, such as most of the United States, where the climate is too cool for sugarcane. In the U.S., agricultural ethanol is generally obtained from grain, chiefly corn.

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Ethanol energy balance in the United States

Template:TotallyDisputed-section The total energy needed to produce ethanol from grain — including fermentation, fertilizing, fuel for farm tractors, harvesting and transporting the grain, building and operating an ethanol plant, and the natural gas used to distill corn sugars into alcohol — is less than the energy content of ethanol. Studies have concluded that ethanol production yields more energy than it consumes Most agree on a ratio of 1.34:1. It is also being discovered that corn ethanol yields 26% more energy than is used to make it. [13] and see below).

One study by Cornell University ecology professor David Pimentel concluded that the use of corn ethanol for fuel would have a negative net energy balance. Pimentel's study was disputed by a number of researchers, forcing him to revise his figures. Still, in August 2003 (and again in March 2005), he stated in a Cornell bulletin that production of ethanol from corn takes 29% more energy than it produces, ethanol from switch grass requires 45% more energy and ethanol from wood biomass requires 57% more energy that it produces [14].

Using old data biases the outcome in these studies. According to the USDA, farms have become more energy efficient since 1978 due in large part to replacing gasoline powered equipment with more fuel-efficient diesel engines. Total farm energy use peaked in 1978 at 2,244 trillion Btu (2.368 EJ), but by 2000 had dropped to about 1,600 trillion Btu (1.7 EJ). In the meantime, corn production rose from an average of 110 bushels per acre (6.9 Mg/ha) in 1980 to 140 bushels per acre (8.8 Mg/ha) in 2000.

Pimentel concluded that the yield was 218 US gallons per acre (204 m³/km²) of gasoline equivalent, due to the energy in ethanol being only 66% that of gasoline. Pimentel also calculated that corn (maize) production requires about 115 US gallons per acre (108 m³/km²) of gasoline equivalent. Thus, he calculated a net energy production of 103 US gallons per acre (96 m³/km²), while his studies somehow all concluded a net energy loss in producing ethanol. Critics of Pimentel's study cite questionable deductions, for example; 1,000,000 Btu per acre (260 kJ/m²) for labor, 5,656,000 Btu per acre (1474 kJ/m²) for machinery, as well as additional deductions for steel and concrete production and construction of ethanol refineries, while not saying from where these numbers were derived. (Shapouri, Hosein, James A. Duffield, Michael Wang. The Energy Balance of Corn Ethanol: An Update. USDA: Office of the Chief Economist; Office of Energy Policy and New Uses. Washington, DC. July, 2002) Although ethanol does have 66% of the energy per unit of volume of gasoline, its higher octane rating enables higher compression and therefore higher efficiency engines.

The focus of the USDA report, and others, was on ethanol and the energy balance equation, but according to a report by the Minnesota Department of Agriculture, when taking into account the energy needed to extract, transport and refine crude oil into gasoline, the final energy product of gasoline has an energy ratio of 0.805. That means ethanol production is 81% more energy efficient than gasoline, without factoring in the energy qualtity considerations. (Groschen [15])

Continual refinements to ethanol production procedures (including steady gains in agricultural productivity) advance the ethanol the benefit/cost ratio, and most studies of modern systems indicate that they now have a positive net energy balance. Also, when ethanol is mixed with water vapor and converted into hydrogen, it does not need to be as pure as when it is used in a combustion engine, making the process more efficient. (see source below)

Many other studies of corn ethanol production have been conducted, with greatly varied net energy estimates. Most indicate that production requires energy equivalent to 1/2, 2/3, or more of the fuel produced to run the process. A 2002 report by the United States Department of Agriculture concluded that corn ethanol production in the U.S. has a net energy value of 1.34, meaning 34% more energy was produced than what went in. This means that 75% (1/1.34) of each unit produced is required to replace the energy used in production. The study also concluded that the energy used to produce and convert the ethanol was from abundant domestic sources, with only 17% of the energy used coming from liquid fuels, therefore, for every 1 unit of energy from of liquid fuel used, such as gasoline or diesel fuel, there was a gain of 6.34 units of energy. MSU Ethanol Energy Balance Study: Michigan State University, May 2002. This comprehensive, independent study funded by MSU shows that corn ethanol production has a net energy value of 1.56: it produces 56% more energy per unit volume of ethanol than it consumes. Nevertheless, as noted earlier, these relatively small energy gains are problematic, for they imply that between 2.79 (assuming net energy value 1.56) and 3.94 (assuming net energy value 1.34) units of ethanol must be produced for each unit of ethanol that can be sold to consumers. Actual net energy values might be improved by measures such as burning corn stalks (which are not fermentable using current technology) to run some parts of the corn ethanol production process that currently consume petroleum, gas, or ethanol (similarly to the way bagasse is currently burned to produce energy to run the ethanol production facilities in Brazil). As of 2005, ethanol production from corn may require an increase in the cost of petroleum before becoming economically viable without government subsidies. Although for periods in the year 2005 ethanol traded for less than gasoline and diesel before any subsidy.

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Arguments and criticisms

The use of alcohol as fuel leads to several beneficial effects to the environment, greater independence from petroleum, and economic advantages. Critics dispute some of these arguments, claiming that the switch could be expensive, and object to perceived need for increased government subsidies, taxes, and regulations.

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Air pollution

There has long been widespread acknowledgement that ethanol is a cleaner-burning fuel than gasoline. Ethanol has far fewer standard regulated pollutants such as carbon monoxide and hydrocarbons, compared with plain gasoline in equivalent tests. See, for example, the air pollution and environmental studies listed at the Renewable Fuels Association website (http://www.ethanolrfa.org/pubs.shtml).

In a gasoline blend, an issue exists regarding evaporative hydrocarbon emissions. For example, the conservative group RPPI claims that "adding ethanol to gasoline will at best have no effect on air quality and could even make it worse. Studies show ethanol could even increase emissions of nitrogen oxides and volatile organic compounds, which are major ingredients of smog." [16] However analysis by the state of Pennsylvania [17] and other researchers indicate that ethanol evaporative emissions "lose one-half gram per mile per vehicle less than conventional gasoline vehicles." They insist that if a significant number of ethanol-based vehicles were on the road, air quality would greatly improve.

Ethanol in a blend with gasoline replaces tetra ethyl lead, benzene and MTBE, all of which are additives intended to raise octane levels. Ethanol, with an octane rating of 110, far surpasses regular gasoline and precludes the need for additives. However, ethanol can increase the vapor pressure of gasoline causing increased gasoline evaporative emissions.

Ethanol as a straight fuel is cleaner than gasoline in its own right, a fact recognized from the dawn of the automotive age. See, for instance, Kovarik's "Fuel of the Future" (http://www.radford.edu/~wkovarik/lead).

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Soil contamination

Both gasoline (which contains benzene) and MTBE are soil contaminants, and their continued use adds annually to the ultimate remediation costs of restoring groundwater quality and soil integrity. While ethanol itself poses lesser corresponding threats to aquifer purity, soil integrity or ecosystems, corn production can lead to environmental impacts, including contamination of groundwater and surface waters with fertilizer and pesticide products, and loss of soil to wind and water erosion. The monetary costs of petroleum fuel soil contamination are quite large, since identified sites' cleanup costs in the U.S. alone exceed $10,000,000,000[18][19]. In 2004 the [EPA] stated that 132,000 sites required cleanup. A number of sources have established the typical cost of remediating a petroleum release cleanup at $50,000 to $500,000. The fertilizer and pesticide costs of soil cleanup are more difficult to quantify, since fertilizer runoff costs primarily manifest as surface water eutrophication, and are not always mandated for cleanup. Pesticide cleanups are much less frequent than petroleum, but have hidden, difficult to quantify costs of ecosystem damage.

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Fire safety

Ethanol appears to be less of a fire hazard than gasoline; while methanol, being more volatile, is somewhat more prone to fire and explosions, since ethanol and methanol dissolve in water (rather than floating on it like gasoline), their fires can be extinguished with ordinary water hoses.

One of the problems with accidental combustion of pure ethanol is that it burns with a dim, blue flame, with invisible smoke. Methanol flames are dim enough to be considered invisible in daylight. Blending significant amounts of gasoline produces a highly visible flame; small quantities of dye can also produce this effect.

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Greenhouse gases

A separate (and perhaps more important) benefit of switching to an ethanol fuel economy would be the decreased net output of the greenhouse gas carbon dioxide (CO2), since the amount of CO2 that would be liberated in the manufacture and consumption of ethanol would be absorbed cyclically in production of new fuel crops. In contrast, the burning of fossil fuels injects massive amounts of "new" CO2 into the atmosphere, without creating a corresponding sink.

This advantage will be accrued only with agricultural ethanol, not with ethanol derived from petroleum — which, due to its much smaller cost, presently accounts for most of the alcohol produced for industrial consumption. This point must be taken into account when estimating the cost of the switch.

However, this assumes that production processes such as distillation and fertilizer production, which require large amounts of energy, would be done without using fossil fuels.

As all fossil fuels are derived from prehistoric internment of carbon dioxide this could potentially contribute to restoring the Earth's atmosphere to that of the Holocene Climatic Optimum.

It is not at all clear whether the corn-based ethanol cycle releases less carbon dioxide per unit of useable energy than burning fossil fuels directly. Factors in the carbon dioxide balance include the following:

  • Carbon dioxide released from burning fossil fuels in the production of ethanol.
  • Carbon dioxide uptake by the growing plants.
  • Carbon dioxide released from the stalks, roots, etc., as they decay or are used.
  • Carbon dioxide released from the corn as it ferments, which may be used prior to release.
  • Carbon dioxide released by burning the ethanol for fuel, which is lower per unit of useable energy than fossil fuels.
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Renewable resource

According to its proponents, another advantage of (agricultural) alcohol as a fuel is that it is a renewable energy source that will never be exhausted; whereas an economy based on fossil fuels will sooner or later collapse when the world runs out of oil.

David Pimentel disputes that "ethanol production from corn" is a renewable energy source. However, Pimentel's studies have been widely discredited, and also fails to compare other viable sources of ethanol such as Sugar beets, Sugarcane, and Sweet Potatoes.

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Dependency on foreign oil

A somewhat related argument is that developed regions like the United States and Europe consume much more fossil fuels than they can extract from their territory, therefore becoming dependent upon foreign suppliers as a result. Even if the energy balance is negative, US production involves mostly domestic fuels such as natural gas and coal, so the impact on oil importation is still positive.

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Statism

Some critics, mainly on ideological grounds, dislike the idea of an ethanol economy because they see it as leading to increased government subsidy for corn-growing agribusiness, and statism. The Archer Daniels Midland Corporation of Decatur, Illinois, better known as ADM, the world's largest grain processor, produces 40% of the ethanol used to make gasohol in the U.S. The company and its officers have been eloquent in their defense of ethanol and contributors to both political parties; petroleum companies have been consistent donors to both political parties as well.

One U.S. government study, Tax Incentives for ethanol and petroleum, examined subsidies historically given to the oil industry and to the ethanol industry and found that the amounts of those to the oil industry are far higher. However, this study applies only to historical subsidies and doesn't investigate the question of what the case would be if petroleum fuels were substantially replaced by ethanol.

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Cost

Some economists have argued that using bioalcohol as a petroleum substitute is economically infeasible because the energy required to grow the corn and other crops used as fuel is greater than the amount ultimately produced. They argue that government programs that mandate the use of bioalcohol are simply agricultural subsidies enacted to gain votes from heavily agricultural states, especially Iowa.

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Ethanol fuel in Colombia

Colombia’s fuel ethanol program got a start in 2002 when the government passed a law which mandates oxygen enrichment of the gasoline. This was initially done to reduce carbon monoxide and unburned hydrocarbon emissions from cars. Later regulations exempted biomass derived ethanol from some taxes than gasoline does have, thus making ethanol cheaper than gasoline. This trend was reinforced when petroleum prices went up starting in 2004 and with it the interest in renewable fuels (at least for cars). In Colombia the price of both gasoline and ethanol are controlled by the government. Complementing this ethanol program, is a biodiesel program to oxygenate diesel fuel and produce a renewable fuel from vegetable oil.

Initially all the interest in ethanol production has come from the existing sugar industry, as it is relatively easy to add an ethanol back end to a sugar mill and the energy usage is similar to than needed to produce sugar. The government aims to gradually convert the nation’s auto fuel supplies to a mixture of 10 percent ethanol and 90 percent gasoline. Ethanol plants are being encouraged by tax breaks. There has been interest in ethanol plants from yuca (cassava) and from new sugar cane plantations, but producing inexpensive carbohydrates has not been achieved.

The first fuel ethanol plant in Colombia began production in October 2005, with output of 300,000 liters a day in the Cauca deparment. By March 2006 five plants, all in the Cauca Valley are operational with a combined capacity of 1,050,000 liters per day or 357 million liters per year. In the Cauca Valley of Colombia sugar is harvested year round and the new destilleries have very high availability. The total investment in these plants is $100 million. By 2007, Colombia hopes to have a capacity of 2,500,000 liters per day, which is the requirement for adding 10% ethanol to the gasoline. The ethanol fuel produced is currently used in the main cities close to the Cauca Valley, such as Bogota, Cali, and Pereira. There is not enough production for the rest of the country.

Ethanol production should help to decrease Colombia’s dependency on gasoline at a time when its oil production is decreasing as well as reduce emissions of greenhouse gases. However, in the past year, many small amounts of petroleum deposits have been discovered throughout Colombia. It is estimated that Colombia is sitting on 5 billion barrels of petroleum.

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Ethanol fuel in Brazil

Main article: Ethanol fuel in Brazil

Today, Brazil is the largest producer and consumer of ethanol fuel in the world. Since the 1980s, Brazil has developed an extensive domestic ethanol fuel industry upon sugarcane production and refining. In 2006, Brazil became energy self-sufficient thanks to its ethanol program and the recent discovery of new deep-water oil fields. Ethanol plants in Brazil maintain a positive (+34%) energy balance by burning the non-sugar waste from sugarcane.

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Ethanol fuel in the United States

One criticism of ethanol usage in the United States is its availability. Roughly 600 gas stations, out of a total of 200,000 carry E85 pumps. If a wide adoption strategy were to be implemented, far greater availability would have to come to fruition. Another aspect of its availability is that it is currently only available in the relatively sparsely populated midwest, where the ethanol is refined (see below). As of April 12, 2006 in the US, there are 4485.9 million gallons per year capacity for ethanol production with capacity of 2169.5 million gallons per year under construction. [20]

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Ethanol fuel in the Midwest

The so-called corn belt in the Midwestern United States produces large amounts of corn. Sugars from this corn are used to make ethanol. Minnesota has pioneered the use of ethanol fuel mixes in the United States, and currently it is the only state in the U.S. in which all gasoline mixes must have at least 10% ethanol (90% gasoline) by volume. Laws have been passed which mandate a 20% mix in all gasoline in the state by 2013.[21] There are almost 600 gas stations in the United States that serve E85[22] (almost 200 in Minnesota alone), which is a fuel mix of 85% ethanol and 15% gasoline.[23]

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U.S. National security

It is believed by some (including former CIA director James Woolsey and Frank Gaffney, President Reagan's undersecretary of defense [24]) that oil consumption in the U.S. contributes in a large way to the funding of terrorism. Oil is the primary source of revenue for many Mid-East countries. Many of these countries are thought to harbor and/or fund terrorist organizations. The use of alternative fuels would divert money away from these nations. Ideally, instead of funding terrorism, this money would then be used to fuel the U.S. economy. In any case, the U.S. would have considerable national security resources freed, if it did not have the need to protect supplies of Mid-East oil.

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See also

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External links

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