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Biofuel

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For articles on specific fuels used in vehicles, see Biogas, Bioethanol, Biobutanol, Biodiesel, and Straight vegetable oil

Biofuel is derived from biomass — recently living organisms or their metabolic byproducts, such as manure from cows. It is a renewable energy source, unlike other natural resources such as petroleum, coal, and nuclear fuels.

One definition of biofuel is "any fuel with an 80% minimum content by volume of materials derived from living organisms harvested within the ten years preceding its manufacture".[citation needed]||}}

Like coal and petroleum, biomass is a form of stored solar energy. The energy of the sun is "captured" through the process of photosynthesis in growing plants. (See also: Systems ecology) One advantage of biofuel over most other fuel types is that it is biodegradable, and so relatively harmless to the environment if spilled.

Agricultural products specifically grown for use as biofuels include corn and soybeans, primarily in the United States; flaxseed and rapeseed, primarily in Europe; sugar cane in Brazil; and palm oil in South-East Asia. Biodegradable outputs from industry, agriculture, forestry and households can be used; examples include straw, timber, manure, rice husks, sewage, biodegradable waste, and food leftovers. They are converted to biogas through anaerobic digestion. Biomass used as fuel often consists of underutilized types, like chaff and animal waste. The quality of timber or grassy biomass does not have a direct impact on its value as an energy-source.

Much research is being done about the use of microalgae as an energy source, with applications for biodiesel, ethanol, methanol, methane, and even hydrogen. Use of hemp is increasing, but politics restrains it.

In some industrialized countries like Germany, food is cheaper than fuel compared by price per joule [citation needed]||}}, mostly because fuel is taxed more than food. Central heating units supplied by food-grade wheat or maize are available.

Biofuel can be used both for central and decentralized production of electricity and heat. As of 2005, bioenergy covers approximately 15% of the world's energy consumption [citation needed]||}}. Most bioenergy is consumed in developing countries and is used for direct heating, as opposed to electricity production.

The production of biofuels to replace oil and natural gas is in active development, focusing on the use of cheap organic matter (usually cellulose, agricultural and sewage waste) in the efficient production of liquid and gas biofuels which yield high net energy gain. The carbon in biofuels was recently extracted from atmospheric carbon dioxide by growing plants, so burning it does not result in a net increase of carbon dioxide in the Earth's atmosphere. Therefore, many people believe that a way to reduce the amount of carbon dioxide released into the atmosphere is to use biofuels to replace non-renewable sources of energy.

Dried compressed peat is also sometimes considered a biofuel. However, it does not meet the criteria of being a renewable Biofuel form of energy, or of the carbon being recently absorbed from atmospheric carbon dioxide by growing plants. Though more recent than petroleum or coal, on the time scale of human industrialisation, peat is a fossil fuel and burning it does contribute to atmospheric CO2.

History

Solid biofuels such as wood or dried waste have been used since man learned to control fire.

Liquid biofuels for industrial applications was used since the early days of the car industry. Nikolaus August Otto, the German inventor of the combustion engine, conceived his invention to run on ethanol. Rudolf Diesel, the German inventor of the Diesel engine, conceived it to run on peanut oil. Henry Ford originally had designed the Ford Model T, a car produced from 1903 to 1926, to run completely on ethanol, after surreptitious efforts [citation needed]||}} were successful at thwarting Ford's desires to mass produce electric cars. However, when crude oil was cheaply extracted from deeper in the soil (thanks to oil reserves discovered in Pennsylvania and Texas), cars began using fuels from oil.

Nevertheless, before World War II, biofuels were seen as providing an alternative to imported oil in countries such as Germany, which sold a blend of gasoline with alcohol fermented from potatoes, called Reichskraftsprit. In Britain, grain alcohol was blended with petrol by the Distillers Company Limited under the name Discol and marketed through Esso's affiliate Cleveland.

After the war, cheap Middle Eastern oil lessened interest in biofuels. But the oil shocks of 1973 and 1979 increased interest from governments and academics. The counter-shock of 1986 again reduced oil prices and interest. But since about 2000, rising oil prices, concerns over the potential oil peak, greenhouse gas emissions (global warming), and instability in the Middle East are pushing renewed interest in biofuels. Government officials have made statements and given aid in favour of biofuels. For example, US president George W. Bush said in his 2006 State of the Union speech that he wants the US to replace 75% of the oil it imports from the Middle East by biofuels by 2025.

Examples

Alcohols

Biologically produced alcohols, most commonly ethanol and methanol, and less commonly propanol and butanol, are produced by the action of microorganisms and enzymes through fermentation — see alcohol fuel.

  • Methanol, which is now produced from natural gas, can also be produced from biomass — although this is not economically viable at present. The methanol economy is an interesting alternative to the hydrogen economy.
  • Biomass-to-liquid are fuels produced by catalysis from syngas, which is produced from biomass by gasification. [1]
  • Ethanol fuel produced from sugar cane is used as automotive fuel in Brazil. Ethanol produced from corn is used mostly as a gasoline additive (oxygenator) in the US, but direct use as fuel is growing rapidly. However, corn-based ethanol is very energy inefficent - around 3/4ths of a gallon of fuel is required to produce one gallon of ethanol (as a comparison, about 1/20th of a gallon of fuel (6%) is required to produce one gallon of gasoline). In addition, corn prices are rising as corn-based ethanol production grows. Cellulosic ethanol is manufactured from the cellulose of a wide variety of plants, including cornstalks, poplar trees, and switchgrass. It can also be manufactured from waste left over from the forest products industry. Iogen Corporation of Ontario, Canada is manufacturing it from wheat, oat and barley straw (an agricultural waste product) and other companies are attempting to do the same [2]. ETBE containing 47% ethanol is the biggest biofuel contributor in Europe.
  • Butanol is formed by ABE fermentation (acetone, butanol, ethanol) and experimental modifications of the process show potentially high net energy gains with butanol as the only liquid product. Allegedly, butanol can be burned "straight" in existing gasoline engines (without modification to the engine or car), produces more energy and is less corrosive and less water soluble than ethanol, and can be distributed via existing infrastructures.
  • Mixed alcohols are obtained by biomass-to-liquid technology or by bioconversion of biomass to mixed alcohol fuels. Commonly used are mixtures of ethanol, propanol, butanol, pentanol, hexanol, and heptanol, such as ecaleneTM.
  • GTL and BTL produce fuels from biomass in the so called Fischer Tropsch process. The synthetic biofuel containing oxygen is used as additive in high-quality diesel and petrol.

Gases

Biogas is produced by the process of anaerobic digestion of organic material by anaerobes. It can be produced either from biodegradable waste materials or by the use of energy crops fed into anaerobic digesters to supplement gas yields. The solid byproduct, digestate, can also be used as a biofuel.

Biogas contains methane and can be recovered in industrial anaerobic digesters and mechanical biological treatment systems. Landfill gas is a less clean form of biogas which is produced in landfills through naturally occurring anaerobic digestion. If it escapes into the atmosphere it is a potent greenhouse gas.

Oils and gases can be produced from various biological wastes:

Solids

Examples include wood, charcoal, and dried excrement.

Biomass in developing countries

Unfortunately, much cooking with biofuels is done indoors, with inefficient ventilation, and fuels such as dung cause airborne pollution. This can be a serious health hazard; 1.3 million deaths were attributed to this cause by the International Energy Agency in its World Energy Outlook 2006.

Proposed solutions include improved stoves (including those with inbuilt flues) and alternative fuels. But most of these have difficulties. One is that fuels are easily damaged. Another is that alternative fuels tend to be expensive, and people who use biofuels often do so precisely because they cannot afford alternatives.

Organizations such as Intermediate Technology Development Group work to make improved facilities for biofuel use and better alternatives accessible to those who cannot get them. This is done by improving ventilation, switching to different uses of biomass such as the creation of biogas from solid biomatter, or switching to other alternatives such as micro-hydro power.

Many environmentalists are concerned that first-growth forest may be felled in countries such as Indonesia to make way for palm oil plantations, driven by rising demand for diesel in SE Asia and Europe.

Direct biofuel

Direct biofuels are biofuels that can be used in existing unmodified petroleum engines. Because engine technology changes all the time, direct biofuel can be hard to define; a fuel that works well in one unmodified engine may not work in another. In general, newer engines are more sensitive to fuel than older engines, but new engines are also likely to be designed with some amount of biofuel in mind.

Straight vegetable oil can be used in some older diesel engines, but only in the warmest climates. Usually it is turned into biodiesel instead. No engine manufacturer explicitly allows any use of vegetable oil in their engines.

Biodiesel can be a direct biofuel. In some countries manufacturers cover many of their diesel engines under warranty for 100% biodiesel use, although Volkswagen Germany, for example, asks drivers to make a telephone check with the VW environmental services department before switching to 100% biodiesel (see biodiesel use). Many people have run thousands of miles on biodiesel without problem, and many studies have been made on 100% biodiesel. In many European countries, 100% biodiesel is widely used and is available at thousands of gas stations[3][4].

Butanol is often claimed as a direct replacement for gasoline. It is not in wide spread production at this time, and engine manufacturers have not made statements about its useTemplate:Verify source. While on paper (and a few lab tests) it appears that butanol has sufficiently similar characteristics with gasoline such that it should work without problem in any gasoline engine, no widespread experience exists.

Ethanol is the most common biofuel, and over the years many engines have been designed to run on it. Many of these could not run on regular gasoline, so it is debatable whether ethanol is a replacement in them. In the late 1990s, engines started appearing that by design can use either fuel. Ethanol is a direct replacement in these engines, but it is debatable if these engines are unmodified, or factory modified for ethanolTemplate:Verify source.

Small amounts of biofuel are often blended with traditional fuels. The biofuel portion of these fuels is a direct replacement for the fuel they offset, but the total offset is small. For biodiesel, 5% or 20% are commonly approved by various engine manufacturers[citation needed]||}}. See Common ethanol fuel mixtures for information on ethanol.

International efforts

Recognizing the importance of implementing bioenergy, there are international organizations such as IEA Bioenergy,<ref>http://www.ieabioenergy.com/IEABioenergy.php</ref> established in 1978 by the International Energy Agency (IEA), with the aim of improving cooperation and information exchange between countries that have national programs in bioenergy research, development and deployment.

European Union

Main article: biofuels directive

The European Union has set a goal:

Criticism

Rising food prices

Due to rising demand for biofuels, farmers in countries with limited agricultural potential are enticed to convert from production of food to production of raw material for biofuels. However, in the developing world, where a majority of people are farmers and where a vast mass of unused agricultural land exists, the biofuels opportunity may benefit millions of farmers and fuel economic development. If managed in a careless manner, the situation may lead to a rise in food prices, which may hurt others.

In early 2007 there were a number of reports linking stories as diverse as food riots in Mexico<ref>[Enrique C. Ochoa, The Costs of Rising Tortilla Prices in Mexico, February 3, 2007|http://www.zmag.org/content/showarticle.cfm?SectionID=59&ItemID=12030]</ref> due to rising prices of corn for tortillas and reduced profits at Heineken<ref>Financial Times, London, February 25 2007, quoting Jean-François van Boxmeer, chief executive</ref>, the large international brewer, to the increasing use of corn (maize) grown in the US Midwest for bio-ethanol production. (In the case of beer, it is more that barley acreage was cut to meet growing demand for corn, rather than the direct conversion of barley to ethanol, although the latter is technically possible.)

Energy efficiency of biodiesel

Production of biofuels from raw materials requires energy (for farming, transport and conversion to final product)and this varies greatly from one location to another. For example, in the US and Australia, farmers use much more oil to power their equipment than farmers in Brazil [citation needed]||}}. However, in some areas where forests are being thinned for forest fire fuels reduction projects, the production of the necessary biomass would occur whether or not a biomass industry existed. Therefore only the transport of the biomass from the field to a processing facility is a net energy cost. The costs of transporting wood chip have proven to be difficult to overcome.

Also studies on the energy balance of these fuels show large differences depending on the biomass feedstock used and location. [citation needed]||}}. Biofuels made from crops grown in temperate climates (such as corn or canola) have a relatively low energy efficiency[citation needed]||}}, whereas biofuels made from crops grown in the subtropics and the tropics (such as sugarcane, sweet sorghum, palm oil, cassava) show a very high energy efficiency[citation needed]||}}. For some biofuels (like ethanol made from corn) the energy balance may even be negative [citation needed]||}}.

Ecological impact

Biofuels offer one of the few options to substantially mitigate climate change. Since the effects of global warming can be devastating to world agriculture, the ecological impacts of growing biofuel crops may be small compared to the potentially much larger impacts of unmitigated climate change.

Since vast amounts of raw material are needed for biofuel production, monocultures and intensive farming may become more popular, which may cause environmental damages and undo some of the progress made towards sustainable agriculture. On the other hand, in the developing world poverty is the main cause of environmental destruction. If farmers in the developing world become energy farmers who sell biofuels on the international market, their incomes would increase substantially, and pressures on the environment would decrease. In this sense, the biofuels opportunity offers a way to lower the indirect impacts of poverty on the environment.

Energy content of biofuel

For a comprehensive chart of energy contents from different biofuels please see Energy content of Biofuel

  • Thermal depolymerization
  • Waste vegetable oil

See also

References

<references/>

  1. Biomass Technical Brief, Simon Ekless, Intermediate Technology Development Group, retrieved 1 January 2005 from http://www.itdg.org/docs/technical_information_service/biomass.pdf.
  2. Cellulosic Ethanol vs. Biomass Gasification, 22 October 2006, retrieved 19 November 2006 from http://i-r-squared.blogspot.com/2006/10/cellulosic-ethanol-vs-biomass.html
  3. Smoke — the killer in the kitchen, Intermediate Technology Development Group, 19 March 2004, retrieved 1 January 2005 from http://www.itdg.org/?id=smoke_report_1
  4. Reducing exposure to indoor air pollution, Intermediate Technology Development Group, 19 March 2004, retrieved 1 January 2005 from http://www.itdg.org/?id=smoke_report_3
  5. Biofuels Crop Index

External links

Template:Cleanup-spam


Further reading

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