biofuel is a fuel that is produced through such biological processes, such as agriculture and anaerobic digestion , rather than a fuel produced by geological processes such as those involved in the formation of fossil fuels , such as coal and petroleum, from prehistoric biological matter.

Biofuels can be derived directly from plants, or from agricultural, commercial, domestic, and / or industrial wastes. [1] Renewable biofuels generally involve contemporary carbon fixation , such as those that occur in plants or microalgae through the process of photosynthesis . Other renewable biofuels are made through the use or conversion of biomass (referring to recently living organisms, Most Often referring to plantsor plant-derived materials). This biomass can be converted to a suitable energy-containing substance in three different ways: thermal conversion, chemical conversion, and biochemical conversion. This biomass conversion can result in solid fuel , liquid , or gas form. This new biomass can also be used directly for biofuels.

Bioethanol is an alcohol made by fermentation , mostly from carbohydrates produced in sugar or starch crops such as corn , sugarcane , or sweet sorghum . Cellulosic biomass , derived from non-food sources, such as trees and grasses, is also being developed as a feedstock for ethanol production. Ethanol can be used as a fuel for vehicles in its pure form, but it is usually used as a gasoline additive to increase octane and improve vehicle emissions. Bioethanol is widely used in the United States andBrazil . Current plant design does not provide for converting the lignin portion of plant raw materials to fuel components by fermentation.

Biodiesel can be used as a fuel for vehicles in its pure form, but it is usually used as a diesel additive to reduce levels of particulates, carbon monoxide , and hydrocarbons from diesel-powered vehicles. Biodiesel is produced from oils or fats using transesterification and is the most common biofuel in Europe.

In 2010, worldwide biofuel production reached 105 billion liters (28 billion US gallons), up 17% from 2009, [2] and biofuels provided 2.7% of the world’s fuels for road transportation. Global ethanol fuel production reaches 86 billion liters (23 billion US gallons) in 2010, with the United States and Brazil as the world’s top producers, accounting for about 90% of global production. The world’s largest biodiesel producer is the European Union , accounting for 53% of all biodiesel production in 2010. [2] As of 2011, mandates for blending biofuels exist in 31 countries and 29 states or provinces. [3] The International Energy Agencyhas a goal for biofuels to meet more than 2050 to reduce dependence on petroleum and coal. [4] The production of biofuels also led to a flourishing automotive industry, where by 2010, 79% of all cars produced in Brazil were made with a hybrid fuel system of bioethanol and gasoline. [5]

There are various social, economic, environmental and technical issues relating to biofuels production and use, which have been debated in the popular media and scientific journals. These include: the effect of food prices , the ” food vs. fuel ” debate, poverty reduction potential, carbon emissions levels, sustainable biofuel production, deforestation and soil erosion, loss of biodiversity , impact on water resources , rural social exclusion and injustice, shantytown migration, rural unskilled unemployment, and nitrogen dioxide (NO 2 ) emissions.


First-generation biofuels

“First-generation” or biofuels are biofuels made from food grown on arable land. With this biofuel production generation, food crops are thus grown for fuel production , and not anything else. The sugar, starch, or vegetable oil is obtained from biodiesel or ethanol, using transesterification, or yeast fermentation. [6]

Second-generation biofuels

Main article: Second-generation biofuels

Second generation biofuels are produced from various types of biomass . Biomass is a wide-ranging term of any organic carbon that is renewed rapidly as part of the carbon cycle . Biomass is derived from plant materials, but can also include animal materials.

Whereas first generation biofuels are made from the sugars and vegetable oils found in arable crops, second generation biofuels are made from lignocellulosic biomass or woody crops, agricultural residues or waste plant material (from food crops). [7]

This has both advantages and disadvantages. The advantage is that, unlike regular food crops, no arable land is used solely for the production of fuel. The disadvantage is that it is difficult to extract fuel. For instance, a series of physical and chemical treatments may be required to convert lignocellulosic biomass to liquid fuels suitable for transportation. [8] [9]

Third-generation biofuels

Main articles: Algaculture and Algae fuel

From 1978 to 1996, the US NREL experimented with using a biofuels source in the ” Aquatic Species Program “. [10] A self-published article by Michael Briggs, at the UNH Biofuels Group, offers estimates for the real estate replacement of all vehicles with biofuels by using a natural gas content greater than 50%, which Briggs suggests can be grown it is algae ponds at wastewater treatment plants. [11]This oil-rich algae can then be extracted from the system and processed into biofuels, with the dried remainder further reprocessed to create ethanol. The production of algae has not yet been undertaken, but feasibility studies have been carried out. In addition to its high yield, algaculture – unlike crop-based biofuels – does not entail a decrease in food production , since it requires neither farmland nor fresh water . Many companies are pursuing various biofuels for various purposes, including scaling up biofuels production to commercial levels. [12] [13] Prof.Rodrigo E. Teixeira from the University of Alabama in Huntsville is demonstrating the extraction of lipid biofuels from wet algae using a simple and economical reaction in ionic liquids . [14]

Fourth-generation biofuels

Third-generation biofuels, fourth-generation biofuels are made using non-arable land. However, unlike third-generation biofuels, they do not require the destruction of biomass. This class of biofuels includes electrofuels [6]andphotobiological solar fuels. [15] Some of these fuels are carbon-neutral . The conversion of crude oil from the plant seeds is useful for cross- fertilization .


The following fuels can be produced using first, second, third or fourth generation biofuel production procedures. Most of these can be produced by two different types of biofuel generation procedures. [16]


Biologically produced alcohols , most commonly ethanol , and less commonly propanol and butanol , are produced by the action of microorganisms and enzymes through the fermentation of sugars or starches (easiest), or cellulose (which is more difficult). Biobutanol (also called biogasoline) is a direct replacement for gasoline, because it can be used directly in a gasoline engine.
US President George W. Bushlooks at sugar cane, a source of biofuel, with Brazilian President Luiz Inácio Lula da Silva during a biofuel technology tour at Petrobras in São Paulo , Brazil, March 9, 2007.

Ethanol fuel is the most common biofuel worldwide, particularly in Brazil . Alcohol fuels are produced by fermentation of sugars derived from wheat , corn , sugar beets , sugar cane , molasses and any sugar or starch from which alcoholic beverages such as whiskey , can be made (such as potatoand fruit waste, etc.). The ethanol production methods used to digest enzymes (to release sugars from starches), fermentation of the sugars, distillationand drying. The distillation process requires significant energy input for heat (sometimes unsustainable natural gas fossil fuel, but cellulosic biomass such as bagasse , the waste left after sugar cane is pressed to extract its juice, is the most common fuel in Brazil, while pellets, wood chips and steam waste fuels ethanol factory [17] – where waste heat from the factories is also used in the district heating grid.

Ethanol can be used in petrol engines as a replacement for gasoline; it can be mixed with gasoline to any percentage. Most existing petrol engines can run on blends of up to 15% bioethanol with petroleum / gasoline. Ethanol has a smaller energy density than that of gasoline; this means it takes more fuel (volume and mass) to produce the same amount of work. An advantage of ethanol ( CH
3 CH
2 OH ) is that it has a higher octane rating than ethanol-free gasoline available at roadside gas stations, which allows an increase in engine compression ratio for higher thermal efficiency.. In high-altitude (thin air) locations, some states mandate a mix of gasoline and ethanol as a winter oxidizer to reduce atmospheric pollution emissions.

Ethanol is also used to fuel bioethanol fireplaces . As they do not require a chimney and are “flueless”, bioethanol fires [18] are extremely useful for newly built homes and apartments without a flue. The downsides to these fireplaces is that their heat output is less than electric heat or gas fires, and must be avoided to avoid carbon monoxide poisoning.

Corn-to-ethanol and other food stocks have led to the development of cellulosic ethanol . According to the US Department of Energy, [19] the fossil energy ratios ( FER ) for cellulosic ethanol, ethanol, and gasoline are 10.3, 1.36, and 0.81, respectively. [20] [21] [22]

Ethanol has roughly one-third lower energy content per unit of volume compared to gasoline. This test is more likely to be effective when using ethanol (in a longer-term test of more than 2.1 million km, the best project found FFV vehicles to be 1-26% more efficient than petrol cars, but the volumetric consumption increases by approximately 30%, so more fuel stops are required).

With current subsidies, ethanol fuel is cheaper per distance traveled in the United States. quote needed ]


Main article: Biodiesel
Further information: Biodiesel around the world

Biodiesel is the most common biofuel in Europe. It is produced from oils or fats using transesterification and is a liquid similar in composition to fossil / mineral diesel. Chemically, it consists mostly of fatty acid methyl (or ethyl) esters ( FAMEs ). Feedstocks for biodiesel include animal fats, vegetable oils, soy , rapeseed , jatropha , mahua , mustard , flax , sunflower , palm oil , hemp , pennycress field , Pongamia pinnata and algae. Pure biodiesel (B100, also known as “neat” biodiesel). [23]

Biodiesel can be used in any diesel engine when mixed with mineral diesel. In some countries, manufacturers cover their diesel engines under warranty for B100 use, although Volkswagen of Germany , for example, asks for the VW checklist for environmental services before switching to B100. B100 may be more viscous at low temperatures, depending on the feedstock used. In most cases, biodiesel is compatible with diesel engines from 1994 onwards, which uses ‘ Viton ‘ (by DuPont ) synthetic rubber in their mechanical fuel injectionsystems. Note however, that no vehicles are certified for using pure biodiesel before 2014, as there was no emission control protocol available for biodiesel before this date.

Electronically controlled ‘ common rail ‘ and ‘ unit injector ‘ type systems from the late 1990s blended conventional biodiesel blended with diesel fuel oil. These engines have finely metered and atomized multiple-stage injection systems that are very sensitive to the viscosity of the fuel. Many current-generation diesel engines are made so That They Can we run B100 without altering the engine Itself, ALTHOUGH this depends on the fuel rail design. Since biodiesel is an effective solvent and cleans residues deposited by mineral diesel, the filters are often used in the fuel tank and pipes. It also effectively cleans the enginecombustion chamber of carbon deposits, helping to maintain efficiency. In many European countries, a 5% biodiesel blend is widely used and is available at thousands of gas stations. [24] [25] Biodiesel is also an oxygenated fuel , meaning it contains a reduced amount of carbon and a higher hydrogen content than fossil diesel. This improves the combustion of biodiesel and reduces particulate emissions from unburnt carbon. However, using pure biodiesel may increase NO x -emissions [26]

Biodiesel is also safe to handle because it is non-toxic and biodegradable , and has a high flash point of about 300 ° F (148 ° C) compared to petroleum diesel fuel, which has a flash point of 125 ° F (52 ° F). ° C). [27]

In the USA, more than 80% of commercial trucks and city buses run on diesel. The emerging US biodiesel market is estimated to have grown 200% from 2004 to 2005. “By the end of 2006 biodiesel production was estimated to increase fourfold [from 2004] to more than” 1 trillion US gallons (3,800,000 m 3 ). [28]

In France, biodiesel is incorporated at a rate of 8% in the fuel used by all French diesel vehicles. [29] Avril Group produces under the Diester brand , a fifth of 11 million tons of biodiesel consumed annually by the European Union . [30] It is the leading European producer of biodiesel. [29]

Other bioalcohols

Methanol is currently produced from natural gas , a non-renewable fossil fuel. In the future it is hoped to be produced from biomass as biomethanol . This is technically feasible, but the production is currently being postponed for the sake of Jacob S. Gibbs and Brinsley Coleberd that the economic viability is still pending. [31] The methanol economy is an alternative to the hydrogen economy , compared to today’s hydrogen production from natural gas.

Butanol ( C
4 H
9 OH ) is formed by ABE fermentation (acetone, butanol, ethanol) and experimental modifications of the process show potential high net energy gains with butanol as the only liquid product. Butanol will produce more energy and possibly be burned “straight” in existing gasoline engines, [32] and is less corrosive and less water-soluble than ethanol, and could be distributed via existing infrastructures. DuPont and BP are working together to help develop butanol. E. coliStrains have also been successfully engineered to produce butanol by modifying their amino acid metabolism . [33]

Green diesel

Main article: Vegetable oil refining

Green diesel is produced through hydrocracking biological oil feedstocks, such as vegetable oils and animal fats. [34] [35] Hydrocracking is a refinery That method uses elevated temperature and pressure in the presence of a catalyst to break down larger molecules , Such As Those found in vegetable oils , into go short hydrocarbon chains used in diesel engines. [36] It can also be called renewable diesel, hydrotreated vegetable oil [36] or hydrogen-derived renewable diesel. [35] Green diesel has the same chemical properties as petroleum-based diesel. [36]It does not require new engines, pipelines or infrastructure to distribute and use, but has not been produced at a cost that is competitive with petroleum . [35] Gasoline versions are also being developed. [37] Green diesel is being developed in Louisiana and Singapore by ConocoPhillips , Neste Oil , Valero , Dynamic Fuels, and Honeywell UOP [35] [38] and Preem in Gothenburg, Sweden, creating what is known as Evolution Diesel. [39]

Biofuel gasoline

In 2013 UK researchers developed a genetically modified strain of Escherichia coli ( E.Coli ), which could transform glucose into biofuel gasoline that does not need to be blended. [40] Later in 2013 UCLA researchers engineered a new metabolic pathway to bypass glycolysis and increase the rate of conversion of sugars into biofuel, [41] while KAIST researchers developed a strain of producing short-chain alkanes, free fatty acids, fatty esters and fatty alcohols through the fatty acyl (acyl carrier protein (ACP)) to fatty acid to fatty acyl-CoA pathway in vivo . [42] It is believed that in the future it will be possible to “tweak” the genes to make gasoline from straw or animal manure.

Vegetable oil

Walmart’s truck fleet has millions of miles each year, and the company is planning to double the fleet’s efficiency between 2005 and 2015. [43] This truck is one of 15 based at Walmart’s Buckeye, Arizona distribution center that was converted to run made from reclaimed cooking grease produced during food preparation at Walmart stores. [44]
Main article: Vegetable oil fuel

Straight unmodified edible vegetable oil has not been used as fuel but has been used for this purpose. Used vegetable oil is being processed into biodiesel, or (more rarely) cleaned of water and particulates and then used as a fuel.

As with 100% biodiesel (B100), to ensure the fuel injectors atomize the vegetable oil in the correct pattern for efficient combustion, vegetable oil fuel must be heated to reduce its viscosity to that of diesel, or by electric coils or heat exchangers. This is easier in warm or temperate climates. MAN B & W Diesel , Wärtsilä , and Deutz AG , such as Elsbett , are compatible with straight vegetable oil, without the need for after-market modifications.

Vegetable oil can be used in aussi Many older diesel engines That do not use common rail or unit injection diesel injection systems electronic. Due to the design of the combustion chambers in indirect injection engines, these are the best engines for use with vegetable oil. This system allows the more important molecules to burn more time to burn. Some older engines, especially Mercedes, are driven experimentally by enthusiasts without any conversion, a handful of drivers have experienced limited success with earlier pre- “Pumpe Duse” VW TDI engines and other similar engines with direct injection . Several companies, such as Elsbett Wolf, have developed professional conversion kits and successfully installed hundreds of them over the last decades.

Oils and fats can be hydrogenated to give a substitute diesel. The resulting product is a straight-chain hydrocarbon with a high cetane number , low in aromatics and sulfur and does not contain oxygen. Hydrogenated oils can be blended with diesel in all proportions. They have several advantages over biodiesel, including good performance at low temperatures and no susceptibility to microbial attack. [45]


Bioethers (also Referred to as fuel ethers or oxygenated fuels ) are cost-effective compounds That act as octane rating enhancers. “Bioethers are produced by the reaction of reactive iso-olefins, Such As iso-butylene, with bioethanol.” [46] Bioethers are created by wheat or sugar beet. [47] They also enhance engine performance, while significantly reducing engine wear and toxic exhaust emissions . The bioethers are likely to replace petroethers in the UK, it is highly unlikely they will become a fuel in the future. [48] Greatly reducing the amount of ground-levelozone emissions , they contribute to air quality. [49] [50]

When it comes to transportation fuel additive there are six ether: dimethyl ether (DME), diethyl ether (DEE), methyl teritiary-butyl ether (MTBE), ethyl ter -butyl ether (ETBE), t er -amyl methyl ether (TAME ), and ter- amyl ethyl ether (TAEE). [51]

The European Fuel Oxygenates Association (EFOA) credits methyl tertiary-butyl ether (MTBE) and ethyl tertiary-butyl ether (ETBE) as the most commonly used ethers in fuel to replace lead. Ethers were introduced in Europe in the 1970s to replace the highly toxic compound. [52] Although Europeans still use bio-ether additives, the US does not have an oxygen additive. [53]


Biogas is methane produced by the process of anaerobic digestion of organic materials by anaerobes . [54] It can be produced from biodegradable waste materials or by the use of energy crops fed into anaerobic digesters to supplement gas yields. The solid byproduct, digestate , can be used as a biofuel or a fertilizer.

Biogas can be recovered from mechanical biological treatment waste processing systems. Landfill gas , a cleaner form of biogas, is produced in landfills through naturally occurring anaerobic digestion. If it escapes into the atmosphere, it is a potential greenhouse gas .

Farmers can produce biogas from manure from their cattle by using anaerobic digesters. [55]


Main article: Gasification

Syngas , a mixture of carbon monoxide , hydrogen and other hydrocarbons, is produced by partial combustion of biomass, that is, combustion with an amount of oxygen that is not sufficient to convert the biomass completely to carbon dioxide and water. [45] Before partial combustion, the biomass is dried, and sometimes pyrolysed . The resulting gas mixture, syngas, is more efficient than direct combustion of the original biofuel; more of the energy contained in the fuel is extracted.

Syngas can be burned directly into internal combustion engines, or high-temperature fuel cell turbines . [56] The wood gas generator , a wood-fueled gasification reactor, can be connected to an internal combustion engine.

Syngas can be used to produce methanol , DME and hydrogen , or convert via the Fischer-Tropsch process to produce a diesel substitute, or a mixture of alcohols that can be blended into gasoline. Gasification normally at temperatures greater than 700 ° C.

Lower-temperature gasification is desirable when co-producing biochar , but results in syngas polluted with tar .

Solid biomass fuels

Examples include wood , sawdust , grass trimmings, domestic refuse , charcoal , agricultural waste , nonfood energy crops , and dried manure .

When solid biomass is already in a suitable form (such as firewood ), it can burn directly into a stove or provide heat or raise steam. When solid biomass is in an inconvenient form (such as sawdust, wood chips, grass, urban waste wood, agricultural residues), the typical process is to densify the biomass. This process includes grinding the raw biomass to an appropriate particle size (known as hogfuel), which, depending on the type densification, can be from 1 to 3 cm (0.4 to 1.2 in), which is then concentrated into a fuel product. The current processes produce wood pellets, cubes, gold pucks. The pellet process is most common in Europe, and is typically a pure wood product. The other types of densification are larger in size compared to a pellet and are compatible with a wide range of input feedstocks. The resulting densified fuel is easier to transport and feed into thermal generation systems, such as boilers.

Sawdust, bark and chips are already used for decades in industrial processes; examples include the pulp and paper industry and the sugar cane industry. Boilers in the range of 500,000 lb / hr of steam, and larger, are in routine operation, using grate, stoker spreader, suspension burning and fluid bed combustion. Utilities generate power, typically in the range of 5 to 50 MW, using locally available fuel. Other industries have also installed wood waste fuel boilers and dryers in areas with low-cost fuel. [57]

One of the advantages of solid biomass fuel is that byproduct, residue or product of other processes, such as farming, animal husbandry and forestry. [58] In theory, this means fuel and food production do not compete for resources, this is not always the case. [58]

A problem with the combustion of solid biomass fuels is that it has considerable amounts of pollutants , such as particulates and polycyclic aromatic hydrocarbons . Even modern pellet boilers generate much more pollutants than oil or natural gas boilers. Pellets made from agricultural residues are usually worse than wood pellets, producing much larger emissions of dioxins and chlorophenols . [59]

A derived fuel is biochar , which is produced by biomass pyrolysis . Biochar made from agricultural waste can substitute for wood charcoal. As wood is becoming scarce, this alternative is gaining ground. In eastern Democratic Republic of Congo , for example, biomass briquettes are being marketed as an alternative to charcoal to protect Virunga National Park from deforestation associated with charcoal production. [60]

By region

There are international organizations such as IEA Bioenergy, [61] established in 1978 by the OECD International Energy Agency (IEA), with the aim of improving cooperation and information exchange between national and national programs in bioenergy research, development and deployment. The UN International Biofuels Forum is formed by Brazil , China , India , Pakistan , South Africa , the United States and the European Commission . [62]The world leaders in biofuel development and use are Brazil, United States, France, Sweden and Germany. Russia also has 22% of world’s forest, [63] and is a big biomass (solid biofuels) supplier. In 2010, Russian pulp and paper maker, Vyborgskaya Cellulose, said they would be producing pellets that can be used in heat and electricity generation from its plant in Vyborg by the end of the year. [64] The plant will eventually produce 900,000 tons of pellets per year, making it the largest in the world.

Biofuels currently make up 3.1% [65] of the total road transport fuel in the UK or 1.440 million liters. By 2020, 10% of the energy used in the world is used to replace 4.3 million tonnes of fossil oil each year. Conventional biofuels are likely to produce between 3.7 and 6.6% of the energy needed in road transport and transportation, while advanced biofuels could meet up to 4.3% of the UK’s renewable transport fuel target by 2020. [66]

Air pollution

Main articles: Biomass § Environmental damage , and Ethanol_fuel § Air_pollution

Biofuels are different from fossil fuels in regard to greenhouse gases purpose are similar to fossil fuels biofuels fait que contribuer to air pollution . Burning produces airborne carbon particles , carbon monoxide and nitrous oxides . [67] The WHO estimates 3.7 million premature deaths worldwide in 2012 due to air pollution. [68] Brazil burns significant amounts of ethanol biofuel. Gas chromatograph studies were performed in São Paulo, Brazil, and compared to Osaka, Japan, which does not burn ethanol fuel. Atmospheric Formaldehyde was 160% higher in Brazil, and Acetaldehyde was 260% higher. [69]

Debates regarding the production and use of biofuel

Main article: Issues relating to biofuels

There are various social, economic, environmental and technical issues with biofuel production and use, which have been discussed in the popular media and scientific journals. These include: the effect of energy prices , the ” food vs. fuel ” debate, food prices , poverty reduction potential, energy ratio , energy requirements , carbon emissions levels, sustainable biofuel production, deforestation and soil erosion , loss of biodiversity , [70]. ] impact on water resourcesPossible modifications to the biofuel engine, as well as energy balance and efficiency. [71] The International Resource Panel , qui Provides independent scientific assessments and expert advice we have variety of resource-related topics, from the Assessed Relating to biofuel use in icts first postponement Towards sustainable generation and use of resources: Assessing Biofuels . [72]“Assessing Biofuels”, which is related to the subject of the study of biofuels. It concludes that it does not have the same impact on climate, energy security and ecosystems, and suggests that environmental and social impacts are needed throughout the life cycle.

Another issue with biofuel is the US has changed mandates many times because the production has been more than expected. The Renewable Fuel Standard (RFS) is a 100 million gallon of pure ethanol (not blended with a fossil fuel). [73]

Sustainable biofuels

Main article: Sustainable biofuels

Biofuels in the form of liquid fuels derived from plant materials are entering the market, driven by the perception that they reduce the climate of emissions, and also by factors such as oil prices and the need for increased energy security . However, many of the biofuels that have been supplied in 2008 have been criticized for their adverse impacts on the natural environment , food safety , and land use . [74] [75] In 2008, the Nobel-prize winning chemist Paul J. Crutzen published findings that the release of nitrous oxide (N2 O) emissions in the production of biofuels means that they contribute to global warming than the fossil fuels they replace. [76]

The challenge is to support biofuel development, including the development of new cellulosic technologies , with responsible policies and economic instruments to help ensure that biofuel commercialization is sustainable . Responsible commercialization of biofuels represents an opportunity to enhance sustainable economic prospects in Africa, Latin America and Asia. [74] [75] [77]

According to the Rocky Mountain Institute , sound biofuel production practices would not hamper food and fiber production, nor cause water or environmental problems, and would enhance soil fertility. [78] The selection of land is a critical component of the biofuels to deliver sustainable solutions. A key consideration is the minimization of biofuel competition for cropland premium. [79] [80]

Greenhouse gas emissions

Some scientists have been concerned about the use of biofuel and subsequent carbon emissions. [81] The payback period, which is, the time it will take to change the size of the country. land-use changes. However, no-till practices combined with cover-crop practices can reduce the conversion rate for 14 years for forest conversion. [82]

A study conducted in the Tocantis State, in northern Brazil, found that many families were cut by two plants, J. curcas (JC group) and R. communis (RC group). This region is composed of 15% Amazonian rainforest with high biodiversity, and 80% Cerrado forest with lower biodiversity. During the study, the farmers who planted the JC group released over 2193 Mg CO 2 , while losing 53-105 Mg CO 2 sequestration from deforestation; and the RC group farmers released 562 Mg CO 2 , while losing 48-90 Mg CO 2 to be sequestered from forest depletion. [83]The production of these types of biofuels not only leads to an increased emission of carbon dioxide, but also to the lower energy efficiency of these processes. This has to do with the amount of fossil fuel oil production. In addition, the intensive use of monocropping requires large amounts of water irrigation, as well as fertilizers, herbicides and pesticides. This product does not only lead to poisonous chemicals, but also to the emission of nitrous oxide (NO 2 ) as a fertilizer byproduct, which is more likely to produce carbon dioxide (CO 2 ) . [84]

Converting rainforests, peatlands, savannas, or grasslands to produce food crop-based biofuels in Brazil, Southeast Asia, and the United States creates a “biofuel carbon debt” by releasing 17 to 420 times more CO 2 than the annual greenhouse gas (GHG) that fossil fuels. Biofuels made from biomass waste from biomass grown on abandoned agricultural lands incur little to no carbon debt. [85]

Water Use

In addition to crop growth requires water, biofuel facilities require significant process water. [86]

Current research

Research is in progress in the field of biofuel crops and improving the yield of these crops. The current yields, vast amounts of land and fresh water would be needed to replace fossil fuel oil. It would require two-thirds of US production, or two-thirds to be devoted to production, to meet current US heating and transportation needs. quote needed ]

Specially bred mustard varieties can Produce reasonably high oil yields and are Very useful in crop rotation with cereals, and-have the added benefit que la meal left over after-the oil has-been pressed out can act as effective year and biodegradable pesticide. [87]

The NFESC , with Santa Barbara -based Biodiesel Industries, is working to develop biofuels technologies for the US navy and military, one of the largest diesel fuel users in the world. [88] A group of Spanish developers working for a company called Ecofasa announced a new biofuel made from trash. The fuel is created from general urban waste which is treated by bacteria to produce fatty acids, which can be used to make biofuels. [89] Before its shutdown, Joule Unlimited is attempting to make ethanol and biodiesel from a genetically modified photosynthetic bacterium.

Ethanol biofuels (bioethanol)

Main articles: Ethanol fuel and Cellulosic ethanol commercialization

As the primary source of biofuels in North America, many organizations are conducting research in the area of ethanol production. The National Corn-to-Ethanol Research Center (NCERC) is a research division of Southern Illinois Edwardsville University dedicated solely to ethanol-based biofuel research projects. [90] On the federal level, the USDA conducts a large amount of research regarding ethanol production in the United States. Much of this research is aimed at the effect of ethanol production on domestic food markets. [91] A division of the US Department of Energy , the National Renewable Energy Laboratory (NREL), has also conducted various ethanol research projects, mainly in the area of ​​cellulosic ethanol. [92]

Cellulosic ethanol commercialization is the process of building an industry out of methods of turning cellulose-containing organic matter into fuel. Companies, such as Iogen , POET , and Abengoa , are building refineries that can process biomass and turn it into bioethanol . Companies, such as Diversa , Novozymes , and Dyadic , are producing enzymes that could enable future cellulosic ethanol . The shift from food crop to farmer’s share of the market, from farmers to biotechnology firms, and from project developers to investors.[93]

As of 2013, the first commercially-grown seedlings to produce cellulosic biofuels have been operating. Multiple pathways for the conversion of different biofuel feedstocks are being used. In the next few years, the cost data of these technologies operating at commercial scale, and their relative performance, will become available. Lessons will learn the costs of the industrial processes involved. [94]

In parts of Asia and Africa where drylands prevail, sweet sorghum is being investigated as a potential source of food, feed and fuel combined. The crop is particularly suitable for growing in arid conditions, as it is one of the extracts of water used by sugarcane. In India , and other places, sweet sorghum stalks are used to produce biofuel by squeezing the juice and then fermenting into ethanol . [95]

A study by researchers at the International Crops Research Institute for the Semi-Arid Tropics ( ICRISAT ) found that growing sweet sorghum instead of grain sorghum could increase farmers incomes by US $ 40 per hectare per crop because it can provide fuel in addition to food and animal feed. With grain sorghum currently grown over 11 million hectares in Asia and 23.4 million hectares in Africa, a switch to sweet sorghum could have a considerable economic impact. [96]


Main article: Jatropha biofuel

Several groups are in various Sectors Conducting research is Jatropha curcas , a poisonous shrub-like tree That Produces seeds regarded by many to be a viable source of biofuel feedstock oil. [97] Much of this research focuses on improving the overall performance of Jatropha through advancements in genetics, soil science, and horticultural practices.

SG Biofuels , a San Diego-based jatropha developer, has used molecular breeding and biotechnology to produce elite hybrid seeds that show significant yield improvements over first-generation varieties. [98] SG Biofuels also claims additional benefits to such strains, including improved flowering synchronicity, higher resistance to pests and diseases, and increased cold-weather tolerance. [99]

Plant Research International, a department of the Wageningen University and Research Center in the Netherlands, maintains an ongoing Jatropha Evaluation Project that examines the feasibility of large-scale jatropha cultivation through field and laboratory experiments. [100] The Center for Sustainable Energy Farming (CfSEF) is a Los Angeles-based nonprofit research organization dedicated to jatropha research in the areas of plant science, agronomy, and horticulture. Successful exploration of these disciplines is projected to increase production by 200-300% in the next 10 years. [101]


A group at the Russian Academy of Sciences in Moscow , published in 2008, published in English, published in the English version of the article. More research on this fungal species, Cunninghamella japonica , and others, is likely to appear in the near future. [102] The recent discovery of a variant of the fungus Gliocladium roseum (later renamed Ascocoryne sarcoides) dots Toward the generation of so-called myco-diesel from cellulose. This organism was recently discovered in the rainforests of northern Patagonia, and has the unique capability of converting cellulose into medium-length hydrocarbons typically found in diesel fuel. [103] Many other fungi that can degrade cellulose and other polymers that are currently being engineered, in [104] ).

Animal gut bacteria

Microbial gastrointestinal flora in a variety of animals has shown potential for the production of biofuels. TU-103, a strain of Clostridium Bacteria Found in Zebra feces, can be found in the form of butanol fuel. [105] Microbes in panda are being investigated for their use in biofuels from bamboo and other plant materials. [106] There has been substantial research into the use of microbiota of wood-feeding insects for the conversion of lignocellulose material into biofuel. [107]