A bus fueled by biodiesel

Information on pump regarding ethanolfuel blend up to 10%, California

BiofuelFrom Wikipedia, the free encyclopedia

A biofuel is a fuel that contains energy from geologically recentcarbon fixation. These fuels are produced from living organisms.Examples of this carbon fixation occur in plants and microalgae.These fuels are made by a biomass conversion (biomass refers torecently living organisms, most often referring to plants or plant-derived materials). This biomass can be converted to convenientenergy containing substances in three different ways: thermalconversion, chemical conversion, and biochemical conversion. Thisbiomass conversion can result in fuel in solid, liquid, or gas form.This new biomass can be used for biofuels. Biofuels have increasedin popularity because of rising oil prices and the need for energysecurity. However, according to the European Environment Agency,biofuels do not necessarily mitigate global warming.[1]

Bioethanol is an alcohol made by fermentation, mostly fromcarbohydrates produced in sugar or starch crops such as corn orsugarcane. Cellulosic biomass, derived from non-food sources, suchas trees and grasses, is also being developed as a feedstock forethanol production. Ethanol can be used as a fuel for vehicles in itspure form, but it is usually used as a gasoline additive to increaseoctane and improve vehicle emissions. Bioethanol is widely used inthe USA and in Brazil. Current plant design does not provide forconverting the lignin portion of plant raw materials to fuelcomponents by fermentation.

Biodiesel is made from vegetable oils and animal fats. 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 fromdiesel-powered vehicles. Biodiesel is produced from oils or fats using transesterification and is the most commonbiofuel in Europe.

In 2010, worldwide biofuel production reached 105 billion liters (28 billion gallons US), up 17% from 2009,[2] andbiofuels provided 2.7% of the world's fuels for road transport, a contribution largely made up of ethanol andbiodiesel.[citation needed] Global ethanol fuel production reached 86 billion liters (23 billion gallons US) in 2010,with the United States and Brazil as the world's top producers, accounting together for 90% of global production.The world's largest biodiesel producer is the European Union, accounting for 53% of all biodiesel production in2010.[2] As of 2011, mandates for blending biofuels exist in 31 countries at the national level and in 29 states orprovinces.[3] The International Energy Agency has a goal for biofuels to meet more than a quarter of world demandfor transportation fuels by 2050 to reduce dependence on petroleum and coal.[4]

Contents1 Liquid fuels for transportation

1.1 First-generation biofuels1.1.1 Bioalcohols1.1.2 Biodiesel1.1.3 Green diesel1.1.4 Biofuel gasoline1.1.5 Vegetable oil1.1.6 Bioethers1.1.7 Biogas1.1.8 Syngas1.1.9 Solid biofuels

1.2 Second-generation (advanced) biofuels2 Biofuels by region3 Issues with biofuel production and use4 Current research

4.1 Ethanol biofuels4.2 Algae biofuels4.3 Jatropha4.4 Fungi4.5 Animal Gut Bacteria

5 Greenhouse gas emissions6 See also7 References8 Further reading9 External links

Liquid fuels for transportationMost transportation fuels are liquids, because vehicles usually require high energy density, as occurs in liquids andsolids. High power density can be provided most inexpensively by an internal combustion engine; these enginesrequire clean-burning fuels, to keep the engine clean and minimize air pollution.

The fuels that are easiest to burn cleanly are typically liquids and gases. Thus, liquids (and gases that can be storedin liquid form) meet the requirements of being both portable and clean-burning. Also, liquids and gases can bepumped, which means handling is easily mechanized, and thus less laborious.

First-generation biofuels

'First-generation' or conventional biofuels are made from sugar, starch, or vegetable oil.

Bioalcohols

Main article: Alcohol fuel

Neat ethanol on the left (A), gasolineon the right (G) at a filling station inBrazil

Biologically produced alcohols, most commonly ethanol, and lesscommonly propanol and butanol, are produced by the action ofmicroorganisms and enzymes through the fermentation of sugars orstarches (easiest), or cellulose (which is more difficult). Biobutanol (alsocalled biogasoline) is often claimed to provide a direct replacement forgasoline, because it can be used directly in a gasoline engine (in a similarway to biodiesel in diesel engines).

Ethanol fuel is the most common biofuel worldwide, particularly in Brazil.Alcohol fuels are produced by fermentation of sugars derived fromwheat, corn, sugar beets, sugar cane, molasses and any sugar or starchfrom which alcoholic beverages can be made (such as potato and fruitwaste, etc.). The ethanol production methods used are enzyme digestion(to release sugars from stored starches), fermentation of the sugars,

distillation and drying. The distillation process requires significant energy input for heat (often unsustainable naturalgas fossil fuel, but cellulosic biomass such as bagasse, the waste left after sugar cane is pressed to extract its juice,can also be used more sustainably).

Ethanol can be used in petrol engines as a replacement for gasoline; it can be mixed with gasoline to anypercentage. Most existing car 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) toproduce the same amount of work. An advantage of ethanol (CH3CH2OH) is that it has a higher octane rating thanethanol-free gasoline available at roadside gas stations, which allows an increase of an engine's compression ratiofor increased thermal efficiency. In high-altitude (thin air) locations, some states mandate a mix of gasoline andethanol 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", bioethanolfires[5] are extremely useful for newly built homes and apartments without a flue. The downsides to these fireplacesis that their heat output is slightly less than electric heat or gas fires, and precautions must be taken to avoid carbonmonoxide poisoning.

In the current corn-to-ethanol production model in the United States, considering the total energy consumed byfarm equipment, cultivation, planting, fertilizers, pesticides, herbicides, and fungicides made from petroleum,irrigation systems, harvesting, transport of feedstock to processing plants, fermentation, distillation, drying, transportto fuel terminals and retail pumps, and lower ethanol fuel energy content, the net energy content value added anddelivered to consumers is very small. And, the net benefit (all things considered) does little to reduce imported oiland fossil fuels required to produce the ethanol.[6]

Although corn-to-ethanol and other food stocks have implications both in terms of world food prices and limited,yet positive, energy yield (in terms of energy delivered to customer/fossil fuels used), the technology has led to thedevelopment of cellulosic ethanol. According to a joint research agenda conducted through the US Department ofEnergy,[7] the fossil energy ratios (FER) for cellulosic ethanol, corn ethanol, and gasoline are 10.3, 1.36, and 0.81,respectively.[8][9][10]

Even dry ethanol has roughly one-third lower energy content per unit of volume compared to gasoline, so larger(therefore heavier) fuel tanks are required to travel the same distance, or more fuel stops are required. With largecurrent unsustainable, unscalable subsidies, ethanol fuel still costs more per distance traveled than current highgasoline prices in the United States.[11]

In some countries, biodiesel is lessexpensive than conventional diesel.

Methanol is currently produced from natural gas, a nonrenewable fossil fuel. It can also be produced from biomassas biomethanol. The methanol economy is an alternative to the hydrogen economy, compared to today's hydrogenproduction from natural gas.

Butanol (C4H9OH) is formed by ABE fermentation (acetone, butanol, ethanol) and experimental modifications ofthe process show potentially high net energy gains with butanol as the only liquid product. Butanol will producemore energy and allegedly can be burned "straight" in existing gasoline engines (without modification to the engine orcar),[12] and is less corrosive and less water-soluble than ethanol, and could be distributed via existinginfrastructures. DuPont and BP are working together to help develop butanol. E. coli strains have also beensuccessfully engineered to produce butanol by hijacking their amino acid metabolism.[13]

Biodiesel

Main articles: Biodiesel and Biodiesel around the world

Biodiesel is the most common biofuel in Europe. It is produced from oilsor fats using transesterification and is a liquid similar in composition tofossil/mineral diesel. Chemically, it consists mostly of fatty acid methyl (orethyl) esters (FAMEs). Feedstocks for biodiesel include animal fats,vegetable oils, soy, rapeseed, jatropha, mahua, mustard, flax, sunflower,palm oil, hemp, field pennycress, Pongamia pinnata and algae. Purebiodiesel (B100) is the lowest-emission diesel fuel. Although liquefiedpetroleum gas and hydrogen have cleaner combustion, they are used tofuel much less efficient petrol engines and are not as widely available.

Biodiesel can be used in any diesel engine when mixed with mineraldiesel. In some countries, manufacturers cover their diesel engines underwarranty for B100 use, although Volkswagen of Germany, for example,asks drivers to check by telephone with the VW environmental servicesdepartment before switching to B100. B100 may become more viscousat lower temperatures, depending on the feedstock used. In most cases,biodiesel is compatible with diesel engines from 1994 onwards, whichuse 'Viton' (by DuPont) synthetic rubber in their mechanical fuel injectionsystems.

Electronically controlled 'common rail' and 'unit injector' type systemsfrom the late 1990s onwards may only use biodiesel blended withconventional diesel fuel. These engines have finely metered and atomized multiple-stage injection systems that arevery sensitive to the viscosity of the fuel. Many current-generation diesel engines are made so that they can run onB100 without altering the engine itself, although this depends on the fuel rail design. Since biodiesel is an effectivesolvent and cleans residues deposited by mineral diesel, engine filters may need to be replaced more often, as thebiofuel dissolves old deposits in the fuel tank and pipes. It also effectively cleans the engine combustion chamber ofcarbon deposits, helping to maintain efficiency. In many European countries, a 5% biodiesel blend is widely usedand is available at thousands of gas stations.[14][15] Biodiesel is also an oxygenated fuel, meaning it contains areduced amount of carbon and higher hydrogen and oxygen content than fossil diesel. This improves thecombustion of biodiesel and reduces the particulate emissions from unburnt carbon.

Biodiesel is also safe to handle and transport because it is as biodegradable as sugar, one-tenth as toxic as tablesalt, and has a high flash point of about 300°F (148°C) compared to petroleum diesel fuel, which has a flash pointof 125°F (52°C).[16]

In the USA, more than 80% of commercial trucks and city buses run on diesel. The emerging US biodiesel marketis estimated to have grown 200% from 2004 to 2005. "By the end of 2006 biodiesel production was estimated toincrease fourfold [from 2004] to more than" 1 billion US gallons (3,800,000 m3).[17]

Green diesel

Main article: Vegetable oil refining

Green diesel is produced through hydrocracking biological oil feedstocks, such as vegetable oils and animalfats.[18][19] Hydrocracking is a refinery method that uses elevated temperatures and pressure in the presence of acatalyst to break down larger molecules, such as those found in vegetable oils, into shorter hydrocarbon chainsused in diesel engines.[20] It may also be called renewable diesel, hydrotreated vegetable oil[20] or hydrogen-derived renewable diesel.[19] Green diesel has the same chemical properties as petroleum-based diesel.[20] It doesnot require new engines, pipelines or infrastructure to distribute and use, but has not been produced at a cost that iscompetitive with petroleum.[19] Gasoline versions are also being developed.[21] Green diesel is being developed inLouisiana and Singapore by ConocoPhillips, Neste Oil, Valero, Dynamic Fuels, and Honeywell UOP.[19][22]

Biofuel gasoline

In 2013 UK researchers developed a genetically modified strain of Escherichia coli which could transform glucoseinto biofuel gasoline that does not need to be blended.[23] Later in 2013 UCLA researchers engineered a newmetabolic pathway to bypass glycolysis and increase the rate of conversion of sugars into biofuel,[24] while KAISTresearchers developed a strain capable of producing short-chain alkanes, free fatty acids, fatty esters and fattyalcohols through the fatty acyl (acyl carrier protein (ACP)) to fatty acid to fatty acyl-CoA pathway in vivo.[25] It isbelieved that in the future it will be possible to "tweak" the genes to make gasoline from straw or animal manure.

Vegetable oil

Main article: Vegetable oil used as fuel

Straight unmodified edible vegetable oil is generally not used as fuel, but lower-quality oil can and has been used forthis purpose. Used vegetable oil is increasingly being processed into biodiesel, or (more rarely) cleaned of waterand particulates and used as a fuel.

Also here, as with 100% biodiesel (B100), to ensure the fuel injectors atomize the vegetable oil in the correctpattern for efficient combustion, vegetable oil fuel must be heated to reduce its viscosity to that of diesel, either byelectric coils or heat exchangers. This is easier in warm or temperate climates. Big corporations like MAN B&WDiesel, Wärtsilä, and Deutz AG, as well as a number of smaller companies, such as Elsbett, offer engines that arecompatible with straight vegetable oil, without the need for after-market modifications.

Vegetable oil can also be used in many older diesel engines that do not use common rail or unit injection electronicdiesel injection systems. Due to the design of the combustion chambers in indirect injection engines, these are thebest engines for use with vegetable oil. This system allows the relatively larger oil molecules more time to burn.

Filtered waste vegetable oil

Some older engines, especially Mercedes, are driven experimentally by enthusiasts without any conversion, ahandful of drivers have experienced limited success with earlier pre-"Pumpe Duse" VW TDI engines and othersimilar engines with direct injection. Several companies, such as Elsbett or Wolf, have developed professionalconversion kits and successfully installed hundreds of them over the last decades.

Oils and fats can be hydrogenated to give a diesel substitute. The resulting product is a straight-chain hydrocarbonwith a high cetane number, low in aromatics and sulfur and does not contain oxygen. Hydrogenated oils can beblended with diesel in all proportions. They have several advantages over biodiesel, including good performance atlow temperatures, no storage stability problems and no susceptibility to microbial attack.[26]

Bioethers

Bioethers (also referred to as fuel ethers or oxygenated fuels) are cost-effective compounds that act as octanerating enhancers. They also enhance engine performance, whilst significantlyreducing engine wear and toxic exhaust emissions. Greatly reducing the amount ofground-level ozone, they contribute to air quality.[27][28]

Biogas

Main article: Biogas

Biogas is methane produced by the process of anaerobic digestion of organicmaterial by anaerobes.[29] It can be produced either from biodegradable wastematerials or by the use of energy crops fed into anaerobic digesters to supplementgas yields. The solid byproduct, digestate, can be used as a biofuel or a fertilizer.

Biogas can be recovered from mechanical biological treatment wasteprocessing systems.

Note: Landfill gas, a less clean form of biogas, is produced in landfillsthrough naturally occurring anaerobic digestion. If it escapes into theatmosphere, it is a potential greenhouse gas.

Farmers can produce biogas from manure from their cattle by usinganaerobic digesters.[30]

Syngas

Main article: Gasification

Syngas, a mixture of carbon monoxide, hydrogen and other hydrocarbons, is produced by partial combustion ofbiomass, that is, combustion with an amount of oxygen that is not sufficient to convert the biomass completely tocarbon dioxide and water.[26] Before partial combustion, the biomass is dried, and sometimes pyrolysed. Theresulting gas mixture, syngas, is more efficient than direct combustion of the original biofuel; more of the energycontained in the fuel is extracted.

Syngas may be burned directly in internal combustion engines, turbines or high-temperature fuel cells.[31] The

Pipes carrying biogas

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 converted via the Fischer-Tropschprocess to produce a diesel substitute, or a mixture of alcohols that can be blended into gasoline. Gasificationnormally relies on temperatures greater than 700°C.Lower-temperature gasification is desirable when co-producing biochar, but results in syngas polluted withtar.

Solid biofuels

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

When raw biomass is already in a suitable form (such as firewood), it can burndirectly in a stove or furnace to provide heat or raise steam. When raw biomass is inan inconvenient form (such as sawdust, wood chips, grass, urban waste wood,agricultural residues), the typical process is to densify the biomass. This processincludes grinding the raw biomass to an appropriate particulate size (known ashogfuel), which, depending on the densification type, can be from 1 to 3 cm(0 to 1 in), which is then concentrated into a fuel product. The current processesproduce wood pellets, cubes, or pucks. The pellet process is most common inEurope, and is typically a pure wood product. The other types of densification arelarger in size compared to a pellet, and are compatible with a broad range of inputfeedstocks. The resulting densified fuel is easier to transport and feed into thermal generation systems, such asboilers.

Industry has used sawdust, bark and chips for fuel for decades, primary in the pulp and paper industry, and alsobagasse (spent sugar cane) fueled boilers in the sugar cane industry. Boilers in the range of 500,000 lb/hr of steam,and larger, are in routine operation, using grate, spreader stoker, 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 alsoinstalled wood waste fueled boilers and dryers in areas with low cost fuel.[32]

One of the advantages of solid biomass fuel is that it is often a byproduct, residue or waste-product of otherprocesses, such as farming, animal husbandry and forestry.[33] In theory, this means fuel and food production donot compete for resources, although this is not always the case.[33]

A problem with the combustion of raw biomass is that it emits considerable amounts of pollutants, such asparticulates and polycyclic aromatic hydrocarbons. Even modern pellet boilers generate much more pollutants thanoil or natural gas boilers. Pellets made from agricultural residues are usually worse than wood pellets, producingmuch larger emissions of dioxins and chlorophenols.[34]

Notwithstanding the above noted study, numerous studies have shown biomass fuels have significantly less impacton the environment than fossil based fuels. Of note is the US Department of Energy Laboratory, operated byMidwest Research Institute Biomass Power and Conventional Fossil Systems with and without CO2 Sequestration– Comparing the Energy Balance, Greenhouse Gas Emissions and Economics Study. Power generation emitssignificant amounts of greenhouse gases (GHGs), mainly carbon dioxide (CO2). Sequestering CO2 from the power

plant flue gas can significantly reduce the GHGs from the power plant itself, but this is not the total picture. CO2capture and sequestration consumes additional energy, thus lowering the plant's fuel-to-electricity efficiency. Tocompensate for this, more fossil fuel must be procured and consumed to make up for lost capacity.

Taking this into consideration, the global warming potential (GWP), which is a combination of CO2, methane(CH4), and nitrous oxide (N2O) emissions, and energy balance of the system need to be examined using a life cycleassessment. This takes into account the upstream processes which remain constant after CO2 sequestration, as wellas the steps required for additional power generation. Firing biomass instead of coal led to a 148% reduction inGWP.

A derivative of solid biofuel is biochar, which is produced by biomass pyrolysis. Biochar made from agriculturalwaste can substitute for wood charcoal. As wood stock becomes scarce, this alternative is gaining ground. Ineastern Democratic Republic of Congo, for example, biomass briquettes are being marketed as an alternative tocharcoal to protect Virunga National Park from deforestation associated with charcoal production.[35]

Second-generation (advanced) biofuels

Main article: Second-generation biofuels

Second-generation biofuels are produced from sustainable feedstock. Sustainability of a feedstock is defined,among others, by availability of the feedstock, impact on GHG emissions, and impact on biodiversity and landuse.[36] Many second-generation biofuels are under development such as Cellulosic ethanol, Algae fuel,[37]

biohydrogen, biomethanol, DMF, BioDME, Fischer-Tropsch diesel, biohydrogen diesel, mixed alcohols and wooddiesel.

Cellulosic ethanol production uses nonfood crops or inedible waste products and does not divert food away fromthe animal or human food chain. Lignocellulose is the "woody" structural material of plants. This feedstock isabundant and diverse, and in some cases (like citrus peels or sawdust) it is in itself a significant disposal problem.

Producing ethanol from cellulose is a difficult technical problem to solve. In nature, ruminant livestock (such ascattle) eat grass and then use slow enzymatic digestive processes to break it into glucose (sugar). In cellulosicethanol laboratories, various experimental processes are being developed to do the same thing, and then the sugarsreleased can be fermented to make ethanol fuel. In 2009, scientists reported developing, using "synthetic biology","15 new highly stable fungal enzyme catalysts that efficiently break down cellulose into sugars at high temperatures",adding to the 10 previously known.[38] The use of high temperatures has been identified as an important factor inimproving the overall economic feasibility of the biofuel industry and the identification of enzymes that are stable andcan operate efficiently at extreme temperatures is an area of active research.[39] In addition, research conducted atDelft University of Technology by Jack Pronk has shown that elephant yeast, when slightly modified, can alsoproduce ethanol from inedible ground sources (e.g. straw).[40][41]

The recent discovery of the fungus Gliocladium roseum points toward the production of so-called myco-dieselfrom cellulose. This organism (recently discovered in rainforests of northern Patagonia) has the unique capability ofconverting cellulose into medium-length hydrocarbons typically found in diesel fuel.[42] Scientists also work onexperimental recombinant DNA genetic engineering organisms that could increase biofuel potential.

Scientists working with the New Zealand company Lanzatech have developed a technology to use industrial wastegases, such as carbon monoxide from steel mills, as a feedstock for a microbial fermentation process to produceethanol.[43][44] In October 2011, Virgin Atlantic announced it was joining with Lanzatech to commission ademonstration plant in Shanghai that would produce an aviation fuel from waste gases from steel production.[45]

Scientists working in Minnesota have developed co-cultures of Shewanella and Synechococcus that producelong-chain hydrocarbons directly from water, carbon dioxide, and sunlight.[46] The technology has received ARPA-E funding.

Biofuels by regionMain article: Biofuels by region

See also: Biodiesel around the world

There are international organizations such as IEA Bioenergy,[47] established in 1978 by the OECD InternationalEnergy Agency (IEA), with the aim of improving cooperation and information exchange between countries thathave national programs in bioenergy research, development and deployment. The UN International Biofuels Forumis formed by Brazil, China, India, Pakistan, South Africa, the United States and the European Commission.[48] Theworld leaders in biofuel development and use are Brazil, the United States, France, Sweden and Germany. Russiaalso has 22% of world's forest,[49] and is a big biomass (solid biofuels) supplier. In 2010, Russian pulp and papermaker, Vyborgskaya Cellulose, said they would be producing pellets that can be used in heat and electricitygeneration from its plant in Vyborg by the end of the year.[50] The plant will eventually produce about 900,000 tonsof pellets per year, making it the largest in the world once operational.

Biofuels currently make up 3.1%[51] of the total road transport fuel in the UK or 1,440 million litres. By 2020, 10%of the energy used in UK road and rail transport must come from renewable sources – this is the equivalent ofreplacing 4.3 million tonnes of fossil oil each year. Conventional biofuels are likely to produce between 3.7 and6.6% of the energy needed in road and rail transport, while advanced biofuels could meet up to 4.3% of the UK’srenewable transport fuel target by 2020.[52]

Issues with biofuel production and useMain article: Issues relating to biofuels

There are various social, economic, environmental and technical issues with biofuel production and use, which havebeen discussed in the popular media and scientific journals. These include: the effect of moderating oil prices, the"food vs fuel" debate, effects on poverty, carbon emissions levels, sustainable biofuel production, deforestation andsoil erosion, loss of biodiversity, and impact on water resources, as well as energy balance and efficiency. TheInternational Resource Panel, which provides independent scientific assessments and expert advice on a variety ofresource-related themes, assessed the issues relating to biofuel use in its first report, Towards sustainableproduction and use of resources: Assessing Biofuels.[53] The report outlined the wider and interrelated factorsthat need to be considered when deciding on the relative merits of pursuing one biofuel over another. It concludednot all biofuels perform equally in terms of their impact on climate, energy security, and ecosystems, and suggestedenvironmental and social impacts need to be assessed throughout the entire life-cycle. The pros and cons ofbiomass usage regarding carbon emissions are summed up in the ILUC factor. The biomass industry has beentrying to avoid or delay the usage of the ILUC factor.[54]

Although many current issues are noted with biofuel production and use, the development of new biofuel crops andsecond-generation biofuels attempts to circumvent these issues. Many scientists and researchers are working todevelop biofuel crops that require less land and use fewer resources, such as water, than current biofuel crops do.According to the journal Renewable fuels from algae: An answer to debatable land based fuels,[55] algae are asource for biofuels that could use currently unprofitable land and wastewater from different industries. Algae areable to grow in wastewater, which does not affect the land or freshwater needed to produce current food and fuelcrops. Furthermore, algae are not part of the human food chain, so do not take away food resources from humans.

The effects of the biofuel industry on food are still being debated. According to a recent study,[56] biofuelproduction accounted for 3-30% of the increase in food prices in 2008. A recent study for the International Centrefor Trade and Sustainable Development shows market-driven expansion of ethanol in the US increased corn pricesby 21% in 2009, in comparison with what prices would have been had ethanol production been frozen at 2004levels.[57] This has prompted researchers to develop biofuel crops and technologies that will reduce the impact ofthe growing biofuel industry on food production and cost.

One step to overcoming these issues is developing biofuel crops best suited to each region of the world. If eachregion used a specific biofuel crop, the need to use fossil fuels to transport the fuel to other places for processingand consumption would be diminished. Furthermore, certain areas of the globe are unsuitable for producing cropsthat require large amounts of water and nutrient-rich soil. Therefore current biofuel crops, such as corn, areimpractical in certain environments and regions of the globe.

In 2012, the United States House Committee on Armed Services put language into the 2013 National DefenseAuthorization Act that would prevent the Pentagon from purchasing biofuels that offered improved performance forcombat aircraft.[58]

Current researchResearch is ongoing into finding more suitable biofuel crops and improving the oil yields of these crops. Using thecurrent yields, vast amounts of land and fresh water would be needed to produce enough oil to completely replacefossil fuel usage. It would require twice the land area of the US to be devoted to soybean production, or two-thirdsto be devoted to rapeseed production, to meet current US heating and transportation needs.[citation needed]

Specially bred mustard varieties can produce reasonably high oil yields and are very useful in crop rotation withcereals, and have the added benefit that the meal left over after the oil has been pressed out can act as an effectiveand biodegradable pesticide.[59]

The NFESC, with Santa Barbara-based Biodiesel Industries, is working to develop biofuels technologies for theUS navy and military, one of the largest diesel fuel users in the world.[60] A group of Spanish developers workingfor a company called Ecofasa announced a new biofuel made from trash. The fuel is created from general urbanwaste which is treated by bacteria to produce fatty acids, which can be used to make biofuels.[61]

Ethanol biofuels

Main Article Ethanol Fuels

As the primary source of biofuels in North America, many organizations are conducting research in the area ofethanol production. The National Corn-to-Ethanol Research Center (NCERC) is a research division of SouthernIllinois University Edwardsville dedicated solely to ethanol-based biofuel research projects.[62] On the federal level,the USDA conducts a large amount of research regarding ethanol production in the United States. Much of thisresearch is targeted toward the effect of ethanol production on domestic food markets.[63] A division of the U.S.Department of Energy, the National Renewable Energy Laboratory (NREL), has also conducted various ethanolresearch projects, mainly in the area of cellulosic ethanol.[64]

Algae biofuels

Main articles: Algaculture and Algal fuel

From 1978 to 1996, the US NREL experimented with using algae as a biofuels source in the "Aquatic SpeciesProgram".[65] A self-published article by Michael Briggs, at the UNH Biofuels Group, offers estimates for therealistic replacement of all vehicular fuel with biofuels by using algae that have a natural oil content greater than50%, which Briggs suggests can be grown on algae ponds at wastewater treatment plants.[66] This oil-rich algaecan then be extracted from the system and processed into biofuels, with the dried remainder further reprocessed tocreate ethanol. The production of algae to harvest oil for biofuels has not yet been undertaken on a commercialscale, but feasibility studies have been conducted to arrive at the above yield estimate. In addition to its projectedhigh yield, algaculture — unlike crop-based biofuels — does not entail a decrease in food production, since itrequires neither farmland nor fresh water. Many companies are pursuing algae bioreactors for various purposes,including scaling up biofuels production to commercial levels.[67][68] Prof. Rodrigo E. Teixeira from the Universityof Alabama in Huntsville demonstrated the extraction of biofuels lipids from wet algae using a simple andeconomical reaction in ionic liquids.[69]

Jatropha

Main article: Jatropha curcas

Several groups in various sectors are conducting research on Jatropha curcas, a poisonous shrub-like tree thatproduces seeds considered by many to be a viable source of biofuels feedstock oil.[70] Much of this researchfocuses on improving the overall per acre oil yield of Jatropha through advancements in genetics, soil science, andhorticultural practices.

SG Biofuels, a San Diego-based jatropha developer, has used molecular breeding and biotechnology to produceelite hybrid seeds that show significant yield improvements over first-generation varieties.[71] SG Biofuels alsoclaims additional benefits have arisen from such strains, including improved flowering synchronicity, higherresistance to pests and diseases, and increased cold-weather tolerance.[72]

Plant Research International, a department of the Wageningen University and Research Centre in the Netherlands,maintains an ongoing Jatropha Evaluation Project that examines the feasibility of large-scale jatropha cultivationthrough field and laboratory experiments.[73] The Center for Sustainable Energy Farming (CfSEF) is a LosAngeles-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 jatropha farmproduction yields by 200-300% in the next 10 years.[74]

Fungi

A group at the Russian Academy of Sciences in Moscow, in a 2008 paper, stated they had isolated large amountsof lipids from single-celled fungi and turned it into biofuels in an economically efficient manner. More research onthis fungal species, Cunninghamella japonica, and others, is likely to appear in the near future.[75] The recentdiscovery of a variant of the fungus Gliocladium roseum points toward the production of so-called myco-dieselfrom cellulose. This organism was recently discovered in the rainforests of northern Patagonia, and has the uniquecapability of converting cellulose into medium-length hydrocarbons typically found in diesel fuel.[76]

Animal Gut Bacteria

Microbial gastrointestinal flora in a variety of animals have shown potential for the production of biofuels. Recentresearch has shown that TU-103, a strain of Clostridium bacteria found in Zebra feces; can convert nearly anyform of cellulose into butanol fuel. [77] Microbes in panda waste are being investigated for their use in creatingbiofuels from bamboo and other plant materials.[78]

Greenhouse gas emissionsAccording to Britain's National Non-Food Crops Centre, total net savings from using first-generation biodiesel as atransport fuel range from 25-82% (depending on the feedstock used), compared to diesel derived from crudeoil.[79] Nobel Laureate Paul Crutzen, however, finds that the emissions of nitrous oxide due to nitrate fertilisers isseriously underestimated, and tips the balance such that most biofuels produce more greenhouse gases than thefossil fuels they replace. Producing lignocellulosic biofuels offers potentially greater greenhouse gas emissionssavings than those obtained by first-generation biofuels. Lignocellulosic biofuels are predicted by oil industry bodyCONCAWE [1] (http://www.concawe.be/) to reduce greenhouse gas emissions by around 90% when comparedwith fossil petroleum,[citation needed] in contrast first generation biofuels were found to offer savings of 20-70%[80]

Some scientists have expressed concerns about land-use change in response to greater demand for crops to use forbiofuel and the subsequent carbon emissions.[81] The payback period, that is, the time it will take biofuels to payback the carbon debt they acquire due to land-use change, has been estimated to be between 100 and 1000 years,depending on the specific instance and location of land-use change. However, no-till practices combined withcover-crop practices can reduce the payback period to three years for grassland conversion and 14 years forforest conversion.[82] Biofuels made from waste biomass or from biomass grown on abandoned agricultural landsincur little to no carbon debt.[83]

Biomass planting mandated by law (as in European Union) is causing concerns over raising food prices[84] andactual emissions reductions, as large quantities of biomass are being transported to the EU from Africa, Asia, andthe Americas (Canada, USA, Brazil).[85] For example in Poland, as much as 85% of biomass used is importedfrom outside of the EU,[86] with a single electric plant in Łódź importing over 7000 tons of wood biomass from theRepublic of Komi (Russia) over distance of 7000 kilometers on monthly basis.[87]

See alsoAviation biofuelSustainable aviation fuel

BioEthanol for Sustainable TransportBiofuels Center of North CarolinaBiofuelwatchBiogas powerplantBioheat, a biofuel blended with heating oil.Biomass briquettesCellulosic ethanolClean CitiesBiomass to liquid bio-oilDimethyl etherEnergy forestryEcological sanitationEnergy content of biofuelEnvironmental impact of aviationGreen crudeIRENALife cycle assessmentList of biofuel companies and researchersList of emerging technologiesList of vegetable oils section on oils used as biodieselLow-carbon economySustainable transportSyngasTable of biofuel crop yieldsVegetable oil economy

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Further readingCaye Drapcho, Nhuan Phú Nghiêm, Terry Walker (August 2008). Biofuels Engineering ProcessTechnology (http://www.mhprofessional.com/product.php?isbn=0071487492). [McGraw-Hill].ISBN 978-0-07-148749-8.IChemE Energy Conversion Technology Subject Group (May 2009). A Biofuels Compendium(http://www.icheme.org/biofuelscompendium). [IChemE]. ISBN 978-0-85295-533-8.Fuel Quality Directive Impact Assessment(http://www.europarl.europa.eu/registre/docs_autres_institutions/commission_europeenne/sec/2007/0055/COM_SEC(2007)0055_EN.pdf)Biofuels Journal (http://www.future-science.com/loi/bfs)James Smith (November 2010). Biofuels and the Globalisation of Risk(http://www.zedbooks.co.uk/book.asp?bookdetail=4363). [Zed Books]. ISBN 978-1-84813-572-7.Mitchell, Donald (2010). Biofuels in Africa: Opportunities, Prospects, and Challenges

(http://africaknowledgelab.worldbank.org/akl/node/67) (Available in PDF). The World Bank, Washington,D.C. ISBN 978-0-8213-8516-6. Retrieved 2011-02-08.Li, H.; Cann, A. F.; Liao, J. C. (2010). "Biofuels: Biomolecular Engineering Fundamentals and Advances".Annual Review of Chemical and Biomolecular Engineering 1: 19–36. doi:10.1146/annurev-chembioeng-073009-100938 (http://dx.doi.org/10.1146%2Fannurev-chembioeng-073009-100938). PMID 22432571(//www.ncbi.nlm.nih.gov/pubmed/22432571).

External linksEFOA (http://www.efoa.org)Alternative Fueling Station Locator (http://www.eere.energy.gov/afdc/fuels/stations_locator.html) (EERE)Towards Sustainable Production and Use of Resources: Assessing Biofuels(http://www.unep.fr/scp/rpanel/pdf/Assessing_Biofuels_Full_Report.pdf) by the United Nations EnvironmentProgramme, October 2009.Biofuels guidance for businesses, including permits and licences required(http://www.netregs.gov.uk/netregs/94953.aspx) on NetRegs.gov.ukHow Much Water Does It Take to Make Electricity? (http://www.spectrum.ieee.org/apr08/6182)—Naturalgas requires the least water to produce energy, some biofuels the most, according to a new study.International Conference on Biofuels Standards (http://ec.europa.eu/energy/res/events/biofuels.htm) -European Union Biofuels StandardizationInternational Energy Agency: Biofuels for Transport - An International Perspective(http://www.iea.org/textbase/nppdf/free/2004/biofuels2004.pdf)Biofuels from Biomass: Technology and Policy Considerations (http://web.mit.edu/professional/short-programs/courses/biofuels_biomass.html) Thorough overview from MITThe Guardian news on biofuels (http://www.guardian.co.uk/environment/biofuels)The U.S. DOE Clean Cities Program (http://www1.eere.energy.gov/cleancities/) - links to all of the CleanCities coalitions that exist throughout the U.S. (there are 87 of them)Biofuels Factsheet (http://css.snre.umich.edu/css_doc/CSS08-09.pdf) by the University of Michigan'sCenter for Sustainable Systems (http://css.snre.umich.edu/)

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