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Biofuel

From Wikipedia, in a visual modern way
A sample of biodiesel
A sample of biodiesel

Biofuel is a fuel that is produced over a short time span from biomass, rather than by the very slow natural processes involved in the formation of fossil fuels, such as oil. Biofuel can be produced from plants or from agricultural, domestic or industrial biowaste. The climate change mitigation potential of biofuel varies considerably, from emission levels comparable to fossil fuels in some scenarios to negative emissions in others. Biofuels are mostly used for transportation, but can also be used for heating and electricity.[1]: 173 [2] Biofuels (and bioenergy in general) are regarded as a renewable energy source.[3]: 11 

The two most common types of biofuel are bioethanol and biodiesel. The U.S. is the largest producer of bioethanol, while the EU is the largest producer of biodiesel. The energy content in the global production of bioethanol and biodiesel is 2.2 and 1.8 EJ per year, respectively.[4] Demand for aviation biofuel is forecast to increase.[5][6]

Bioethanol is an alcohol made by fermentation, mostly from carbohydrates produced in sugar or starch crops such as maize, 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 (E100), but it is usually used as a gasoline additive to increase octane ratings and improve vehicle emissions.

Biodiesel is produced from oils or fats using transesterification. It can be used as a fuel for vehicles in its pure form (B100), but it is usually used as a diesel additive to reduce levels of particulates, carbon monoxide, and hydrocarbons from diesel-powered vehicles.[7]

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Biomass (energy)

Biomass (energy)

Biomass (for energy) is matter from recently living (but now dead) organisms which is used for bioenergy production. Examples include wood, wood residues, energy crops, agricultural residues, and organic waste from industry and households. Wood and wood residues is the largest biomass energy source today. Wood can be used as a fuel directly or processed into pellet fuel or other forms of fuels. Other plants can also be used as fuel, for instance corn, switchgrass, miscanthus and bamboo. The main waste feedstocks are wood waste, agricultural waste, municipal solid waste, and manufacturing waste. Upgrading raw biomass to higher grade fuels can be achieved by different methods, broadly classified as thermal, chemical, or biochemical.

Fossil fuel

Fossil fuel

A fossil fuel is a hydrocarbon-containing material such as coal, oil, and natural gas, formed naturally in the Earth's crust from the remains of dead plants and animals that is extracted and burned as a fuel. Fossil fuels may be burned to provide heat for use directly, to power engines, or to generate electricity. Some fossil fuels are refined into derivatives such as kerosene, gasoline and propane before burning. The origin of fossil fuels is the anaerobic decomposition of buried dead organisms, containing organic molecules created by photosynthesis. The conversion from these materials to high-carbon fossil fuels typically require a geological process of millions of years.

Climate change mitigation

Climate change mitigation

Climate change mitigation is action to limit climate change by reducing emissions of greenhouse gases or removing those gases from the atmosphere. The recent rise in global average temperature is mostly caused by emissions from fossil fuels burning. Mitigation can reduce emissions by transitioning to sustainable energy sources, conserving energy, and increasing efficiency. In addition, CO2 can be removed from the atmosphere by enlarging forests, restoring wetlands and using other natural and technical processes, which are grouped together under the term of carbon sequestration.

Bioenergy

Bioenergy

Bioenergy is energy made from biomass, which consists of recently living organisms, mainly plants. Types of biomass commonly used for bioenergy include wood, food crops such as corn, energy crops and waste from forests, yards, or farms. The IPCC defines bioenergy as a renewable form of energy. Bioenergy can either mitigate or increase greenhouse gas emissions. There is also agreement that local environmental impacts can be problematic.

Biodiesel

Biodiesel

Biodiesel is a form of diesel fuel derived from plants or animals and consisting of long-chain fatty acid esters. It is typically made by chemically reacting lipids such as animal fat (tallow), soybean oil, or some other vegetable oil with an alcohol, producing a methyl, ethyl or propyl ester by the process of transesterification.

Aviation biofuel

Aviation biofuel

An aviation biofuel or bio-jet fuel or bio-aviation fuel (BAF) is a biofuel used to power aircraft and is said to be a sustainable aviation fuel (SAF). The International Air Transport Association (IATA) considers it a key element to reducing the carbon footprint within the environmental impact of aviation. Aviation biofuel could help decarbonize medium- and long-haul air travel generating most emissions, and could extend the life of older aircraft types by lowering their carbon footprint.

Alcohol (chemistry)

Alcohol (chemistry)

In chemistry, an alcohol is a type of organic compound that carries at least one hydroxyl functional group bound to a saturated carbon atom. Alcohols range from the simple, like methanol and ethanol, to complex, like sucrose and cholesterol. The presence of an OH group strongly modifies the properties of hydrocarbons, confering hydrophilic (water-loving) properties. The OH group provides a site at which many reactions can occur.

Ethanol fermentation

Ethanol fermentation

Ethanol fermentation, also called alcoholic fermentation, is a biological process which converts sugars such as glucose, fructose, and sucrose into cellular energy, producing ethanol and carbon dioxide as by-products. Because yeasts perform this conversion in the absence of oxygen, alcoholic fermentation is considered an anaerobic process. It also takes place in some species of fish where it provides energy when oxygen is scarce.

Carbohydrate

Carbohydrate

In organic chemistry, a carbohydrate is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 and thus with the empirical formula Cm(H2O)n, which does not mean the H has covalent bonds with O. However, not all carbohydrates conform to this precise stoichiometric definition, nor are all chemicals that do conform to this definition automatically classified as carbohydrates.

Cellulose

Cellulose

Cellulose is an organic compound with the formula (C6H10O5)n, a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell wall of green plants, many forms of algae and the oomycetes. Some species of bacteria secrete it to form biofilms. Cellulose is the most abundant organic polymer on Earth. The cellulose content of cotton fiber is 90%, that of wood is 40–50%, and that of dried hemp is approximately 57%.

Diesel fuel

Diesel fuel

Diesel fuel, also called diesel oil or historically heavy oil, is any liquid fuel specifically designed for use in a diesel engine, a type of internal combustion engine in which fuel ignition takes place without a spark as a result of compression of the inlet air and then injection of fuel. Therefore, diesel fuel needs good compression ignition characteristics.

Carbon monoxide

Carbon monoxide

Carbon monoxide is a poisonous, flammable gas that is colorless, odorless, tasteless, and slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the simplest carbon oxide. In coordination complexes the carbon monoxide ligand is called carbonyl. It is a key ingredient in many processes in industrial chemistry.

Terminology

The term "biofuel" is used in different ways. One definition is "Biofuels are biobased products, in solid, liquid, or gaseous forms. They are produced from crops or natural products, such as wood, or agricultural residues, such as molasses and bagasse."[1]: 173 

Other publications reserve the term biofuel for liquid or gaseous fuels, used for transportation.[2]

Conventional biofuels (first generation)

First-generation biofuels (also denoted as "conventional biofuels") are made from food crops grown on arable land.[8]: 447  The crop's sugar, starch, or oil content is converted into biodiesel or ethanol, using transesterification, or yeast fermentation.[9]

Advanced biofuels (second generation)

To avoid a "food versus fuel" dilemma, second-generation biofuels (also called advanced biofuels or sustainable biofuels) are made from waste products. These are derived from agriculture and forestry activities such as rice straw, rice husk, wood chips, and sawdust.[8]: 448 

The feedstock used to make the fuels either grow on arable land but are byproducts of the main crop, or they are grown on marginal land. Second-generation feedstocks also include straw, bagasse, perennial grasses, jatropha, waste vegetable oil, municipal solid waste and so forth.[10]

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Biodiesel

Biodiesel

Biodiesel is a form of diesel fuel derived from plants or animals and consisting of long-chain fatty acid esters. It is typically made by chemically reacting lipids such as animal fat (tallow), soybean oil, or some other vegetable oil with an alcohol, producing a methyl, ethyl or propyl ester by the process of transesterification.

Ethanol

Ethanol

Ethanol is an organic compound. It is an alcohol with the chemical formula C2H6O. Its formula can also be written as CH3−CH2−OH or C2H5OH. Ethanol is a volatile, flammable, colorless liquid with a characteristic wine-like odor and pungent taste. It is a psychoactive recreational drug, and the active ingredient in alcoholic drinks.

Transesterification

Transesterification

Transesterification is the process of exchanging the organic functional group R″ of an ester with the organic group R' of an alcohol. These reactions are often catalyzed by the addition of an acid or base catalyst. The reaction can also be accomplished with the help of other enzymes, particularly lipases.

Second-generation biofuels

Second-generation biofuels

Second-generation biofuels, also known as advanced biofuels, are fuels that can be manufactured from various types of non-food biomass. Biomass in this context means plant materials and animal waste used especially as a source of fuel.

Food vs. fuel

Food vs. fuel

Food versus fuel is the dilemma regarding the risk of diverting farmland or crops for biofuels production to the detriment of the food supply. The biofuel and food price debate involves wide-ranging views, and is a long-standing, controversial one in the literature. There is disagreement about the significance of the issue, what is causing it, and what can or should be done to remedy the situation. This complexity and uncertainty is due to the large number of impacts and feedback loops that can positively or negatively affect the price system. Moreover, the relative strengths of these positive and negative impacts vary in the short and long terms, and involve delayed effects. The academic side of the debate is also blurred by the use of different economic models and competing forms of statistical analysis.

Sustainable biofuel

Sustainable biofuel

Sustainable biofuel is biofuel produced in a sustainable manner. It is not based on petroleum or other fossil fuels. It includes not using plants that are used for food stuff to produce the fuel thus disrupting the worlds food supply.

Arable land

Arable land

Arable land is any land capable of being ploughed and used to grow crops. Alternatively, for the purposes of agricultural statistics, the term often has a more precise definition:Arable land is the land under temporary agricultural crops, temporary meadows for mowing or pasture, land under market and kitchen gardens and land temporarily fallow. The abandoned land resulting from shifting cultivation is not included in this category. Data for 'Arable land' are not meant to indicate the amount of land that is potentially cultivable.

Types

Biofuel energy production, 2019
Biofuel energy production, 2019

The following fuels can be produced using first, second, third or fourth-generation biofuel production procedures. Most of these can be produced using two or three of the different biofuel generation procedures.[11]

Liquid

Ethanol

Neat ethanol on the left (A), gasoline on the right (G) at a filling station in Brazil
Neat ethanol on the left (A), gasoline on the right (G) at a filling station in Brazil

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).The IEA estimates that ethanol production used 20% of sugar supplies and 13% of corn supplies in 2021. [12]

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 potato and fruit waste, 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 (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 also waste heat are more common in Europe) Waste steam fuels ethanol factory[13] – where waste heat from the factories also is used in the district heating grid. Corn-to-ethanol and other food stocks has led to the development of cellulosic ethanol.[14]

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 concerns that the economic viability is still pending.[15] The methanol economy is an alternative to the hydrogen economy to be contrasted with 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 potentially high net energy gains with biobutanol as the only liquid product. Biobutanol is often claimed to provide a direct replacement for gasoline, because it will produce more energy than ethanol and allegedly can be burned "straight" in existing gasoline engines (without modification to the engine or car),[16] and is less corrosive and less water-soluble than ethanol, and could be distributed via existing infrastructures. Escherichia coli strains have also been successfully engineered to produce butanol by modifying their amino acid metabolism.[17] One drawback to butanol production in E. coli remains the high cost of nutrient rich media, however, recent work has demonstrated E. coli can produce butanol with minimal nutritional supplementation.[18] Biobutanol is sometimes called biogasoline, which is not correct, as it is chemically different, being an alcohol, not a hydrocarbon, like biogasoline.

Biodiesel

Biofuel pumps DCA 07 2010 9834
Biofuel pumps DCA 07 2010 9834

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).[19] Feedstocks for biodiesel include animal fats, vegetable oils, soy, rapeseed, jatropha, mahua, mustard, flax, sunflower, palm oil, hemp, field pennycress, Pongamia pinnata and algae. Pure biodiesel (B100, also known as "neat" biodiesel) currently reduces emissions with up to 60% compared to diesel Second generation B100.[20] As of 2020, researchers at Australia's CSIRO have been studying safflower oil as an engine lubricant, and researchers at Montana State University's Advanced Fuels Center in the US have been studying the oil's performance in a large diesel engine, with results described as a "game-changer".[21]

Targray Biofuels Division railcar transporting Biodiesel.
Targray Biofuels Division railcar transporting Biodiesel.

Biodiesel can be used in any diesel engine and modified equipment when mixed with mineral diesel. It can also be used in its pure form (B100) in diesel engines, but some maintenance and performance problems may then occur during wintertime utilization, since the fuel becomes somewhat more viscous at lower temperatures, depending on the feedstock used.[22]

Electronically controlled 'common rail' and 'Unit Injector' type systems from the late 1990s onwards may only use biodiesel blended with conventional diesel fuel. 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 run on 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, engine filters may need to be replaced more often, as the biofuel dissolves old deposits in the fuel tank and pipes. It also effectively cleans the engine combustion 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.[23][24] Biodiesel is also an oxygenated fuel, meaning it contains a reduced amount of carbon and higher hydrogen and oxygen content than fossil diesel. This improves the combustion of biodiesel and reduces the particulate emissions from unburnt carbon. However, using pure biodiesel may increase NOx-emissions[25]

Biodiesel is also safe to handle and transport 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 °C).[26]

In France, biodiesel is incorporated at a rate of 8% in the fuel used by all French diesel vehicles.[27] Avril Group produces under the brand Diester, a fifth of 11 million tons of biodiesel consumed annually by the European Union.[28] It is the leading European producer of biodiesel.[27]

Green diesel

Green diesel is produced through hydrocracking biological oil feedstocks, such as vegetable oils and animal fats.[29][30] Hydrocracking is a refinery method that uses elevated temperatures and pressure in the presence of a catalyst to break down larger molecules, such as those found in vegetable oils, into shorter hydrocarbon chains used in diesel engines.[31] It may also be called renewable diesel, hydrotreated vegetable oil (HVO fuel)[31] or hydrogen-derived renewable diesel.[30] Unlike biodiesel, green diesel has exactly the same chemical properties as petroleum-based diesel.[31][32] 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.[30] Gasoline versions are also being developed.[33] Green diesel is being developed in Louisiana and Singapore by ConocoPhillips, Neste Oil, Valero, Dynamic Fuels, and Honeywell UOP[30][34] as well as Preem in Gothenburg, Sweden, creating what is known as Evolution Diesel.[35]

Straight vegetable oil

This truck is one of 15 based at Walmart's Buckeye, Arizona distribution center that was converted to run on a biofuel made from reclaimed cooking grease produced during food preparation at Walmart stores.[36]
This truck is one of 15 based at Walmart's Buckeye, Arizona distribution center that was converted to run on a biofuel made from reclaimed cooking grease produced during food preparation at Walmart stores.[36]

Straight unmodified edible vegetable oil is generally not used as fuel, but lower-quality oil has been used for this purpose. Used vegetable oil is increasingly being processed into biodiesel, or (more rarely) cleaned of water and particulates and then used as a fuel. The IEA estimates that biodiesel production used 17% of global vegetable oil supplies in 2021.[12]

Oils and fats reacted with 10 pounds of a short-chain alcohol (usually methanol) in the presence of a catalyst (usually sodium hydroxide [NaOH] can be hydrogenated to give a diesel substitute.[37] 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, no storage stability problems and no susceptibility to microbial attack.[38]

Biogasoline

A study led by Professor Lee Sang-yup at the Korea Advanced Institute of Science and Technology (KAIST) and published in the international science journal Nature used modified E. coli fed with glucose found in plants or other non-food crops to produce biogasoline with the produced enzymes. The enzymes converted the sugar into fatty acids and then turned these into hydrocarbons that were chemically and structurally identical to those found in commercial gasoline fuel.[39]

Bioethers

Biofuel production by region
Biofuel production by region

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."[40] Bioethers are created from wheat or sugar beets, and also be produced from the waste glycerol that results from the production of biodiesel.[41] They also enhance engine performance, while significantly reducing engine wear and toxic exhaust emissions. Although bioethers are likely to replace ethers produced from petrolium in the UK, it is highly unlikely they will become a fuel in and of itself due to the low energy density.[42] By greatly reducing the amount of ground-level ozone emissions, they contribute to air quality.[43][44]

When it comes to transportation fuel there are six ether additives: dimethyl ether (DME), diethyl ether (DEE), methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), tert-amyl methyl ether (TAME), and tert-amyl ethyl ether (TAEE).[45]

The European Fuel Oxygenates Association identifies MTBE and 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.[46] Although Europeans still use bioether additives, the U.S. Energy Policy Act of 2005 lifted a requirement for reformulated gasoline to include an oxygenate, leading to less MTBE being added to fuel.[47]

Aviation biofuel

Refueling an Airbus A320 with biofuel
Refueling an Airbus A320 with biofuel

An aviation biofuel or bio-jet fuel[48] or bio-aviation fuel (BAF)[49] is a biofuel used to power aircraft and is said to be a sustainable aviation fuel (SAF). The International Air Transport Association (IATA) considers it a key element to reducing the carbon footprint within the environmental impact of aviation.[50] Aviation biofuel could help decarbonize medium- and long-haul air travel generating most emissions, and could extend the life of older aircraft types by lowering their carbon footprint.

Biofuels are biomass-derived fuels from plants or waste; depending on which type of biomass is used, they could lower CO2 emissions by 20–98% compared to conventional jet fuel.[51] The first test flight using blended biofuel was in 2008, and in 2011 blended fuels with 50% biofuels were allowed in commercial flights. In 2019, the IATA was aiming for a 2% penetration by 2025.

Aviation biofuel can be produced from plant sources such as Jatropha, algae, tallows, waste oils, palm oil, Babassu, and Camelina (bio-SPK); from solid biomass using pyrolysis processed with a Fischer–Tropsch process (FT-SPK); with an alcohol-to-jet (ATJ) process from waste fermentation; or from synthetic biology through a solar reactor. Small piston engines can be modified to burn ethanol.

Sustainable biofuels do not compete with food crops, prime agricultural land, natural forest or fresh water. They are an alternative to electrofuels.[52] Sustainable aviation fuel is certified as being sustainable by a third-party organisation.

Gaseous

Biogas and biomethane

Biogas
Biogas

Biogas is methane produced by the process of anaerobic digestion of organic material by anaerobes.[53] 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 be used as a biofuel or a fertilizer. When CO2 and other impurities are removed from biogas, it is called biomethane.

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

Farmers can produce biogas from manure from their cattle by using anaerobic digesters.[54]

Syngas

Syngas, a mixture of carbon monoxide, hydrogen and various 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.[38] 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 may be burned directly in internal combustion engines, turbines or high-temperature fuel cells.[55] The wood gas generator, a wood-fueled gasification reactor, can be connected to an internal combustion engine.

Syngas can be used to produce methanol, dimethyl ether and hydrogen, or converted via the Fischer–Tropsch process to produce a diesel substitute, or a mixture of alcohols that can be blended into gasoline. Gasification normally relies on temperatures greater than 700 °C.

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

Solid

The term "biofuels" is also used for solid fuels that are made from biomass, even though this is less common.[2]

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Ethanol fuel

Ethanol fuel

Ethanol fuel is fuel containing ethyl alcohol, the same type of alcohol as found in alcoholic beverages. It is most often used as a motor fuel, mainly as a biofuel additive for gasoline.

Gasoline

Gasoline

Gasoline or petrol is a transparent, petroleum-derived flammable liquid that is used primarily as a fuel in most spark-ignited internal combustion engines. It consists mostly of organic compounds obtained by the fractional distillation of petroleum, enhanced with a variety of additives. On average, U.S. refineries produce, from a barrel of crude oil, about 19 to 20 gallons of gasoline; 11 to 13 gallons of distillate fuel ; and 3 to 4 gallons of jet fuel. The product ratio depends on the processing in an oil refinery and the crude oil assay. A barrel of oil is defined as holding 42 US gallons, which is about 159 liters or 35 imperial gallons.

Filling station

Filling station

A filling station, also known as a gas station or petrol station, is a facility that sells fuel and engine lubricants for motor vehicles. The most common fuels sold in the 2010s were gasoline and diesel fuel.

Butanol fuel

Butanol fuel

Butanol may be used as a fuel in an internal combustion engine. It is more similar to gasoline than it is to ethanol. A C4-hydrocarbon, butanol is a drop-in fuel and thus works in vehicles designed for use with gasoline without modification. Both n-butanol and isobutanol have been studied as possible fuels. Both can be produced from biomass (as "biobutanol" ) as well as from fossil fuels (as "petrobutanol"). The chemical properties depend on the isomer (n-butanol or isobutanol), not on the production method.

Microorganism

Microorganism

A microorganism, or microbe, is an organism of microscopic size, which may exist in its single-celled form or as a colony of cells.

Enzyme

Enzyme

Enzymes are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. Almost all metabolic processes in the cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps. The study of enzymes is called enzymology and the field of pseudoenzyme analysis recognizes that during evolution, some enzymes have lost the ability to carry out biological catalysis, which is often reflected in their amino acid sequences and unusual 'pseudocatalytic' properties.

Ethanol fuel in Brazil

Ethanol fuel in Brazil

Brazil is the world's second largest producer of ethanol fuel. Brazil and the United States have led the industrial production of ethanol fuel for several years, together accounting for 85 percent of the world's production in 2017. Brazil produced 26.72 billion liters, representing 26.1 percent of the world's total ethanol used as fuel in 2017.

Alcohol fuel

Alcohol fuel

Various alcohols are used as fuel for internal combustion engines. The first four aliphatic alcohols are of interest as fuels because they can be synthesized chemically or biologically, and they have characteristics which allow them to be used in internal combustion engines. The general chemical formula for alcohol fuel is CnH2n+1OH.

Maize

Maize

Maize, also known as corn in North American and Australian English, is a cereal grain first domesticated by indigenous peoples in southern Mexico about 10,000 years ago. The leafy stalk of the plant produces pollen inflorescences and separate ovuliferous inflorescences called ears that when fertilized yield kernels or seeds, which are fruits. The term maize is preferred in formal, scientific, and international usage as the common name because this refers specifically to this one grain whereas corn refers to any principal cereal crop cultivated in a country. For example, in North America and Australia corn is often used for maize, but in England and Wales it can refer to wheat or barley, and in Scotland and Ireland to oats.

Molasses

Molasses

Molasses is a viscous substance resulting from refining sugarcane or sugar beets into sugar. Molasses varies in the amount of sugar, method of extraction and age of the plant. Sugarcane molasses is primarily used to sweeten and flavour foods. Molasses is a major constituent of fine commercial brown sugar. It is also one of the primary ingredients used to distill rum.

Alcoholic beverage

Alcoholic beverage

An alcoholic beverage is a drink that contains ethanol, a type of alcohol that acts as a drug and is produced by fermentation of grains, fruits, or other sources of sugar. The consumption of alcoholic drinks, often referred to as "drinking", plays an important social role in many cultures. Most countries have laws regulating the production, sale, and consumption of alcoholic beverages. Regulations may require the labeling of the percentage alcohol content and the use of a warning label. Some countries ban such activities entirely, but alcoholic drinks are legal in most parts of the world. The global alcoholic drink industry exceeded $1 trillion in 2018.

Fruit

Fruit

In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering.

Research into other types

Algae-based biofuels

Algae can be produced in ponds or tanks on land, and out at sea.[56][57] Algal fuels have high yields,[58] can be grown with minimal impact on fresh water resources,[59][60][61] can be produced using saline water and wastewater, have a high ignition point,[62] and are biodegradable and relatively harmless to the environment if spilled.[63][64] Production requires large amounts of energy and fertilizer, the produced fuel degrades faster than other biofuels, and it does not flow well in cold temperatures.[56]

By 2017, due to economic considerations, most efforts to produce fuel from algae have been abandoned or changed to other applications.[65]

Electrofuels and solar fuels

This class of biofuels includes electrofuels and solar fuels. Electrofuels are made by storing electrical energy in the chemical bonds of liquids and gases. The primary targets are butanol, biodiesel, and hydrogen, but include other alcohols and carbon-containing gases such as methane and butane. A solar fuel is a synthetic chemical fuel produced from solar energy. Light is converted to chemical energy, typically by reducing protons to hydrogen, or carbon dioxide to organic compounds.[66]

Fourth-generation biofuels also include biofuels that are produced by bioengineered organisms i.e. algae and cyanobacteria.[67] Algae and cyanobacteria will use water, carbon dioxide, and solar energy to produce biofuels.[67] This method of biofuel production is still at the research level. The biofuels that are secreted by the bioengineered organisms are expected to have higher photon-to-fuel conversion efficiency, compared to older generations of biofuels.[67] One of the advantages of this class of biofuels is that the cultivation of the organisms that produce the biofuels does not require the use of arable land.[68] The disadvantages include the cost of cultivating the biofuel-producing organisms being very high.[68]

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Algaculture

Algaculture

Algaculture is a form of aquaculture involving the farming of species of algae.

Algae fuel

Algae fuel

Algae fuel, algal biofuel, or algal oil is an alternative to liquid fossil fuels that uses algae as its source of energy-rich oils. Also, algae fuels are an alternative to commonly known biofuel sources, such as corn and sugarcane. When made from seaweed (macroalgae) it can be known as seaweed fuel or seaweed oil.

Fresh water

Fresh water

Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include non-salty mineral-rich waters such as chalybeate springs. Fresh water may encompass frozen and meltwater in ice sheets, ice caps, glaciers, snowfields and icebergs, natural precipitations such as rainfall, snowfall, hail/sleet and graupel, and surface runoffs that form inland bodies of water such as wetlands, ponds, lakes, rivers, streams, as well as groundwater contained in aquifers, subterranean rivers and lakes. Fresh water is the water resource that is of the most and immediate use to humans.

Flash point

Flash point

The flash point of a material is the "lowest liquid temperature at which, under certain standardized conditions, a liquid gives off vapours in a quantity such as to be capable of forming an ignitable vapour/air mixture".

Electrofuel

Electrofuel

Electrofuels, also known as e-fuels, a class of synthetic fuels, are a type of drop-in replacement fuel. They are manufactured using captured carbon dioxide or carbon monoxide, together with hydrogen obtained from sustainable electricity sources such as wind, solar and nuclear power.

Electrical energy

Electrical energy

Electrical energy is energy related to forces on electrically-charged particles and the movement of those particles. This energy is supplied by the combination of current and electric potential that is delivered by a circuit. Motion (current) is not required; for example, if there is a voltage difference in combination with charged particles, such as static electricity or a charged capacitor, the moving electrical energy is typically converted to another form of energy.

Butanol

Butanol

Butanol (also called butyl alcohol) is a four-carbon alcohol with a formula of C4H9OH, which occurs in five isomeric structures (four structural isomers), from a straight-chain primary alcohol to a branched-chain tertiary alcohol; all are a butyl or isobutyl group linked to a hydroxyl group (sometimes represented as BuOH, n-BuOH, i-BuOH, and t-BuOH). These are n-butanol, 2 stereoisomers of sec-butanol, isobutanol and tert-butanol. Butanol is primarily used as a solvent and as an intermediate in chemical synthesis, and may be used as a fuel. Biologically produced butanol is called biobutanol, which may be n-butanol or isobutanol.

Butane

Butane

Butane or n-butane is an alkane with the formula C4H10. Butane is a highly flammable, colorless, easily liquefied gas that quickly vaporizes at room temperature and pressure. The name butane comes from the root but- (from butyric acid, named after the Greek word for butter) and the suffix -ane. It was discovered in crude petroleum in 1864 by Edmund Ronalds, who was the first to describe its properties, and commercialized by Walter O. Snelling in early 1910s.

Fuel

Fuel

A fuel is any material that can be made to react with other substances so that it releases energy as thermal energy or to be used for work. The concept was originally applied solely to those materials capable of releasing chemical energy but has since also been applied to other sources of heat energy, such as nuclear energy.

Chemical energy

Chemical energy

Chemical energy is the energy of chemical substances that is released when they undergo a chemical reaction and transform into other substances. Some examples of storage media of chemical energy include batteries, food, and gasoline. Breaking and re-making chemical bonds involves energy, which may be either absorbed by or evolved from a chemical system. If reactants with relatively weak electron-pair bonds convert to more strongly bonded products, energy is released. Therefore, relatively weakly bonded and unstable molecules store chemical energy.

Hydrogen

Hydrogen

Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula H2. It is colorless, odorless, tasteless, non-toxic, and highly combustible. Hydrogen is the most abundant chemical substance in the universe, constituting roughly 75% of all normal matter. Stars such as the Sun are mainly composed of hydrogen in the plasma state. Most of the hydrogen on Earth exists in molecular forms such as water and organic compounds. For the most common isotope of hydrogen each atom has one proton, one electron, and no neutrons.

Carbon dioxide

Carbon dioxide

Carbon dioxide is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature, and as the source of available carbon in the carbon cycle, atmospheric CO2 is the primary carbon source for life on Earth. In the air, carbon dioxide is transparent to visible light but absorbs infrared radiation, acting as a greenhouse gas. Carbon dioxide is soluble in water and is found in groundwater, lakes, ice caps, and seawater. When carbon dioxide dissolves in water, it forms carbonate and mainly bicarbonate, which causes ocean acidification as atmospheric CO2 levels increase.

Extent of production and use

Global biofuel production was 81 Mtoe in 2017 which represented an annual increase of about 3% compared to 2010.[3]: 12  Mtoe stands for Million Tonnes of Oil Equivalent. Furthermore: "the US is the largest producer in the world producing 37 Mtoe in 2017; Brazil and South America, 23 Mtoe; and Europe (mainly Germany) 12 Mtoe".[3]: 12 

An assessment from 2017 found that: "Biofuels will never be a major transport fuel as there is just not enough land in the world to grow plants to make biofuel for all vehicles. It can however, be part of an energy mix to take us into a future of renewable energy."[3]: 11 

In 2021, worldwide biofuel production provided 4.3% of the world's fuels for transport, including a very small amount of aviation biofuel.[69] By 2027 worldwide biofuel production is expected to supply 5.4% of the world’s fuels for transport including 1% of aviation fuel.[69] The International Energy Agency (IEA) wants biofuels to make up 64% of the world demand for transportation fuels by 2050, in order to reduce dependency on petroleum.[12] However, the production and consumption of biofuels are not on track to meet the IEA's sustainable development scenario.[70][71] From 2020 to 2030 global biofuel output has to increase by 16% each year to reach IEA's goal.[70]

Discover more about Extent of production and use related topics

Tonne of oil equivalent

Tonne of oil equivalent

The tonne of oil equivalent (toe) is a unit of energy defined as the amount of energy released by burning one tonne of crude oil. It is approximately 42 gigajoules or 11.630 megawatt-hours, although as different crude oils have different calorific values, the exact value is defined by convention; several slightly different definitions exist. The toe is sometimes used for large amounts of energy.

Renewable energy

Renewable energy

Renewable energy is energy from renewable resources that are naturally replenished on a human timescale. Renewable resources include sunlight, wind, the movement of water, and geothermal heat. Although most renewable energy sources are sustainable, some are not. For example, some biomass sources are considered unsustainable at current rates of exploitation. Renewable energy is often used for electricity generation, heating and cooling. Renewable energy projects are typically large-scale, but they are also suited to rural and remote areas and developing countries, where energy is often crucial in human development. Renewable energy is often deployed together with further electrification, which has several benefits: electricity can move heat or objects efficiently, and is clean at the point of consumption. In addition, electrification with renewable energy is more efficient and therefore leads to significant reductions in primary energy requirements.

Aviation biofuel

Aviation biofuel

An aviation biofuel or bio-jet fuel or bio-aviation fuel (BAF) is a biofuel used to power aircraft and is said to be a sustainable aviation fuel (SAF). The International Air Transport Association (IATA) considers it a key element to reducing the carbon footprint within the environmental impact of aviation. Aviation biofuel could help decarbonize medium- and long-haul air travel generating most emissions, and could extend the life of older aircraft types by lowering their carbon footprint.

International Energy Agency

International Energy Agency

The International Energy Agency (IEA) is a Paris-based autonomous intergovernmental organisation, established in 1974, that provides policy recommendations, analysis and data on the entire global energy sector. The 31 member countries and 11 association countries of the IEA represent 75% of global energy demand.

Issues

Wheat fields in the USA: wheat is grown for food but also for biofuel production.
Wheat fields in the USA: wheat is grown for food but also for biofuel production.
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 moderating oil prices, the "food vs fuel" debate, poverty reduction potential, carbon emissions levels, sustainable biofuel production, deforestation and soil erosion, loss of biodiversity, effect on water resources, the possible modifications necessary to run the engine on biofuel, as well as energy balance and efficiency. The International Resource Panel, which provides independent scientific assessments and expert advice on a variety of resource-related themes, assessed the issues relating to biofuel use in its first report Towards sustainable production and use of resources: Assessing Biofuels.[72] In it, it outlined the wider and interrelated factors that need to be considered when deciding on the relative merits of pursuing one biofuel over another. It concluded that not all biofuels perform equally in terms of their effect on climate, energy security and ecosystems, and suggested that environmental and social effects need to be assessed throughout the entire life-cycle.

Environmental impacts

Estimates about the climate impact from biofuels vary widely based on the methodology and exact situation examined.[73]

In general, biofuels emit fewer greenhouse gas emissions when burned in an engine and are generally considered carbon-neutral fuels as the carbon emitted has been captured from the atmosphere by the crops used in production.[74] However, life-cycle assessments of biofuels have shown large emissions associated with the potential land-use change required to produce additional biofuel feedstocks.[73][75] A review of 179 studies published between 2009 and 2020 found that if no land-use change is involved, first-generation biofuels can—on average—have lower emissions than fossil fuels.[73] However, there is an issue with competition with food. Up to 40% of corn produced in the United States is used to make ethanol,[76] and worldwide 10% of all grain is turned into biofuel.[77] A 50% reduction in grain used for biofuels in the US and Europe would replace all of Ukraine's grain exports.[78] Also, several studies have shown that reductions in emissions from biofuels are achieved at the expense of other impacts, such as acidification, eutrophication, water footprint and biodiversity loss.[73]

The use of second generation biofuels is thought to increase environmental sustainability, since the non-food part of plants is being used to produce second-generation biofuels, instead of being disposed.[79] But the use of this class of biofuels increases the competition for lignocellulosic biomass, increasing the cost of these biofuels.[80]

Indirect land use change impacts of biofuels

The indirect land use change impacts of biofuels, also known as ILUC or iLUC (pronounced as i-luck), relates to the unintended consequence of releasing more carbon emissions due to land-use changes around the world induced by the expansion of croplands for ethanol or biodiesel production in response to the increased global demand for biofuels.[81][82]

As farmers worldwide respond to higher crop prices in order to maintain the global food supply-and-demand balance, pristine lands are cleared to replace the food crops that were diverted elsewhere to biofuels' production. Because natural lands, such as rainforests and grasslands, store carbon in their soil and biomass as plants grow each year, clearance of wilderness for new farms translates to a net increase in greenhouse gas emissions. Due to this off-site change in the carbon stock of the soil and the biomass, indirect land use change has consequences in the greenhouse gas (GHG) balance of a biofuel.[81][82][83][84]

Other authors have also argued that indirect land use changes produce other significant social and environmental impacts, affecting biodiversity, water quality, food prices and supply, land tenure, worker migration, and community and cultural stability.[83][85][86][87]

Discover more about Issues related topics

Issues relating to biofuels

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 moderating oil prices, the "food vs fuel" debate, poverty reduction potential, carbon emissions levels, sustainable biofuel production, deforestation and soil erosion, loss of biodiversity, effect on water resources, the possible modifications necessary to run the engine on biofuel, as well as energy balance and efficiency. The International Resource Panel, which provides independent scientific assessments and expert advice on a variety of resource-related themes, assessed the issues relating to biofuel use in its first report Towards sustainable production and use of resources: Assessing Biofuels. In it, it outlined the wider and interrelated factors that need to be considered when deciding on the relative merits of pursuing one biofuel over another. It concluded that not all biofuels perform equally in terms of their effect on climate, energy security and ecosystems, and suggested that environmental and social effects need to be assessed throughout the entire life-cycle.

Poverty reduction

Poverty reduction

Poverty reduction, poverty relief, or poverty alleviation, is a set of measures, both economic and humanitarian, that are intended to permanently lift people out of poverty.

Sustainable biofuel

Sustainable biofuel

Sustainable biofuel is biofuel produced in a sustainable manner. It is not based on petroleum or other fossil fuels. It includes not using plants that are used for food stuff to produce the fuel thus disrupting the worlds food supply.

Deforestation

Deforestation

Deforestation or forest clearance is the removal of a forest or stand of trees from land that is then converted to non-forest use. Deforestation can involve conversion of forest land to farms, ranches, or urban use. The most concentrated deforestation occurs in tropical rainforests. About 31% of Earth's land surface is covered by forests at present. This is one-third less than the forest cover before the expansion of agriculture, a half of that loss occurring in the last century. Between 15 million to 18 million hectares of forest, an area the size of Bangladesh, are destroyed every year. On average 2,400 trees are cut down each minute.

Soil erosion

Soil erosion

Soil erosion is the denudation or wearing away of the upper layer of soil. It is a form of soil degradation. This natural process is caused by the dynamic activity of erosive agents, that is, water, ice (glaciers), snow, air (wind), plants, and animals. In accordance with these agents, erosion is sometimes divided into water erosion, glacial erosion, snow erosion, wind (aeolean) erosion, zoogenic erosion and anthropogenic erosion such as tillage erosion. Soil erosion may be a slow process that continues relatively unnoticed, or it may occur at an alarming rate causing a serious loss of topsoil. The loss of soil from farmland may be reflected in reduced crop production potential, lower surface water quality and damaged drainage networks. Soil erosion could also cause sinkholes.

Biodiversity loss

Biodiversity loss

Biodiversity loss includes the worldwide extinction of different species, as well as the local reduction or loss of species in a certain habitat, resulting in a loss of biological diversity. The latter phenomenon can be temporary or permanent, depending on whether the environmental degradation that leads to the loss is reversible through ecological restoration/ecological resilience or effectively permanent. The current global extinction, has resulted in a biodiversity crisis being driven by human activities which push beyond the planetary boundaries and so far has proven irreversible.

International Resource Panel

International Resource Panel

The International Resource Panel is a scientific panel of experts that aims to help nations use natural resources sustainably without compromising economic growth and human needs. It provides independent scientific assessments and expert advice on a variety of areas, including:the volume of selected raw material reserves and how efficiently these resources are being used the lifecycle-long environmental impacts of products and services created and consumed around the globe options to meet human and economic needs with fewer or cleaner resources.

Energy security

Energy security

Energy security is the association between national security and the availability of natural resources for energy consumption. Access to cheaper energy has become essential to the functioning of modern economies. However, the uneven distribution of energy supplies among countries has led to significant vulnerabilities. International energy relations have contributed to the globalization of the world leading to energy security and energy vulnerability at the same time.

Greenhouse gas emissions

Greenhouse gas emissions

Greenhouse gas emissions from human activities strengthen the greenhouse effect, contributing to climate change. Most is carbon dioxide from burning fossil fuels: coal, oil, and natural gas. The largest emitters include coal in China and large oil and gas companies. Human-caused emissions have increased atmospheric carbon dioxide by about 50% over pre-industrial levels. The growing levels of emissions have varied, but have been consistent among all greenhouse gases (GHGs). Emissions in the 2010s averaged 56 billion tons a year, higher than any decade before.

Carbon-neutral fuel

Carbon-neutral fuel

Carbon-neutral fuel is fuel which produces no net-greenhouse gas emissions or carbon footprint. In practice, this usually means fuels that are made using carbon dioxide (CO2) as a feedstock. Proposed carbon-neutral fuels can broadly be grouped into synthetic fuels, which are made by chemically hydrogenating carbon dioxide, and biofuels, which are produced using natural CO2-consuming processes like photosynthesis.

Life-cycle assessment

Life-cycle assessment

Life cycle assessment or LCA is a methodology for assessing environmental impacts associated with all the stages of the life cycle of a commercial product, process, or service. For instance, in the case of a manufactured product, environmental impacts are assessed from raw material extraction and processing (cradle), through the product's manufacture, distribution and use, to the recycling or final disposal of the materials composing it (grave).

Ocean acidification

Ocean acidification

Ocean acidification is the decrease in the pH of the Earth’s ocean. Between 1950 and 2020, the average pH of the ocean surface fell from approximately 8.15 to 8.05. Carbon dioxide emissions from human activities are the primary cause of ocean acidification, with atmospheric carbon dioxide (CO2) levels exceeding 410 ppm (in 2020). CO2 from the atmosphere is absorbed by the oceans. This produces carbonic acid (H2CO3) which dissociates into a bicarbonate ion (HCO−3) and a hydrogen ion (H+). The presence of free hydrogen ions (H+) lowers the pH of the ocean, increasing acidity (this does not mean that seawater is acidic yet; it is still alkaline, with a pH higher than 8). Marine calcifying organisms, such as mollusks and corals, are especially vulnerable because they rely on calcium carbonate to build shells and skeletons.

Source: "Biofuel", Wikipedia, Wikimedia Foundation, (2023, March 25th), https://en.wikipedia.org/wiki/Biofuel.

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See also
References
  1. ^ a b "Chapter 9: Biofuels for transport". Future energy : improved, sustainable and clean options for our planet. T. M. Letcher (3rd ed.). Amsterdam, Netherlands. 2020. ISBN 978-0-08-102887-2. OCLC 1137604985.{{cite book}}: CS1 maint: others (link)
  2. ^ a b c "Biofuels explained - U.S. Energy Information Administration (EIA)". www.eia.gov. Retrieved 24 January 2023.
  3. ^ a b c d "Chapter1: Introduction With a Focus on Atmospheric Carbon Dioxide and Climate Change". Future energy : improved, sustainable and clean options for our planet. T. M. Letcher (3rd ed.). Amsterdam, Netherlands. 2020. ISBN 978-0-08-102887-2. OCLC 1137604985.{{cite book}}: CS1 maint: others (link)
  4. ^ "Renewables Report 2022". IEA.
  5. ^ "Biofuel is approaching a feedstock crunch. How bad? And what must be done?". Energy Post. 23 January 2023. Retrieved 30 January 2023.
  6. ^ "How to scale Sustainable Aviation Fuel in the next decade". World Economic Forum. Retrieved 30 January 2023.
  7. ^ Bayetero CM, Yépez CM, Cevallos IB, Rueda EH (January 2022). "Effect of the use of additives in biodiesel blends on the performance and opacity of a diesel engine". Materials Today: Proceedings. Advances in Mechanical Engineering Trends. 49: 93–99. doi:10.1016/j.matpr.2021.07.478. ISSN 2214-7853. S2CID 238787289.
  8. ^ a b "Chapter 21: Energy from biomass". Future energy : improved, sustainable and clean options for our planet. T. M. Letcher (3rd ed.). Amsterdam, Netherlands. 2020. ISBN 978-0-08-102887-2. OCLC 1137604985.{{cite book}}: CS1 maint: others (link)
  9. ^ "What are – and who's making – 2G, 3G and 4G biofuels? : Biofuels Digest - biofuels, biodiesel, ethanol, algae, jatropha, green gasoline, green diesel, and biocrude daily news". 21 May 2010. Archived from the original on 21 May 2010.
  10. ^ "Biofuels – Second Generation Biofuels". biofuel.org.uk. Archived from the original on 15 July 2019. Retrieved 18 January 2018.
  11. ^ Ethanol for instance can be produced using 1G, 2G and 3G procedures
  12. ^ a b c "Is the biofuel industry approaching a feedstock crunch? – Analysis". IEA. Retrieved 2 January 2023.
  13. ^ "Energikunskap | Lär dig mer om energi – E.ON". Archived from the original on 27 October 2014. Retrieved 21 June 2014.
  14. ^ Houghton J, Weatherwax S, Ferrell J (7 June 2006). Breaking the biological barriers to cellulosic ethanol: a joint research agenda (Report). Washington, DC (United States): EERE Publication and Product Library. doi:10.2172/1218382.
  15. ^ Börjesson P, Lundgren J, Ahlgren S, Nyström I (18 June 2013). Dagens och framtidens hållbara biodrivmedel: underlagsrapport från f3 till utredningen om fossilfri fordonstrafik [Today's and the future's sustainable biofuels: background report from f3 to the inquiry into fossil-free vehicle traffic.] (Report) (in Swedish). Vol. 13. The Swedish Knowledge Centre for Renewable Transportation Fuels. p. 170.
  16. ^ "ButylFuel, LLC Main Page". Butanol.com. 15 August 2005. Archived from the original on 10 July 2019. Retrieved 14 July 2010.
  17. ^ Evans J (14 January 2008). "Biofuels aim higher". Biofuels, Bioproducts and Biorefining (BioFPR). Archived from the original on 10 August 2009. Retrieved 3 December 2008.
  18. ^ Pontrelli S, Fricke RC, Sakurai SS, Putri SP, Fitz-Gibbon S, Chung M, et al. (September 2018). "Directed strain evolution restructures metabolism for 1-butanol production in minimal media". Metabolic Engineering. 49: 153–163. doi:10.1016/j.ymben.2018.08.004. PMID 30107263.
  19. ^ Fukuda H, Kondo A, Noda H (January 2001). "Biodiesel fuel production by transesterification of oils". Journal of Bioscience and Bioengineering. 92 (5): 405–416. doi:10.1016/s1389-1723(01)80288-7. PMID 16233120.
  20. ^ "Perstop Press release: Verdis Polaris Aura – second generation B100 – The advanced green one". Archived from the original on 4 August 2014. Retrieved 21 June 2014.
  21. ^ Lee T (7 June 2020). "Safflower oil hailed by scientists as possible recyclable, biodegradable replacement for petroleum". ABC News. Landline. Australian Broadcasting Corporation. Archived from the original on 7 June 2020. Retrieved 7 June 2020.
  22. ^ "Alternative Fuels Data Center: Biodiesel Blends". afdc.energy.gov. Retrieved 31 March 2022.
  23. ^ "ADM Biodiesel: Hamburg, Leer, Mainz". Biodiesel.de. Archived from the original on 2 August 2009. Retrieved 14 July 2010.
  24. ^ RRI Limited for Biodiesel Filling Stations. "Welcome to Biodiesel Filling Stations". Biodieselfillingstations.co.uk. Archived from the original on 14 July 2018. Retrieved 14 July 2010.
  25. ^ Nylund NO, Koponen K (2012). Fuel and Technology Alternatives for Buses. Overall Energy Efficiency and Emission Performance. IEA Bioenergy Task 46 (PDF) (Report). VTT Technical Research Centre of Finland. Archived from the original (PDF) on 16 February 2020.. Possibly the new emission standards Euro VI/EPA 10 will lead to reduced NOx-levels also when using B100.
  26. ^ "Biofuels Facts". Hempcar.org. Archived from the original on 20 May 2011. Retrieved 14 July 2010.
  27. ^ a b Avril Group : Activity Report 2014, p. 58
  28. ^ EurObserv 2014, p. 4
  29. ^ Brown R, Holmgren J. "Fast Pyrolysis and Bio-Oil Upgrading" (PDF). Archived (PDF) from the original on 5 January 2012. Retrieved 15 March 2012.
  30. ^ a b c d "Alternative & Advanced Fuels". US Department of Energy. Archived from the original on 27 October 2012. Retrieved 7 March 2012.
  31. ^ a b c Knothe G (June 2010). "Biodiesel and renewable diesel: a comparison". Progress in Energy and Combustion Science. 36 (3): 364–373. doi:10.1016/j.pecs.2009.11.004. Archived from the original on 6 November 2012. Retrieved 23 August 2012.
  32. ^ "Green Diesel v. Biodiesel". Archived from the original on 5 August 2018. Retrieved 5 August 2018.
  33. ^ Jessica E. "Breakthroughs in Green Gasoline Production". Biomass Magazine. Archived from the original on 11 March 2012. Retrieved 14 August 2012.
  34. ^ Albrecht KO, Hallen RT (March 2011). A Brief Literature Overview of Various Routes to Biorenewable Fuels from Lipids for the National Alliance of Advanced Biofuels and Bio-products NAAB Consortium (PDF) (Report). Prepared by the US Department of Energy. Archived (PDF) from the original on 12 July 2012. Retrieved 23 August 2012.
  35. ^ "Preem makes major investment in green diesel at the Port of Gothenburg – Port of Gothenburg". August 2014. Archived from the original on 1 August 2014.
  36. ^ "Wal-Mart To Test Hybrid Trucks". Sustainable Business. 3 February 2009. Archived from the original on 8 May 2014. Retrieved 8 May 2014.
  37. ^ "Alternative Fuels Data Center: Biodiesel Production and Distribution". afdc.energy.gov. Retrieved 31 March 2022.
  38. ^ a b Evans G (14 April 2008). Liquid Transport Biofuels – Technology Status Report (Report). National Non-Food Crops Centre. Archived from the original on 11 June 2008.
  39. ^ Liquid Transport Fuels&Lubes - South Korean scientists use E. coli to make gasoline (Report). Fuels&Lubes Daily. 4 November 2013. Archived from the original on 7 September 2022.
  40. ^ Rock K, Korpelshoek M (2007). "Bioethers Impact on the Gasoline Pool". Digital Refining. Archived from the original on 14 November 2016. Retrieved 15 February 2014.
  41. ^ "Biofuels - Types of Biofuels - Bioethers". biofuel.org.uk. Archived from the original on 1 February 2016.
  42. ^ "Biofuels – Types of Biofuels – Bioethers". Archived from the original on 1 February 2016. Retrieved 30 May 2015.
  43. ^ "Council Directive 85/536/EEC of 5 December 1985 on crude-oil savings through the use of substitute fuel components in petrol". Eur-lex.europa.eu. Archived from the original on 21 May 2011. Retrieved 14 July 2010.
  44. ^ "Impact Assessment of the Proposal for a Directive of the European Parliament and of the Council modifying Directive 98/70/EC relating to the quality of petrol and diesel fuels" (PDF). Brussels: Commission of the European Communities. 31 January 2007. Archived (PDF) from the original on 15 July 2011. Retrieved 14 July 2010.
  45. ^ Sukla MK, Bhaskar T, Jain AK, Singal SK, Garg MO. "Bio-Ethers as Transportation Fuel: A Review" (PDF). Indian Institute of Petroleum Dehradun. Archived (PDF) from the original on 14 October 2011. Retrieved 15 February 2014.
  46. ^ "What are Bio-Ethers?" (PDF). . The European Fuel Oxygenates Association. Archived from the original (PDF) on 6 March 2014.
  47. ^ "Gasoline". Environmental Protection Agency. Archived from the original on 6 December 2013. Retrieved 6 March 2014.
  48. ^ "Sustainable aviation fuel market demand drives new product launches". Investable Universe. 4 December 2020. Retrieved 12 December 2022. Note: Investable Universe>About
  49. ^ Doliente, Stephen S.; et al. (10 July 2020). "Bio-aviation Fuel: A Comprehensive Review and Analysis of the Supply Chain Components". Frontiers in Energy Research. 8. doi:10.3389/fenrg.2020.00110.
  50. ^ "Developing Sustainable Aviation Fuel (SAF)". IATA.
  51. ^ Bauen, Ausilio; Howes, Jo; Bertuccioli, Luca; Chudziak, Claire (August 2009). "Review of the potential for biofuels in aviation". CiteSeerX 10.1.1.170.8750.
  52. ^ Mark Pilling (25 March 2021). "How sustainable fuel will help power aviation's green revolution". Flight Global.
  53. ^ "National Non-Food Crops Centre - NNFCC 08-006 A Detailed Economic Assessment of Anaerobic Digestion Technology and its Suitability to UK Farming and Waste Systems (Andersons)". 4 October 2008. Archived from the original on 4 October 2008. Retrieved 2 January 2023.
  54. ^ "BIOGAS: No bull, manure can power your farm." Farmers Guardian (25 September 2009): 12. General OneFile. Gale.
  55. ^ Nagel F (2008). Electricity from wood through the combination of gasification and solid oxide fuel cells (PhD thesis). Swiss Federal Institute of Technology Zurich. Archived from the original on 13 March 2011.
  56. ^ a b "Biofuel from Algae: The Pros and Cons of Pond Scum". Thomasnet®. Archived from the original on 6 April 2020. Retrieved 25 October 2020.
  57. ^ "Biomass - Offshore wind farms = seaweed = biofuel". Renewable Energy Magazine, at the heart of clean energy journalism. 14 September 2020. Archived from the original on 27 July 2020. Retrieved 16 October 2020.
  58. ^ Greenwell HC, Laurens LM, Shields RJ, Lovitt RW, Flynn KJ (May 2010). "Placing microalgae on the biofuels priority list: a review of the technological challenges". Journal of the Royal Society, Interface. 7 (46): 703–726. doi:10.1098/rsif.2009.0322. PMC 2874236. PMID 20031983.
  59. ^ Ajayebi, Atta; Gnansounou, Edgard; Kenthorai Raman, Jegannathan (1 December 2013). "Comparative life cycle assessment of biodiesel from algae and jatropha: A case study of India". Bioresource Technology. 150: 429–437. doi:10.1016/j.biortech.2013.09.118. ISSN 0960-8524.
  60. ^ Yang J, Xu M, Zhang X, Hu Q, Sommerfeld M, Chen Y (January 2011). "Life-cycle analysis on biodiesel production from microalgae: water footprint and nutrients balance" (PDF). Bioresource Technology. 102 (1): 159–165. doi:10.1016/j.biortech.2010.07.017. PMID 20675125. Archived from the original (PDF) on 27 February 2012.
  61. ^ Cornell CB (29 March 2008). "First Algae Biodiesel Plant Goes Online: 1 April 2008". Gas 2.0. Archived from the original on 18 June 2019. Retrieved 10 June 2008.
  62. ^ Dinh LT, Guo Y, Mannan MS (2009). "Sustainability evaluation of biodiesel production using multicriteria decision-making". Environmental Progress & Sustainable Energy. 28: 38–46. doi:10.1002/ep.10335. S2CID 111115884.
  63. ^ Demirbas AH (2011). "Biodiesel from oilgae, biofixation of carbon dioxide by microalgae: A solution to pollution problems". Applied Energy. 88 (10): 3541–3547. doi:10.1016/j.apenergy.2010.12.050. hdl:11503/1330.
  64. ^ Demirbas AH (2009). "Inexpensive oil and fats feedstocks for production of biodiesel". Energy Education Science and Technology Part A: Energy Science and Research. 23: 1–13.
  65. ^ Wesoff E (19 April 2017). "Hard Lessons From the Great Algae Biofuel Bubble". Archived from the original on 5 July 2017. Retrieved 5 August 2017.
  66. ^ Lü J, Sheahan C, Fu P (2011). "Metabolic engineering of algae for fourth generation biofuels production". Energy & Environmental Science. 4 (7): 2451. doi:10.1039/c0ee00593b. ISSN 1754-5692.
  67. ^ a b c Aro EM (January 2016). "From first generation biofuels to advanced solar biofuels". Ambio. 45 (Supplement 1): S24–S31. doi:10.1007/s13280-015-0730-0. PMC 4678123. PMID 26667057.
  68. ^ a b Abdullah B, Muhammad SA, Shokravi Z, Ismail S, Kassim KA, Mahmood AN, Aziz MM (June 2019). "Fourth generation biofuel: A review on risks and mitigation strategies". Renewable and Sustainable Energy Reviews. 107: 37–50. doi:10.1016/j.rser.2019.02.018. S2CID 116245776.
  69. ^ a b "Transport biofuels – Renewables 2022 – Analysis". IEA. Retrieved 30 January 2023.
  70. ^ a b "Biofuels – Analysis". IEA. Retrieved 30 January 2023.
  71. ^ Rodionova, M.V.; Poudyal, R.S.; Tiwari, I.; Voloshin, R.A.; Zharmukhamedov, S.K.; Nam, H.G.; Zayadan, B.K.; Bruce, B.D.; Hou, H.J.M.; Allakhverdiev, S.I. (2017). "Biofuel production: Challenges and opportunities". International Journal of Hydrogen Energy. 42 (12): 8450–8461. doi:10.1016/j.ijhydene.2016.11.125.
  72. ^ Towards sustainable production and use of resources: Assessing Biofuels Archived 2016-05-13 at the Portuguese Web Archive, 2009, International Resource Panel, United Nations Environment Programme
  73. ^ a b c d Jeswani HK, Chilvers A, Azapagic A (November 2020). "Environmental sustainability of biofuels: a review". Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences. 476 (2243): 20200351. Bibcode:2020RSPSA.47600351J. doi:10.1098/rspa.2020.0351. PMC 7735313. PMID 33363439.
  74. ^ Lewandrowski J, Rosenfeld J, Pape D, Hendrickson T, Jaglo K, Moffroid K (25 March 2019). "The greenhouse gas benefits of corn ethanol – assessing recent evidence". Biofuels. Informa UK Limited. 11 (3): 361–375. doi:10.1080/17597269.2018.1546488. ISSN 1759-7269. S2CID 134824935.
  75. ^ Lark TJ, Hendricks NP, Smith A, Pates N, Spawn-Lee SA, Bougie M, et al. (March 2022). "Environmental outcomes of the US Renewable Fuel Standard". Proceedings of the National Academy of Sciences of the United States of America. 119 (9). Bibcode:2022PNAS..11901084L. doi:10.1073/pnas.2101084119. PMC 8892349. PMID 35165202.
  76. ^ "Food vs fuel: Ukraine war sharpens debate on use of crops for energy". Financial Times. 12 June 2022. Archived from the original on 10 December 2022.
  77. ^ "Guest view: Global hunger fight means no biofuel". Reuters. 6 June 2022.
  78. ^ "Cutting biofuels can help avoid global food shock from Ukraine war". New Scientist. 14 March 2022.
  79. ^ Antizar-Ladislao B, Turrion-Gomez JL (September 2008). "Second-generation biofuels and local bioenergy systems". Biofuels, Bioproducts and Biorefining. 2 (5): 455–469. doi:10.1002/bbb.97. S2CID 84426763.
  80. ^ Bryngemark E (December 2019). "Second generation biofuels and the competition for forest raw materials: A partial equilibrium analysis of Sweden". Forest Policy and Economics. 109: 102022. doi:10.1016/j.forpol.2019.102022. ISSN 1389-9341. S2CID 212954432.
  81. ^ a b Timothy Searchinger; et al. (29 February 2008). "Use of U.S. Croplands for Biofuels Increases Greenhouse Gases Through Emissions from Land-Use Change". Science. 319 (5867): 1238–1240. Bibcode:2008Sci...319.1238S. doi:10.1126/science.1151861. PMID 18258860. S2CID 52810681. Originally published online in Science Express on 7 February 2008 available here Archived 2009-12-11 at the Wayback Machine
  82. ^ a b Michael Wang; Zia Haq (14 March 2008). "Letter to Science about Searchinger et al. article" (PDF). Argonne National Laboratory. Archived from the original (PDF) on 15 February 2013. Retrieved 7 June 2009. The published version on Science Letters is included in Searchinger E-Letter responses 2008-08-12
  83. ^ a b Gnansounou; et al. (March 2008). "Accounting for indirect land-use changes in GHG balances of biofuels: Review of current approaches" (PDF). École Polytechnique Fédérale de Lausanne. Retrieved 7 June 2009. Working Paper REF. 437.101
  84. ^ Alexander E. Farrell (13 February 2008). "Better biofuels before more biofuels". San Francisco Chronicle. Retrieved 7 June 2009.
  85. ^ Donald Sawyer (27 May 2008). "Climate change, biofuels and eco-social impacts in the Brazilian Amazon and Cerrado". Philosophical Transactions of the Royal Society. 363 (1498): 1747–1752. doi:10.1098/rstb.2007.0030. PMC 2373893. PMID 18267903. Published on line 2008-02-11.
  86. ^ Naylor; et al. (November 2007). "The Ripple Effect: Biofuels, Food Security, and the Environment". Environment. Retrieved 7 June 2009.
  87. ^ Renton Righelato; Dominick V. Spracklen (17 August 2007). "Carbon Mitigation by Biofuels or by Saving and Restoring Forests?". Science. 317 (5840): 902. doi:10.1126/science.1141361. PMID 17702929. S2CID 40785300.

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