# Biofuel

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Fuel derived from biological sources

This article is about mainly liquid or gaseous fuels used for transport. For other applications, see [Bioenergy](/source/Bioenergy).

A sample of [biodiesel](/source/Biodiesel)

Part of a series on Renewable energy Biofuel Biogas Biomass Carbon-neutral fuel Crosswind kite power Geothermal energy Geothermal heating Geothermal power Hydroelectricity Run-of-the-river Hydropower Micro hydro Pico hydro Small hydro Marine current power Marine energy Ocean thermal Osmotic power Solar energy Solar power Sustainable biofuel Tidal power Tidal stream generator Wave power Wind power Nuclear power proposed as renewable energy Topics by country and territory Marketing and policy trends v t e

**Biofuel** is a [fuel](/source/Fuel) that is produced over a short time span from [biomass](/source/Biomass_(energy)), rather than by the very slow natural processes involved in the formation of [fossil fuels](/source/Fossil_fuel) such as oil.[1] Biofuel can be produced from plants or from agricultural, domestic or industrial [bio waste](/source/Biodegradable_waste).[2][3][4][5] Biofuels are mostly used for transportation, but can also be used for heating and electricity.[6]: 173[7] Biofuels (and [bioenergy](/source/Bioenergy) in general) are regarded as a [renewable energy](/source/Renewable_energy) source.[8]: 11 The use of biofuel has been subject to criticism regarding the "[food vs fuel](/source/Food_vs_fuel)" debate, varied assessments of their [sustainability](/source/Sustainable_biofuel), and ongoing [deforestation](/source/Deforestation) and [biodiversity loss](/source/Biodiversity_loss) as a result of biofuel production.[9]

In general, biofuels emit fewer [greenhouse gas emissions](/source/Greenhouse_gas_emissions) when burned in an engine and are generally considered [carbon-neutral fuels](/source/Carbon-neutral_fuel) as the carbon emitted has been captured from the atmosphere by the crops used in production.[10][11] However, [life-cycle assessments](/source/Life-cycle_assessment) of biofuels have shown large emissions associated with the potential [land-use change](/source/Land-use_change) required to produce additional biofuel feedstocks.[12][13] The outcomes of lifecycle assessments (LCAs) for biofuels are highly situational and dependent on many factors including the type of feedstock, production routes, data variations, and methodological choices.[14] Estimates about the climate impact from biofuels vary widely based on the methodology and exact situation examined.[12] Therefore, the [climate change mitigation](/source/Climate_change_mitigation) potential of biofuel varies considerably: in some scenarios biofuel emission levels are comparable to fossil fuels, and in other scenarios the use of biofuel results in [negative emissions](/source/Negative_emissions_technologies).

Global demand for biofuels is predicted to increase by 56% over 2022–2027.[15] By 2027 worldwide biofuel production is expected to supply 5.4% of the world's fuels for transport including 1% of aviation fuel.[16] Demand for [aviation biofuel](/source/Aviation_biofuel) is forecast to increase.[17][18] However some policy has been criticised for favoring ground transportation over aviation.[19]

The [IEA](/source/International_Energy_Agency) says that biofuel should particularly be used for applications which are difficult to electrify, such as shipping and aviation.[20] The two most common types of biofuel are [bioethanol](/source/Ethanol#Fuel) and [biodiesel](/source/Biodiesel). The United States is the largest producer of bioethanol, while the EU is the largest producer of biodiesel. Meanwhile, Brazil produces and uses large amounts of bioethanol in vehicles,[21] including in some [flex-fuel](/source/Flexible-fuel_vehicle) cars exclusively available in Brazil.[22] The energy content in the global production of bioethanol and biodiesel is 2.2 and 1.8 [EJ](/source/Joule#Multiples) per year, respectively.[23]

## Terminology

See also: [Biomass (energy) § Terminology](/source/Biomass_(energy)#Terminology)

Types and generation of biofuels

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](/source/Molasses) and [bagasse](/source/Bagasse)."[6]: 173

Other publications reserve the term biofuel for *liquid* or *gaseous* fuels, used for transportation.[7]

The [IPCC Sixth Assessment Report](/source/IPCC_Sixth_Assessment_Report) defines *biofuel* as "A fuel, generally in liquid form, produced from [biomass](/source/Biomass_(energy)). Biofuels include [bioethanol](/source/Bioethanol) from sugarcane, sugar beet or maize, and [biodiesel](/source/Biodiesel) from canola or soybeans.".[24]: 1795 It goes on to define *biomass* in this context as "organic material excluding the material that is fossilized or embedded in geological formations".[24]: 1795 This means that [coal](/source/Coal) or other [fossil fuels](/source/Fossil_fuel) is not a form of biomass in this context.

Bioethanol is an [alcohol](/source/Alcohol_(chemistry)) made by [fermentation](/source/Ethanol_fermentation), mostly from [carbohydrates](/source/Carbohydrate) produced in [sugar](/source/Sugar) or [starch](/source/Starch) crops such as [maize](/source/Maize), [sugarcane](/source/Sugarcane), or [sweet sorghum](/source/Sweet_sorghum). [Cellulosic biomass](/source/Cellulose), derived from non-food sources, such as trees and grasses, is also being developed as a [feedstock](/source/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](/source/Gasoline) [additive](/source/Fuel_additive) to increase octane ratings and improve vehicle emissions.

Biodiesel is produced from oils or fats using [transesterification](/source/Transesterification). It can be used as a fuel for vehicles in its pure form (B100), but it is usually used as a [diesel](/source/Diesel_fuel) additive to reduce levels of particulates, [carbon monoxide](/source/Carbon_monoxide), and [hydrocarbons](/source/Hydrocarbon) from diesel-powered vehicles.[25]

### Conventional biofuels (first generation)

*First-generation biofuels* (also denoted as "conventional biofuels") are made from food crops grown on arable land.[26][27]: 447 The crop's sugar, starch, or oil content is converted into [biodiesel](/source/Biodiesel) or [ethanol](/source/Ethanol), using [transesterification](/source/Transesterification), or yeast fermentation.[28]

### Advanced biofuels

To avoid a "[food versus fuel](/source/Food_vs._fuel)" dilemma, [second-generation biofuels](/source/Second-generation_biofuels) and third-generation biofuels (also called [advanced biofuels](/source/Advanced_Biofuels) or [sustainable biofuels](/source/Sustainable_biofuel) or drop-in biofuels) are made from feedstocks which do not directly compete with food or feed crop such as waste products and energy crops.[29] A wide range of renewable residue feedstocks such as those derived from agriculture and forestry activities like rice straw, rice husk, wood chips, and sawdust can be used to produce advanced biofuels through biochemical and thermochemical processes.[27]: 448g[30]

The feedstock used to make the fuels either grow on [arable land](/source/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](/source/Jatropha), waste vegetable oil, municipal solid waste and so forth.[31]

## Types

### Liquid

#### Ethanol

Main article: [Ethanol fuel](/source/Ethanol_fuel)

Biologically produced [alcohols](/source/Alcohols), most commonly ethanol, and less commonly [propanol](/source/Propan-1-ol) and [butanol](/source/Butanol_fuel), are produced by the action of [microorganisms](/source/Microorganism) and [enzymes](/source/Enzyme) through the fermentation of sugars or starches (easiest to produce) or cellulose (more difficult to produce).[32] The IEA estimates that ethanol production used 20% of sugar supplies and 13% of corn supplies in 2021.[33]

Ethanol fuel is the most common biofuel worldwide, particularly [in Brazil](/source/Ethanol_fuel_in_Brazil). [Alcohol fuels](/source/Alcohol_fuel) are produced by fermentation of sugars derived from [wheat](/source/Wheat), [corn](/source/Maize), [sugar beets](/source/Sugar_beet), [sugar cane](/source/Sugar_cane), [molasses](/source/Molasses) and any sugar or starch from which [alcoholic beverages](/source/Alcoholic_beverage) such as [whiskey](/source/Whiskey), can be made (such as [potato](/source/Potato) and [fruit](/source/Fruit) waste, etc.). Production methods used are [enzyme digestion](/source/Digestive_enzyme) (to release sugars from stored starches), fermentation of the sugars, [distillation](/source/Distillation) and drying. The distillation process requires significant energy input to generate heat. Heat is sometimes generated with unsustainable [natural gas](/source/Natural_gas) fossil fuel, but cellulosic biomass such as [bagasse](/source/Bagasse) is the most common fuel in Brazil, while pellets, wood chips and also [waste heat](/source/Waste_heat) are more common in Europe. Corn-to-ethanol and other food stocks has led to the development of [cellulosic ethanol](/source/Cellulosic_ethanol).[34] Ethanol fuel can be combined with gasoline to create a more environmentally friendly fuel though there are more viable substitutions to gasoline such as [Butanol](/source/Butanol_fuel).[35]

#### Other biofuels

[Methanol](/source/Methanol) is currently produced from [natural gas](/source/Natural_gas), a [non-renewable](/source/Non-renewable) fossil fuel. In the future it is hoped to be produced from biomass as [biomethanol](/source/Biomethanol). This is technically feasible, but the production is currently being postponed for concerns that the economic viability is still pending.[36] The [methanol economy](/source/Methanol_economy) is an alternative to the [hydrogen economy](/source/Hydrogen_economy) to be contrasted with today's [hydrogen](/source/Hydrogen) production from natural gas.

[Butanol](/source/Butanol_fuel) (C 4H 9OH) is formed by [ABE fermentation](/source/Clostridium_acetobutylicum) (acetone, butanol, ethanol) and experimental modifications of the process show potentially high [net energy gains](/source/Net_energy_gain) with [biobutanol](/source/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),[37] is less corrosive and less water-soluble than ethanol, and could be distributed via existing infrastructures. *[Escherichia coli](/source/Escherichia_coli)* strains have also been successfully engineered to produce butanol by modifying their [amino acid metabolism](/source/Protein_metabolism).[38] One drawback to butanol production in *E. coli* remains the high cost of [nutrient rich media](/source/Growth_medium), however, recent work has demonstrated *E. coli* can produce butanol with minimal nutritional supplementation.[39] Biobutanol is sometimes called [biogasoline](/source/Biogasoline), which is incorrect as it is chemically different, being an alcohol and not a hydrocarbon like gasoline.

#### Biodiesel

Biofuel pumps, 2010

Main article: [Biodiesel](/source/Biodiesel)

Further information: [Biodiesel around the world](/source/Biodiesel_around_the_world)

Biodiesel is the most common biofuel in Europe. It is produced from oils or fats using [transesterification](/source/Transesterification) and is a liquid similar in composition to fossil/mineral diesel. Chemically, it consists mostly of fatty acid methyl (or ethyl) esters ([FAMEs](/source/Fatty_acid_methyl_ester)).[40] Feedstocks for biodiesel include animal fats, vegetable oils, [soy](/source/Soy), [rapeseed](/source/Rapeseed), [jatropha](/source/Jatropha_curcas), [mahua](/source/Madhuca_longifolia), [mustard](/source/Mustard_plant), [flax](/source/Flax), [sunflower](/source/Sunflower), [palm oil](/source/Palm_oil), [hemp](/source/Hemp), [field pennycress](/source/Thlaspi_arvense), *[Pongamia pinnata](/source/Pongamia_pinnata)* and [algae](/source/Algae_fuel). Pure biodiesel (B100, also known as "neat" biodiesel) currently reduces emissions with up to 60% compared to diesel Second generation B100.[41] As of 2020[\[update\]](https://en.wikipedia.org/w/index.php?title=Biofuel&action=edit), researchers at Australia's [CSIRO](/source/CSIRO) have been studying [safflower](/source/Safflower) oil as an engine [lubricant](/source/Lubricant), and researchers at [Montana State University](/source/Montana_State_University)'s Advanced Fuels Center in the US have been studying the oil's performance in a large [diesel engine](/source/Diesel_engine), with results described as a "breakthrough".[42]

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 occur during wintertime utilization, since the fuel becomes somewhat more [viscous](/source/Viscosity) at lower temperatures, depending on the feedstock used.[43]

Electronically controlled '[common rail](/source/Common_rail)' and '[Unit Injector](/source/Unit_Injector)' type systems from the late 1990s onwards can 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 designed to run on B100 without altering the engine itself, although this depends on the [fuel rail](/source/Fuel_rail) design. Since biodiesel is an effective [solvent](/source/Solvent) and cleans residues deposited by mineral diesel, [engine filters](/source/Oil_filter) 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](/source/Combustion_chamber) of carbon deposits, helping to maintain efficiency.

Biodiesel is an [oxygenated](/source/Oxygenate) fuel, meaning it contains a reduced amount of carbon and higher hydrogen and oxygen content than fossil diesel. This improves the [combustion](/source/Combustion) of biodiesel and reduces the particulate emissions from unburnt carbon. However, using pure biodiesel may increase NOx-emissions[44] Biodiesel is also safe to handle and transport because it is non-toxic and [biodegradable](/source/Biodegradable), and has a high [flash point](/source/Flash_point) of about 300 °F (148 °C) compared to petroleum diesel fuel, which has a flash point of 125 °F (52 °C).[45]

In many European countries, a 5% biodiesel blend is widely used and is available at thousands of gas stations.[46][47] In France, biodiesel is incorporated at a rate of 8% in the fuel used by all French diesel vehicles.[48] [Avril Group](/source/Avril_Group) produces under the brand [Diester](/source/Diester), a fifth of 11 million tons of biodiesel consumed annually by the [European Union](/source/European_Union).[49] It is the leading European producer of biodiesel.[48]

#### Green diesel

Main article: [Biodiesel production](/source/Biodiesel_production)

[Green diesel](/source/Hydrotreated_vegetable_oil) can be produced from a combination of biochemical and thermochemical processes. Conventional green diesel is produced through hydroprocessing biological oil feedstocks, such as vegetable oils and animal fats.[50][51] Recently, it is produced using series of thermochemical processes such as pyrolysis and hydroprocessing. In the thermochemical route, syngas produced from gasification, bio-oil produced from pyrolysis or biocrude produced from hydrothermal liquefaction is upgraded to green diesel using hydroprocessing.[52][53][54] Hydroprocessing is the process of using hydrogen to reform a molecular structure. For example, [hydrocracking](/source/Hydrocracking) which is a widely used hydroprocessing technique in refineries is used at elevated temperatures and pressure in the presence of a catalyst to break down larger [molecules](/source/Molecules), such as those found in [vegetable oils](/source/Vegetable_oil), into shorter [hydrocarbon](/source/Hydrocarbon) chains used in [diesel](/source/Diesel_fuel) engines.[55] Green diesel may also be called renewable diesel, drop-in biodiesel, hydrotreated vegetable oil (HVO fuel)[55] or hydrogen-derived renewable diesel.[51] Unlike biodiesel, green diesel has exactly the same chemical properties as petroleum-based diesel.[55][56] 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](/source/Petroleum).[51] Gasoline versions are also being developed.[57] Green diesel is being developed in [Louisiana](/source/Louisiana) and [Singapore](/source/Singapore) by [ConocoPhillips](/source/ConocoPhillips), [Neste Oil](/source/Neste_Oil), [Valero](/source/Valero_Energy_Corporation), Dynamic Fuels, and [Honeywell UOP](/source/UOP_LLC)[51][58] as well as Preem in Gothenburg, Sweden, creating what is known as Evolution Diesel.[59]

#### Straight vegetable oil

A biofuel truck in 2009[60]

Main article: [Vegetable oil fuel](/source/Vegetable_oil_fuel)

Straight unmodified [edible](/source/Eating) 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.[33]

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](/source/Hydrogenated) to give a diesel substitute.[61] The resulting product is a straight-chain hydrocarbon with a high [cetane number](/source/Cetane_number), low in [aromatics](/source/Aromatics) and [sulfur](/source/Sulfur) and does not contain oxygen. [Hydrogenated oils](/source/Hydrogenated_oil) 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.[62]

#### Biogasoline

Main article: [Biogasoline](/source/Biogasoline)

Biogasoline can be produced biologically and thermochemically. Using biological methods, a study led by Professor Lee Sang-yup at the Korea Advanced Institute of Science and Technology ([KAIST](/source/KAIST)) and published in the international science journal *[Nature](/source/Nature_(journal))* 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.[63] The thermochemical approach of producing biogasoline are similar to those used to produce biodiesel.[52][53][54] Biogasoline may also be called drop-in gasoline or renewable gasoline.

#### Bioethers

[Neat ethanol](/source/Common_ethanol_fuel_mixtures#E100) on the left (A), [gasoline](/source/Gasoline) on the right (G) at a [filling station](/source/Filling_station) in Brazil in 2008

Bioethers (also referred to as fuel [ethers](/source/Ether) or oxygenated fuels) are cost-effective [compounds](/source/Chemical_compound) that act as [octane rating](/source/Octane_rating) enhancers. "Bioethers are produced by the reaction of reactive iso-olefins, such as iso-butylene, with bioethanol."[64][*[attribution needed](https://en.wikipedia.org/wiki/Wikipedia:Attribution_needed)*] Bioethers are created from wheat or sugar beets, and also be produced from the waste glycerol that results from the production of biodiesel.[65] They also enhance [engine](/source/Engine) performance, while significantly reducing engine wear and [toxic](/source/Toxic) [exhaust emissions](/source/Exhaust_gas). By greatly reducing the amount of ground-level [ozone](/source/Ozone) emissions, they contribute to improved air quality.[67][68]

In transportation fuel there are six ether additives: dimethyl ether (DME), [diethyl ether](/source/Diethyl_ether) (DEE), [methyl *tert*-butyl ether](/source/Methyl_tert-butyl_ether) (MTBE), [ethyl *tert*-butyl ether](/source/Ethyl_tert-butyl_ether) (ETBE), [*tert*-amyl methyl ether](/source/Tert-Amyl_methyl_ether) (TAME), and [*tert*-amyl ethyl ether](/source/Tert-Amyl_ethyl_ether) (TAEE).[69]

The European Fuel Oxygenates Association identifies MTBE and ETBE as the most commonly used ethers in fuel to replace [lead](/source/Tetraethyllead). Ethers were introduced in Europe in the 1970s to replace the highly toxic compound.[70] Although Europeans still use bioether additives, the U.S. [Energy Policy Act of 2005](/source/Energy_Policy_Act_of_2005) lifted a requirement for [reformulated gasoline](/source/Reformulated_gasoline) to include an oxygenate, leading to less MTBE being added to fuel.[71] Although bioethers are likely to replace ethers produced from petroleum in the UK, it is highly unlikely they will become a fuel in and of itself due to the low energy density.[72]

#### Aviation biofuel

This section is an excerpt from [Aviation biofuel](/source/Aviation_biofuel).[[edit](https://en.wikipedia.org/w/index.php?title=Aviation_biofuel&action=edit)]

Refueling an [Airbus A320](/source/Airbus_A320) with biofuel in 2011

An [aviation biofuel](/source/Aviation_biofuel) (also known as bio-jet fuel,[73] sustainable aviation fuel (SAF), or bio-aviation fuel (BAF)[74]) is a biofuel used to power [aircraft](/source/Aircraft). The [International Air Transport Association](/source/International_Air_Transport_Association) (IATA) considers it a key element in reducing the [environmental impact of aviation](/source/Environmental_impact_of_aviation).[75] Aviation biofuel is used to [decarbonize](/source/Low-carbon_economy) medium and long-haul air travel. These types of travel generate the most emissions. Synthetic paraffinic kerosene (SPK) refers to any non-petroleum-based fuel designed to replace kerosene [jet fuel](/source/Jet_fuel), which is often, but not always, made from biomass.

Biofuels are [biomass](/source/Biomass)-derived fuels from plants, animals, or waste; depending on which type of biomass is used, they could lower CO2 emissions by 20–98% compared to [conventional jet fuel](/source/Jet_A1).[76] The first test flight using blended biofuel was in 2008, and in 2011, blended fuels with 50% biofuels were allowed on commercial flights. In 2023 SAF production was 600 million liters, representing 0.2% of global jet fuel use.[77] By 2024, SAF production was to increase to 1.3 billion liters (1 million tonnes), representing 0.3% of global jet fuel consumption and 11% of global renewable fuel production.[78] This increase came as major US production facilities delayed their ramp-up until 2025, having initially been expected to reach 1.9 billion liters.

Aviation biofuel can be produced from plant or animal sources such as *[Jatropha](/source/Jatropha)*, [algae](/source/Algae), [tallows](/source/Tallows), waste oils, [palm oil](/source/Palm_oil), [Babassu](/source/Babassu_oil), and *[Camelina](/source/Camelina)* (bio-SPK); from solid [biomass](/source/Biomass) using [pyrolysis](/source/Pyrolysis) processed with a [Fischer–Tropsch process](/source/Fischer%E2%80%93Tropsch_process) (FT-SPK); with an [alcohol](/source/Alcohol_(chemistry))-to-jet (ATJ) process from waste fermentation; or from [synthetic biology](/source/Synthetic_biology) through a [solar reactor](/source/Chemical_reactor). Small piston engines can be modified to burn [ethanol](/source/Ethanol).

[Sustainable biofuels](/source/Sustainable_biofuel) are an alternative to [electrofuels](/source/Electrofuels).[79] Sustainable aviation fuel is certified as being [sustainable](/source/Sustainable) by a third-party organisation.

SAF technology faces significant challenges due to feedstock constraints. The oils and fats known as hydrotreated esters and fatty acids (Hefa), crucial for SAF production, are in limited supply as demand increases. Although advanced [e-fuels](/source/Electrofuel) technology, which combines waste CO2 with [clean hydrogen](/source/Green_hydrogen), presents a promising solution, it is still under development and comes with high costs. To overcome these issues, SAF developers are exploring more readily available feedstocks such as [woody biomass](/source/Lignocellulosic_biomass) and agricultural and municipal waste, aiming to produce lower-carbon jet fuel more sustainably and efficiently.[80][81]

### Gaseous

#### Biogas and biomethane

Biogas plant in 2007

Main article: [Biogas](/source/Biogas)

Biogas is a mixture composed primarily of [methane](/source/Methane) and [carbon dioxide](/source/Carbon_dioxide) produced by the process of [anaerobic digestion](/source/Anaerobic_digestion) of [organic material](/source/Organic_material) by [micro-organisms](/source/Micro-organisms). Other trace components of this mixture includes water vapor, [hydrogen sulfide](/source/Hydrogen_sulfide), siloxanes, hydrocarbons, ammonia, oxygen, carbon monoxide, and nitrogen.[82][83] It can be produced either from [biodegradable waste](/source/Biodegradable_waste) materials or by the use of [energy crops](/source/Energy_crop) fed into [anaerobic digesters](/source/Anaerobic_digester) to supplement gas yields. The solid byproduct, [digestate](/source/Digestate), can be used as a biofuel or a fertilizer. When CO2 and other impurities are removed from biogas, it is called [biomethane](/source/Biomethane). The CO2 can also be combined with hydrogen in [methanation](/source/Methanation) to form more methane.

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

In Sweden, "[waste-to-energy](/source/Waste-to-energy)" power plants capture methane biogas from garbage and use it to power transport systems.[84] Farmers can produce biogas from cattle [manure](/source/Manure) via anaerobic digesters.[85]

#### Syngas

Main article: [Gasification](/source/Gasification)

[Syngas](/source/Syngas), a mixture of [carbon monoxide](/source/Carbon_monoxide), [hydrogen](/source/Hydrogen) and various hydrocarbons, is produced by partial combustion of biomass (combustion with an amount of [oxygen](/source/Oxygen) that is not sufficient to convert the biomass completely to carbon dioxide and water).[62] Before partial combustion the biomass is dried and sometimes [pyrolysed](/source/Pyrolysis). 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](/source/Turbines) or high-temperature fuel cells.[86] The [wood gas generator](/source/Wood_gas_generator), a wood-fueled gasification reactor, can be connected to an internal combustion engine.

Syngas can be used to produce [methanol](/source/Methanol), [dimethyl ether](/source/Dimethyl_ether) and [hydrogen](/source/Hydrogen), or converted via the [Fischer–Tropsch process](/source/Fischer%E2%80%93Tropsch_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](/source/Biochar), but results in syngas polluted with [tar](/source/Tar).

### Solid

Main article: [Solid fuel § Biomass](/source/Solid_fuel#Biomass)

The term "biofuels" is also used for [solid fuels](/source/Solid_fuel) that are made from biomass, even though this is less common.[7]

## Research into other types

### Algae-based biofuels

Main articles: [Algaculture](/source/Algaculture) and [Algae fuel](/source/Algae_fuel)

Algae can be produced in ponds or tanks on land, and out at sea.[87][88] Algal fuels have high yields,[89] a high [ignition point](/source/Flash_point),[90] can be grown with minimal impact on [fresh water](/source/Fresh_water) resources,[91][92][93] can be produced using saline water and [wastewater](/source/Wastewater), and are [biodegradable](/source/Biodegradable) and relatively harmless to the environment if spilled.[94][95] However, 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.[87][96]

By 2017, due to economic considerations, most efforts to produce fuel from algae have been abandoned or changed to other applications.[97]

Third and fourth-generation biofuels also include biofuels that are produced by bioengineered organisms i.e. algae and cyanobacteria.[98] Algae and cyanobacteria will use water, carbon dioxide, and solar energy to produce biofuels.[98] 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.[98] 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.[99] The disadvantages include the cost of cultivating the biofuel-producing organisms being very high.[99] Also, current methods of using algae often have worse environmental impacts than using other crops.[100]

Recent research highlights that the transition to sustainable energy is reliant on the widespread adoption of third- and fourth-generation biofuels, which utilize non-food sources such as algae and incorporate advanced processes like artificial photosynthesis. These alternatives are essential for climate change mitigation because they significantly reduce the land-use competition and sustainability risks associated with earlier biofuel generations.[101]

### Electrofuels and solar fuels

[Electrofuels](/source/Electrofuel)[*[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed)*] and [solar fuels](/source/Solar_fuel) may or may not be biofuels, depending on whether they contain biological elements. [Electrofuels](/source/Electrofuel) are made by storing [electrical energy](/source/Electrical_energy) in the chemical bonds of liquids and gases. The primary targets are [butanol](/source/Butanol), biodiesel, and [hydrogen](/source/Hydrogen_fuel), but include other alcohols and carbon-containing gases such as [methane](/source/Methane) and [butane](/source/Butane). A solar fuel is a synthetic chemical [fuel](/source/Fuel) produced from solar energy. Light is converted to [chemical energy](/source/Chemical_energy), typically by reducing [protons](/source/Protons) to [hydrogen](/source/Hydrogen), or [carbon dioxide](/source/Carbon_dioxide) to [organic compounds](/source/Organic_compounds).[102]

## Bio-digesters

A bio-digester is a mechanized toilet that uses decomposition and sedimentation to turn human waste into a renewable fuel called biogas. Biogas can be made from substances like agricultural waste and sewage.[103][104] The bio-digester uses a process called anaerobic digestion to produce biogas. Anaerobic digestion uses a chemical process to break down organic matter with the use of microorganisms in the absence of oxygen to produce biogas.[105] The processes involved in anaerobic respiration are hydrolysis, [acidogenesis](/source/Acidogenesis), [acetogenesis](/source/Acetogenesis), and [methanogenesis](/source/Methanogenesis).[106]

## Extent of production and use

Biofuel production

Biofuel production by region

Global biofuel production was 81 [Mtoe](/source/Million_Tonnes_of_Oil_Equivalent) in 2017 which represented an annual increase of about 3% compared to 2010.[8]: 12 In 2017, the US was the largest biofuel producer in the world producing 37 Mtoe, followed by Brazil and South America at 23 Mtoe and Europe (mainly Germany) at 12 Mtoe.[8]: 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](/source/Renewable_energy)."[8]: 11

In 2021, worldwide biofuel production provided 4.3% of the world's fuels for transport, including a very small amount of [aviation biofuel](/source/Aviation_biofuel).[16] By 2027, worldwide biofuel production is expected to supply 5.4% of the world's fuels for transport including 1% of aviation fuel.[16]

The US, Europe, Brazil and Indonesia are driving the majority of biofuel consumption growth. This demand for biodiesel, renewable diesel and biojet fuel is projected to increase by 44% (21 billion litres) over 2022-2027.[107]

## Issues

Wheat fields in the USA: wheat is grown for food but also for biofuel production.

This section is an excerpt from [Issues relating to biofuels](/source/Issues_relating_to_biofuels).[[edit](https://en.wikipedia.org/w/index.php?title=Issues_relating_to_biofuels&action=edit)]

[Issues relating to biofuel](/source/Issues_relating_to_biofuels) are social, economic, environmental and technical problems that may arise from biofuel production and use. Social and economic issues include the "[food vs fuel](/source/Food_vs_fuel)" debate and the need to develop responsible policies and economic instruments to ensure [sustainable biofuel](/source/Sustainable_biofuel) production. Farming for biofuels feedstock can be detrimental to the environment if not done sustainably. Environmental concerns include [deforestation](/source/Deforestation), [biodiversity loss](/source/Biodiversity_loss) and [soil erosion](/source/Soil_erosion) as a result of land clearing for biofuels agriculture. While biofuels can contribute to reduction in global [carbon emissions](/source/Carbon_emissions), [indirect land use change](/source/Indirect_land_use_change_impacts_of_biofuels) for biofuel production can have the inverse effect. Technical issues include possible modifications necessary to run the engine on biofuel, as well as [energy balance](/source/Energy_returned_on_energy_invested) and efficiency.

The [International Resource Panel](/source/International_Resource_Panel) outlined the wider and interrelated factors that need to be considered when deciding on the relative merits of pursuing one biofuel over another.[108] The IRP concluded that not all biofuels perform equally in terms of their effect on climate, [energy security](/source/Energy_security) and ecosystems, and suggested that environmental and social effects need to be assessed throughout the entire life-cycle.

### Environmental impacts

Further information: [Sustainable biofuels](/source/Sustainable_biofuels)

[Deforestation in Indonesia](/source/Deforestation_in_Indonesia), to make way for an [oil palm](/source/Oil_palm) plantation.[109]

Estimates about the climate impact from biofuels vary widely based on the methodology and exact situation examined.[12]

In general, biofuels emit fewer [greenhouse gas emissions](/source/Greenhouse_gas_emissions) when burned in an engine and are generally considered [carbon-neutral fuels](/source/Carbon-neutral_fuel) as the carbon they emit has been [captured](/source/Carbon_sequestration) from the atmosphere by the crops used in biofuel production.[10] They can have greenhouse gas emissions ranging from as low as -127.1 gCO2eq per MJ when carbon capture is incorporated into their production to those exceeding 95 gCO2eq per MJ when [land-use change](/source/Land-use_change) is significant.[53][54] Several factors are responsible for the variation in emission numbers of biofuel, such as feedstock and its origin, fuel production technique, system boundary definitions, and energy sources.[54] However, many government policies, such as those by the European Union and the UK, require that biofuels have at least 65% greenhouse gas emissions savings (or 70% if it is renewable fuels of non-biological origins) relative to fossil fuels.[110][111]

[Life-cycle assessments](/source/Life-cycle_assessment) of first-generation biofuels have shown large emissions associated with the potential [land-use change](/source/Land-use_change) required to produce additional biofuel feedstocks.[12][13] If no land-use change is involved, first-generation biofuels can—on average—have lower emissions than fossil fuels.[12] However, biofuel production can compete with food crop production. Up to 40% of corn produced in the United States is used to make ethanol[112] and worldwide 10% of all grain is turned into biofuel.[113] A 50% reduction in grain used for biofuels in the US and Europe would replace all of [Ukraine](/source/Ukraine)'s grain exports.[114] Several studies have shown that reductions in emissions from biofuels are achieved at the expense of other impacts, such as [acidification](/source/Ocean_acidification), [eutrophication](/source/Eutrophication), [water footprint](/source/Water_footprint) and [biodiversity loss](/source/Biodiversity_loss).[12]

Second-generation biofuels are thought to increase environmental sustainability since the non-food part of plants is being used to produce second-generation biofuels instead of being disposed of.[115] But the use of second-generation biofuels increases the competition for lignocellulosic biomass, increasing the cost of these biofuels.[116]

In theory, third-generation biofuels, produced from algae, shouldn't harm the environment more than first- or second-generation biofuels due to lower changes in land use and the fact that they do not require pesticide use for production.[117] When looking at the data however, it has been shown that the environmental cost to produce the infrastructure and energy required for third generation biofuel production, are higher than the benefits provided from the biofuels use.[118][119]

The [European Commission](/source/European_Commission) has officially approved a measure to phase out [palm oil](/source/Palm_oil)-based biofuels by 2030.[120][121] Unsustainable palm oil agriculture has caused significant environmental and social problems, including deforestation and pollution.

The production of biofuels can be very energy intensive, which, if generated from non-renewable sources, can heavily mitigate the benefits gained through biofuel use. A solution proposed to solve this issue is to supply biofuel production facilities with excess nuclear energy, which can supplement the power provided by fossil fuels.[122] This can provide a carbon inexpensive solution to help reduce the environmental impacts of biofuel production.

### Indirect land use change impacts of biofuels

This section is an excerpt from [Indirect land use change impacts of biofuels](/source/Indirect_land_use_change_impacts_of_biofuels).[[edit](https://en.wikipedia.org/w/index.php?title=Indirect_land_use_change_impacts_of_biofuels&action=edit)]

This article needs to be updated. Please help update this article to reflect recent events or newly available information. (August 2021)

[Brazilian cerrado](/source/Cerrado)

[Amazon rainforest](/source/Amazon_rainforest)

The [indirect land use change impacts of biofuels](/source/Indirect_land_use_change_impacts_of_biofuels), also known as ILUC or iLUC (pronounced as i-luck), relates to the [unintended consequence](/source/Spillover_(economics)) of releasing more [carbon emissions](/source/Carbon_emissions) due to [land-use changes](/source/Land_use%2C_land-use_change_and_forestry) around the world induced by the expansion of croplands for [ethanol](/source/Ethanol_fuel) or [biodiesel](/source/Biodiesel) production in response to the increased global demand for biofuels.[123][124]

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](/source/Rainforest) and [grasslands](/source/Grassland), store carbon in their soil and [biomass](/source/Biomass) as plants grow each year, clearance of wilderness for new farms translates to a net increase in [greenhouse gas emissions](/source/Greenhouse_gas_emissions). Due to this [off-site change in the carbon stock](/source/Carbon_leakage) of the soil and the biomass, indirect land use change has consequences in the [greenhouse gas](/source/Greenhouse_gas) (GHG) balance of a biofuel.[123][124][125][126]

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](/source/Food_vs._fuel), [land tenure](/source/Land_tenure), worker migration, and community and cultural stability.[125][127][128][129]

## See also

- [Renewable energy portal](https://en.wikipedia.org/wiki/Portal:Renewable_energy)
- [Energy portal](https://en.wikipedia.org/wiki/Portal:Energy)
- [Biology portal](https://en.wikipedia.org/wiki/Portal:Biology)
- [Technology portal](https://en.wikipedia.org/wiki/Portal:Technology)
- [Ecology portal](https://en.wikipedia.org/wiki/Portal:Ecology)

- [Aviation biofuel](/source/Aviation_biofuel)

- [Bioenergy Europe](/source/Bioenergy_Europe)

- [BioEthanol for Sustainable Transport](/source/BioEthanol_for_Sustainable_Transport)

- [Biofuels by region](/source/Biofuels_by_region)

- [Biofuels Center of North Carolina](/source/Biofuels_Center_of_North_Carolina)

- [Biogas powerplant](/source/Biogas_powerplant)

- [International Renewable Energy Agency](/source/International_Renewable_Energy_Agency)

- [List of biofuel companies and researchers](/source/List_of_biofuel_companies_and_researchers)

- [List of vegetable oils used for biofuel](/source/List_of_vegetable_oils#Oils_used_for_biofuel)

- [Renewable energy by country](/source/Renewable_energy_by_country)

- [Residue-to-product ratio](/source/Residue-to-product_ratio)

- [Sustainable aviation fuel](/source/Sustainable_aviation_fuel)

- [Sustainable transport](/source/Sustainable_transport)

- [Table of biofuel crop yields](/source/Table_of_biofuel_crop_yields)

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## External links

Look up ***[biofuel](https://en.wiktionary.org/wiki/Special:Search/biofuel)*** in Wiktionary, the free dictionary.

- [*Biofuels Journal*](http://www.future-science.com/loi/bfs)

- [Alternative Fueling Station Locator](http://www.eere.energy.gov/afdc/fuels/stations_locator.html) [Archived](https://web.archive.org/web/20080714060953/http://www.eere.energy.gov/afdc/fuels/stations_locator.html) 14 July 2008 at the [Wayback Machine](/source/Wayback_Machine) ([EERE](/source/EERE))

- [Towards Sustainable Production and Use of Resources: Assessing Biofuels](https://web.archive.org/web/20091122133933/http://www.unep.fr/scp/rpanel/pdf/Assessing_Biofuels_Full_Report.pdf) by the [United Nations Environment Programme](/source/United_Nations_Environment_Programme), October 2009.

- [Biofuels guidance for businesses, including permits and licences required](https://web.archive.org/web/20101229084204/http://www.netregs.gov.uk/netregs/94953.aspx) on [NetRegs](/source/NetRegs).gov.uk

- [How Much Water Does It Take to Make Electricity?](https://web.archive.org/web/20090210045405/http://www.spectrum.ieee.org/apr08/6182)—Natural gas requires the least water to produce energy, some biofuels the most, according to a new study.

- [International Conference on Biofuels Standards](https://web.archive.org/web/20080214115435/http://ec.europa.eu/energy/res/events/biofuels.htm) – European Union Biofuels Standardization

- [Biofuels from Biomass: Technology and Policy Considerations](http://web.mit.edu/professional/short-programs/courses/biofuels_biomass.html) Thorough overview from MIT

- [The Guardian news on biofuels](https://www.theguardian.com/environment/biofuels)

- [The US DOE Clean Cities Program](https://web.archive.org/web/20040515205329/http://www.eere.energy.gov/cleancities/) – links to the 87 US [Clean Cities](/source/Clean_Cities) coalitions, as of 2004.

- [Biofuels Factsheet](https://web.archive.org/web/20090419194948/http://css.snre.umich.edu/css_doc/CSS08-09.pdf) by the [University of Michigan](/source/University_of_Michigan)'s [Center for Sustainable Systems](http://css.snre.umich.edu/)

- [Learn Biofuels – Educational Resource for Students](http://www.learnbiofuels.org/what-are-biofuels)

v t e Bioenergy Biofuels Alcohol Algae Babassu oil Bagasse Biobutanol Biodiesel Biogas Biogasoline Bioliquids Biomass Cooking oil vegetable oil Ethanol cellulosic mixtures Methanol Stover corn Straw Water hyacinth Wood gas Energy from foodstock Camelina sativa Cassava Coconut oil Grape Hemp Maize Oat Palm oil Potato Rapeseed Rice Sorghum Soybean Sugar beet Sugarcane Sunflower Wheat Yam Non-food energy crops Arundo Big bluestem Camelina Chinese tallow Duckweed Jatropha curcas Miscanthus × giganteus Pongamia pinnata Salicornia Switchgrass Wood Technology Bioconversion of biomass to mixed alcohol fuels Bioenergy with carbon capture and storage Biomass heating systems Biorefinery Fischer–Tropsch process Industrial biotechnology Pellet fuel mill stove Sabatier reaction Thermal depolymerization Concepts Agflation Cellulosic ethanol commercialization Energy content of biofuel Energy crop Energy forestry Energy return on investment Food vs. fuel Issues relating to biofuels Sustainable biofuel Category

v t e Environmental technology General Appropriate technology Clean technology Climate smart agriculture Environmental design Environmental impact assessment Eco-innovation Ecotechnology Electric vehicle Energy recycling Environmental design Environmental impact assessment Environmental impact design Green building Green vehicle Environmentally healthy community design Public interest design Sustainability Sustainability science Sustainable (agriculture architecture design development food systems industries procurement refurbishment technology transport) Pollution Air pollution (control dispersion modeling) Industrial ecology Solid waste treatment Waste management Water (agricultural wastewater treatment industrial wastewater treatment sewage treatment waste-water treatment technologies water purification) Sustainable energy Efficient energy use Electrification Energy development Energy recovery Fuel (alternative fuel biofuel carbon-neutral fuel hydrogen technologies) List of energy storage projects Renewable energy commercialization transition Sector coupling Power-to-X Power-to-heat Power-to-gas Sustainable lighting Transportation (electric vehicle hybrid vehicle) Conservation Building (green insulation natural sustainable architecture New Urbanism New Classical) Conservation biology Ecoforestry Efficient energy use Energy conservation Energy recovery Energy recycling Environmental movement Environmental remediation Glass in green buildings Green computing Heat recovery ventilation High-performance buildings Land rehabilitation Nature conservation Permaculture Recycling Water heat recycling

v t e Climate change Overview Causes of climate change Effects of climate change Climate change mitigation Climate change adaptation By country and region Causes Overview Climate system Greenhouse effect (Carbon dioxide in the atmosphere of Earth) Scientific consensus on climate change Sources Deforestation Fossil fuel Greenhouse gases Greenhouse gas emissions Carbon accounting Carbon footprint Carbon leakage from agriculture from wetlands World energy supply and consumption History History of climate change policy and politics History of climate change science Svante Arrhenius James Hansen Charles David Keeling United Nations Climate Change conferences International Conference on Transitioning Away from Fossil Fuels Years in climate change 2019 2020 2021 2022 2023 2024 2025 2026 Effects and issues Physical Abrupt climate change Anoxic event Arctic methane emissions Arctic sea ice decline Atlantic meridional overturning circulation Drought Extreme weather Flood Coastal flooding Heat wave Marine Urban heat island Oceans acidification deoxygenation heat content sea surface temperature stratification temperature Ozone depletion Permafrost thaw Retreat of glaciers since 1850 Sea level rise Season creep Climate sensitivity Tipping points in the climate system Tropical cyclones Water cycle Wildfires Flora and fauna Biomes Mass mortality event Birds Extinction risk Forest dieback Invasive species Marine life Plant biodiversity Social and economic Agriculture Livestock Multi-breadbasket failure In the United States Children Cities Civilizational collapse Crime Depopulation of settlements Destruction of cultural heritage Disability Economic impacts U.S. insurance industry Fisheries Gender Health Infectious diseases Mental health In the United Kingdom In the Philippines Human rights Indigenous peoples Migration Poverty Psychological impacts Security and conflict Urban flooding Water scarcity Water security By country and region Africa Americas Antarctica Arctic Asia Australia Caribbean Europe Middle East and North Africa Small island countries by individual country Mitigation Economics and finance Carbon budget Carbon emission trading Carbon offsets and credits Gold Standard (carbon offset standard) Carbon price Carbon tax Climate debt Climate finance Climate risk insurance Co-benefits of climate change mitigation Economics of climate change mitigation Fossil fuel divestment Green Climate Fund Low-carbon economy Net zero emissions Energy Carbon capture and storage Energy transition Fossil fuel phase-out Nuclear power Renewable energy Sustainable energy Preserving and enhancing carbon sinks Blue carbon Carbon dioxide removal Carbon sequestration Direct air capture Carbon farming Climate-smart agriculture Forest management afforestation forestry for carbon sequestration REDD+ reforestation Land use, land-use change, and forestry (LULUCF and AFOLU) Nature-based solutions Other Earth Strike Fridays for Future Geoengineering Individual action on climate change Positive tipping points Sustainable architecture Sustainable transport Society and adaptation Society Business action Climate action Climate emergency declaration Climate movement School Strike for Climate Denial Ecological grief Governance Justice Litigation Politics Public opinion Women Adaptation Adaptation strategies on the German coast Adaptive capacity Disaster risk reduction Ecosystem-based adaptation Flood control Loss and damage Managed retreat Nature-based solutions Resilience Risk Vulnerability The Adaptation Fund National Adaptation Programme of Action Communication Climate Change Performance Index Climate crisis (term) Climate spiral Education Media coverage Popular culture depictions art fiction video games Warming stripes International agreements Glasgow Climate Pact Integrity Council for the Voluntary Carbon Market Taskforce on Scaling Voluntary Carbon Markets Kyoto Protocol Paris Agreement Cooperative mechanisms under Article 6 of the Paris Agreement Nationally determined contributions Sustainable Development Goal 13 United Nations Framework Convention on Climate Change International Conference on Transitioning Away from Fossil Fuels Background and theory Measurements Global surface temperature Instrumental temperature record Proxy Satellite temperature measurement Theory Albedo Carbon cycle atmospheric biologic oceanic permafrost Carbon sink Climate sensitivity Climate variability and change Cloud feedback Cloud forcing Fixed anvil temperature hypothesis Cryosphere Earth's energy budget Extreme event attribution Feedbacks Global warming potential Illustrative model of greenhouse effect on climate change Orbital forcing Radiative forcing Research and modelling Climate change scenario Climate model Coupled Model Intercomparison Project Intergovernmental Panel on Climate Change (IPCC) IPCC Sixth Assessment Report Paleoclimatology Representative Concentration Pathway Shared Socioeconomic Pathways Climate change portal Category Glossary Index

v t e Sustainability Outline Index Principles Anthropocene Environmentalism Global governance Human impact on the environment Planetary boundaries Development Consumption Anthropization Anti-consumerism Circular economy Durable good Earth Overshoot Day Ecological footprint Ethical Green consumption Micro-sustainability Over-consumption Product stewardship Simple living Social return on investment Steady-state economy Sustainability Advertising Brand Marketing myopia Sustainable Consumer behaviour Market Systemic change resistance Tragedy of the commons World population Control Demographic transition Dependency ratio List Family planning Intergenerational equity Population ageing Sustainable population Technology Appropriate Environmental technology Natural building Sustainable architecture Sustainable design Sustainable industries Sustainable packaging Biodiversity Biosecurity Biosphere Conservation biology Endangered species Holocene extinction Invasive species Energy Carbon footprint Renewable energy Sustainable energy Food Civic agriculture Climate-smart agriculture Community-supported agriculture Cultured meat Sustainable agriculture Sustainable diet Sustainable fishery Water Air well (condenser) Bioretention Bioswale Blue roof Catchwater Constructed wetland Detention basin Dew pond Footprint Hydroelectricity Hydropower Infiltration basin Irrigation tank Marine energy Micro hydro Ocean thermal energy conversion Pico hydro Rain garden Rainwater harvesting Rainwater tank Reclaimed water Retention basin Run-of-the-river hydroelectricity Scarcity Security Small hydro Sustainable drainage system Tidal power Tidal stream generator Tree box filter Water conservation Water heat recycling Water recycling shower Water-sensitive urban design Accountability Corporate environmental responsibility Corporate social responsibility Environmental accounting Environmental full-cost accounting Environmental planning Generational accounting Sustainability Accounting Measurement Metrics and indices Reporting Standards and certification Sustainable yield Economic Debt Sustainability Analysis Fiscal sustainability Applications Advertising Art Business City Cultural sustainability Climate finance Community Disinvestment Eco-capitalism Eco-cities Eco-investing Eco-socialism Ecovillage Environmental finance Green economy Construction Fashion Finance Gardening Geopark Green Development Infrastructure Marketing Green roof Greening Impact investing Landscape Livelihood Living Market Organic movement Organizations Procurement Refurbishment Socially responsible business Socially responsible marketing Sanitation Sourcing Space Sustainability organization Tourism Transport Urban drainage systems Urban infrastructure Sustainable management Environmental Fisheries Forest Humanistic capitalism Landscape Materials Natural resource Planetary Recycling Waste Agreements and conferences UN Conference on the Human Environment (Stockholm 1972) Brundtlandt Commission Report (1983) Our Common Future (1987) Earth Summit (1992) Rio Declaration on Environment and Development (1992) Agenda 21 (1992) Convention on Biological Diversity (1992) Lisbon Principles (1997) Earth Charter (2000) UN Millennium Declaration (2000) Earth Summit 2002 (Rio+10, Johannesburg) UN Conference on Sustainable Development (Rio+20, 2012) Sustainable Development Goals (2015) UNESCO MONDIACULT conferences Category Lists Science Studies Degrees

v t e Emerging technologies Fields Energy Production Airborne wind turbine Artificial photosynthesis Biofuels Carbon-neutral fuel Concentrated solar power Fusion power Home fuel cell Hydrogen economy Methanol economy Molten salt reactor Nantenna Ocean thermal energy conversion Osmotic power Photovoltaic pavement Space-based solar power Vortex engine Storage Compressed-air energy storage Flywheel energy storage Grid energy storage Lithium–air battery Lithium iron phosphate battery Molten-salt battery Metal–air electrochemical cell Nanowire battery Research in lithium-ion batteries Silicon–air battery Sodium-ion battery Solid-state battery Thermal energy storage Ultracapacitor Other Alternative fuel vehicle Battery electric vehicle Hybrid electric vehicle Smart grid Wireless power List

v t e Maize and corn Varieties Amylomaize Baby Blue Dent Field Flint Flour Genetically modified List MON 810 MON 863 Purple Quality Protein Maize Shoepeg Sweet Varieties Visayan white Waxy Lagkitan By origin Bolivia Ecuador Italy Peru Parts Cob Kernel Stover Processing Corn construction Maize milling Nixtamalization Wet-milling Popcorn maker Pathology BBCH-scale Corn allergy Corn smut Maize streak virus Production Biofuel Corn crib Cornstalk fiddle By country United States Tanzania International corn production statistics List of popcorn brands Three Sisters (agriculture) Culture Corn Palace Corn School Field of Corn (1994 sculpture) National Cornbread Festival Sweet Corn Festival Zea (film) Maize dishes Ingredients Cornmeal Masa Mielie-meal Oil Samp Starch Steep liquor Syrup Glucose syrup High-fructose Public perception High-maltose Soups, stews, and porridge Banku Binte biluhuta Bulz Cocoloși Corn chowder Corn crab soup Corn pudding Corn soup Corn stew Cou-cou Creamed corn Fufu Ginataang mais Grits Hasty pudding Kačamak Mămăligă Mămăligă în pături Mush Pashofa Polenta Pozole Sagamite Suam na mais Ugali Xarém Tamales Acaçá Tamale Binaki Guanime Hallaca Humita Nacatamal Pamonha Pasteles Breads and cakes Arepa Bollo Broa Cachapa Chipa guasu Cornbread Corn cookie Corn tortilla List of tortilla-based dishes Johnnycake Makki ki roti Pastel de choclo Piki Proja Pupusa Sloosh Sope Sopa paraguaya Spoonbread Talo Tortilla Totopo Wotou Fried dishes Battered sausage Corn chip Corn dog Corn fritter Corn nut Cornick Corn schnitzel Hushpuppy Milho frito Nachos Sorullos Tostada Tortilla chip Other foods Alivenci Binatog Conkies Corn flakes Corn on the cob Corn relish Corn sauce Gofio Hominy Huitlacoche Kenkey Kuymak Maíz con hielo Maja maíz Maque choux Mote Pinole Popcorn Succotash Beverages Atole Bourbon whiskey Cauim Champurrado Chicha Chicha de jora Chicha morada Colada morada Corn beer Corn tea Corn whiskey Mazamorra Pinolillo Pozol Tejate Tejuino Tesgüino

Authority control databases International GND National United States France BnF data Japan Czech Republic Latvia Israel Other Yale LUX

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Adapted from the Wikipedia article [Biofuel](https://en.wikipedia.org/wiki/Biofuel) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Biofuel?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.