Ethanol, an alcohol fuel, is an important fuel for the operation of internal combustion engines that are used in cars, trucks, and other kinds of machinery.
Gasoline or petrol is a transparent, slight yellowish 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.
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. Biofuels are regarded as a renewable energy source.
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 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.
Liquid fuels are combustible or energy-generating molecules that can be harnessed to create mechanical energy, usually producing kinetic energy; they also must take the shape of their container. It is the fumes of liquid fuels that are flammable instead of the fluid. Most liquid fuels in widespread use are derived from fossil fuels; however, there are several types, such as hydrogen fuel, ethanol, and biodiesel, which are also categorized as a liquid fuel. Many liquid fuels play a primary role in transportation and the economy.
Methanol fuel is an alternative biofuel for internal combustion and other engines, either in combination with gasoline or independently. Methanol (CH3OH) is less expensive to produce sustainably than ethanol fuel, although it produces more toxic effects than ethanol and has lower energy density than gasoline. Methanol is safer for the environment than gasoline, it is an anti-freeze, it keeps the engine clean, it has a higher flashpoint in case of fire, and it is the equivalent of super high-octane gasoline in terms of the resulting horsepower. To prevent vapor lock in any possible circumstances due to being a simple, pure fuel, a small percentage of other fuel or certain additives can be included. Methanol (a methyl group linked to a hydroxyl group) may be made from hydrocarbon or renewable resources, in particular natural gas and biomass respectively. It can also be synthesized from CO2 (carbon dioxide) and hydrogen. Methanol fuel is currently used by racing cars in many countries but has not seen widespread use otherwise.
E85 is an abbreviation typically referring to an ethanol fuel blend of 85% ethanol fuel and 15% gasoline or other hydrocarbon by volume.
A flexible-fuel vehicle (FFV) or dual-fuel vehicle is an alternative fuel vehicle with an internal combustion engine designed to run on more than one fuel, usually gasoline blended with either ethanol or methanol fuel, and both fuels are stored in the same common tank. Modern flex-fuel engines are capable of burning any proportion of the resulting blend in the combustion chamber as fuel injection and spark timing are adjusted automatically according to the actual blend detected by a fuel composition sensor. This device is known as an oxygen sensor and it reads the oxygen levels in the stream of exhaust gasses, its signal enriching or leaning the fuel mixture going into the engine. Flex-fuel vehicles are distinguished from bi-fuel vehicles, where two fuels are stored in separate tanks and the engine runs on one fuel at a time, for example, compressed natural gas (CNG), liquefied petroleum gas (LPG), or hydrogen.
Several common ethanol fuel mixtures are in use around the world. The use of pure hydrous or anhydrous ethanol in internal combustion engines (ICEs) is only possible if the engines are designed or modified for that purpose, and used only in automobiles, light-duty trucks and motorcycles. Anhydrous ethanol can be blended with gasoline (petrol) for use in gasoline engines, but with high ethanol content only after engine modifications to meter increased fuel volume since pure ethanol contains only 2/3 of the BTUs of an equivalent volume of pure gasoline. High percentage ethanol mixtures are used in some racing engine applications as the very high octane rating of ethanol is compatible with very high compression ratios.
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.
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.
The United States became the world's largest producer of ethanol fuel in 2005. The U.S. produced 15.8 billion U.S. liquid gallons of ethanol fuel in 2019, and 13.9 billion U.S. liquid gallons in 2011, an increase from 13.2 billion U.S. liquid gallons in 2010, and up from 1.63 billion gallons in 2000. Brazil and U.S. production accounted for 87.1% of global production in 2011. In the U.S, ethanol fuel is mainly used as an oxygenate in gasoline in the form of low-level blends up to 10 percent, and, increasingly, as E85 fuel for flex-fuel vehicles. The U.S. government subsidizes ethanol production.
The United States produces mainly biodiesel and ethanol fuel, which uses corn as the main feedstock. The US is the world's largest producer of ethanol, having produced nearly 16 billion gallons in 2017 alone. The United States, together with Brazil accounted for 85 percent of all ethanol production, with total world production of 27.05 billion gallons. Biodiesel is commercially available in most oilseed-producing states. As of 2005, it was somewhat more expensive than fossil diesel, though it is still commonly produced in relatively small quantities.
An alternative fuel vehicle is a motor vehicle that runs on alternative fuel rather than traditional petroleum fuels. The term also refers to any technology powering an engine that does not solely involve petroleum. Because of a combination of factors, such as environmental concerns, high oil-prices and the potential for peak oil, development of cleaner alternative fuels and advanced power systems for vehicles has become a high priority for many governments and vehicle manufacturers around the world.
The Renewable Fuel Standard(RFS) is an American federal program that requires transportation fuel sold in the United States to contain a minimum volume of renewable fuels. It originated with the Energy Policy Act of 2005 and was expanded and extended by the Energy Independence and Security Act of 2007. Research published by the Government Accountability Office in November 2016 found the program unlikely to meet its goal of reducing greenhouse gas emissions due to limited current and expected future production of advanced 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.
The use of biofuels varies by region. The world leaders in biofuel development and use are Brazil, United States, France, Sweden and Germany.
The history of ethanol fuel in Brazil dates from the 1970s and relates to Brazil's sugarcane-based ethanol fuel program, which allowed the country to become the world's second largest producer of ethanol, and the world's largest exporter. Several important political and technological developments led Brazil to become the world leader in the sustainable use of bioethanol, and a policy model for other developing countries in the tropical zone of Latin America, the Caribbean, and Africa. Government policies and technological advances also allowed the country to achieve a landmark in ethanol consumption, when ethanol retail sales surpassed 50% market share of the gasoline-powered vehicle fleet in early 2008. This level of ethanol fuel consumption had only been reached in Brazil once before, at the peak of the Pró-Álcool Program near the end of the 1980s.
United States policy in regard to biofuels, such as ethanol fuel and biodiesel, began in the early 1990s as the government began looking more intensely at biofuels as a way to reduce dependence on foreign oil and increase the nation's overall sustainability. Since then, biofuel policies have been refined, focused on getting the most efficient fuels commercially available, creating fuels that can compete with petroleum-based fuels, and ensuring that the agricultural industry can support and sustain the use of biofuels.
The world's top ethanol fuel producers in 2011 were the United States with 13.9 billion U.S. liquid gallons (bg) and Brazil with 5.6 bg, accounting together for 87.1% of world production of 22.36 billion US gallons. Strong incentives, coupled with other industry development initiatives, are giving rise to fledgling ethanol industries in countries such as Germany, Spain, France, Sweden, India, China, Thailand, Canada, Colombia, Australia, and some Central American countries.