E85 is an abbreviation typically referring to an
ethanol fuel blend of 85%
ethanol fuel and 15%
gasoline
Gasoline ( North American English) or petrol ( Commonwealth English) is a petrochemical product characterized as a transparent, yellowish, and flammable liquid normally used as a fuel for spark-ignited internal combustion engines. When for ...
or other
hydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and Hydrophobe, hydrophobic; their odor is usually fain ...
by
volume
Volume is a measure of regions in three-dimensional space. It is often quantified numerically using SI derived units (such as the cubic metre and litre) or by various imperial or US customary units (such as the gallon, quart, cubic inch) ...
.
In the
United States
The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...
, the exact ratio of fuel ethanol to hydrocarbon may vary according to ASTM 5798 that specifies the allowable ethanol content in E85 as ranging from 51% to 83%.
[afdc.energy.gov]
''Handbook for Handling, Storing, and Dispensing E85 and Other Ethanol-Gasoline Blends.'' US Department of Energy. Retrieved October 2, 2013. This is due to the
lower heating value of
neat ethanol making it difficult to start engines in relatively cold climates without pre-heating air intake, faster cranking, or mixing varying fractions of gasoline according to climate. Cold starting in cold climates is the primary reason ethanol fuel is blended with any gasoline fraction.
In Brazil, ethanol fuel is neat at the pumps, hence
flexible-fuel vehicles (FFV) including trucks, tractors, motorbikes and mopeds run on E100. The 85% fraction is commonly sold at pumps worldwide (outside the US), and when specifically supplied or sold as E85 is always 85% ethanol (at pumps or in barrel). Having a guaranteed ethanol fraction obviates the need for a vehicle system to calculate best engine tune accordingly to maximise performance and economy.
In countries like Australia where E85 is always 85% ethanol (and pump fuel with varying fractions is called "flex fuel"), performance motoring enthusiasts and motor racing clubs/championships use E85 extensively (without the need for any FFV certification). Use of alcohol (ethanol and methanol) in motor racing history parallels the invention of the automobile, favoured due to inherent combustion characteristics such as high
thermal efficiency
In thermodynamics, the thermal efficiency (\eta_) is a dimensionless performance measure of a device that uses thermal energy, such as an internal combustion engine, steam turbine, steam engine, boiler, furnace, refrigerator, ACs etc.
For ...
, high
octane rating
An octane rating, or octane number, is a standard measure of a liquid fuel, fuel's ability to withstand Compression ratio, compression in an internal combustion engine without causing engine knocking. The higher the octane number, the more compres ...
, raised torque and with some advanced engines, better specific fuel consumption. In the United States, government
subsidies
A subsidy, subvention or government incentive is a type of government expenditure for individuals and households, as well as businesses with the aim of stabilizing the economy. It ensures that individuals and households are viable by having acce ...
of ethanol in general and E85 in particular have encouraged a growing infrastructure for the retail sale of E85, especially in
corn growing states in the
Midwest
The Midwestern United States (also referred to as the Midwest, the Heartland or the American Midwest) is one of the four census regions defined by the United States Census Bureau. It occupies the northern central part of the United States. It ...
.
Fuel economy
Specific fuel consumption
E85 promoters and the Society of Automotive Engineers contend that automotive manufacturers currently fail to equal the fuel consumption of gasoline because they fail to take advantages of characteristics which are superior in ethanol-based fuel blends. They claim that some ethanol engines have already produced 22% more miles per gallon than identical gasoline engines.
Ethanol advocates also state that it is a mistake to base ethanol engine design on gasoline engine design, and that ethanol engines should be based on diesel engine design parameters instead. Using this approach, the EPA has produced an ethanol-only engine which achieves much higher brake thermal efficiency levels than gasoline engines achieve. Mileage is dependent upon the composition of the ethanol-gasoline blend, transmission, state of engine tune (primarily
fuel-air mixture, spark timing and compression ratio). In the United States to offset this difference in fuel consumption in vehicles not optimised for ethanol, legislation has been passed to subsidize its cost.
Energy value
In contrast, ethanol critics contest the benefits of E85 by focusing on the fact that E85 has 33%
lower heating value compared to the
higher heating value
The heating value (or energy value or calorific value) of a substance, usually a fuel or food (see food energy), is the amount of heat released during the combustion of a specified amount of it.
The ''calorific value'' is the total energy release ...
of gasoline. However comparing energy expressed as a value of heat does not reflect the total work from an
Otto Cycle. As
energy content does not factor certain latent or specific heat values, nor combustion pressure, looking at heat alone in the combustion equation does not determine efficiency or work according to the
laws of thermodynamics
The laws of thermodynamics are a set of scientific laws which define a group of physical quantities, such as temperature, energy, and entropy, that characterize thermodynamic systems in thermodynamic equilibrium. The laws also use various param ...
.
Octane and performance
Use in flexible-fuel vehicles
E85 ethanol is used in engines modified to accept higher concentrations of ethanol. In the US such FFVs are designed to run on any mixture of gasoline or ethanol up to 85% ethanol, whereas in countries such as Brazil where the climate is typically warmer, FFVs run on neat alcohol. There are a few major differences between FFVs and non-FFVs. One is the elimination of bare
magnesium
Magnesium is a chemical element; it has Symbol (chemistry), symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 ...
,
aluminum
Aluminium (or aluminum in North American English) is a chemical element; it has chemical symbol, symbol Al and atomic number 13. It has a density lower than that of other common metals, about one-third that of steel. Aluminium has ...
, and
rubber
Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of polymers of the organic compound isoprene, with minor impurities of other organic compounds.
Types of polyisoprene ...
parts in the fuel system.
Fuel injection
Fuel injection is the introduction of fuel in an internal combustion engine, most commonly automotive engines, by the means of a fuel injector. This article focuses on fuel injection in reciprocating piston and Wankel rotary engines.
All c ...
control systems have a wider range of pulse widths to inject up to 34% more fuel (which in turn produces more power).
Stainless steel
Stainless steel, also known as inox, corrosion-resistant steel (CRES), or rustless steel, is an iron-based alloy that contains chromium, making it resistant to rust and corrosion. Stainless steel's resistance to corrosion comes from its chromi ...
fuel lines, sometimes lined with plastic, and stainless-steel fuel tanks in place of
terne (
tinplate
Tinplate consists of sheet metal, sheets of steel coated with a thin layer of tin to impede rust, rusting. Before the advent of cheap mild steel, the backing metal (known as "") was wrought iron. While once more widely used, the primary use of tinp ...
) fuel tanks have been used. In some cases, FFVs use specific engine oil that neutralises acidity. For vehicles with in-tank-mounted fuel pumps, precautions to prevent
arcing, as well as
flame arrestors positioned in the tank's fill pipe, are sometimes used.
Octane rating
As more effort is put into maximizing an engine to take advantage of E85's higher octane rating, engines achieve greater power advantages. One car that has higher power on ethanol is the
Koenigsegg CCXR, which on ethanol is the fifth-most powerful production car, with 20% more horsepower on E85 than on gasoline. According to the manufacturer, this is due to the cooling properties of ethanol. E85 has an
octane rating
An octane rating, or octane number, is a standard measure of a liquid fuel, fuel's ability to withstand Compression ratio, compression in an internal combustion engine without causing engine knocking. The higher the octane number, the more compres ...
higher than that of regular gasoline's typical rating of 87, or premium gasoline's 91-93. This allows it to be used in higher-compression engines, which tend to produce more power per unit of displacement than their gasoline counterparts. Examples of octane mis-citation can be found at the Iowa Renewable Fuels Association titled "E85 Facts"
[Iowa Renewable Fuels Associatio]
"E85 Facts"
which cites a range of 100-105, and a document at the Texas State Energy Conservation Office titled "Ethanol",
[Texas State Energy Conservation Offic]
which cites a 113 rating.
Some vehicles can be converted to use E85 despite not being specifically built for it. As the lower heating value E85 has a cooler intake charge—which, coupled with its high stability level from its high octane rating—has also been used as a "power adder" in turbocharged performance vehicles. These modifications have not only resulted in lower GHG emissions, but typically resulted in 10-12% power and torque increase at the wheels. Where the engine was previously knock limited by gasoline, power improvements are as high as 40%.
Due to its low price and high availability in certain areas people have started to turn to using it in place of high-end racing fuels, which typically cost over US $10.00/gal.
Emissions
There are four primary types of pollutants scientists study. These emissions are hydrocarbons (HC), oxides of nitrogen (NO
x), carbon monoxide (CO) and carbon dioxide (CO
2). As E85 is predominantly ethanol, the exhaust emissions are very different from those of regular gasoline. Numerous studies have compared and contrasted the different emissions and the effects these emissions have on the environment, but the tests have been inconclusive. The tests have shown very little consistency if any at all because there are too many variables involved. The make and model of the vehicle, the way in which the ethanol was produced and the vehicle's overall
fuel efficiency
Fuel efficiency (or fuel economy) is a form of thermal efficiency, meaning the ratio of effort to result of a process that converts chemical energy, chemical potential energy contained in a carrier (fuel) into kinetic energy or Mechanical work, w ...
all play a large role in the overall outcome of each study.
[Journal of the Air & Waste Management Association, Vol. 59 (Issue 8)] To address the problem of inaccuracy, engineers at the National Renewable Energy Laboratory combined data from all applicable emissions studies and compiled them into one data set. This compiled set of data showed that on average all emissions that are federally regulated showed a decrease or no statistically relevant difference between E85 and gasoline.
[Atmospheric Environment, Vol. 45, Issue 39]
EPA's stringent tier-II vehicle emission standards require that FFVs achieve the same low emissions level regardless whether E85 or gasoline is used. However, E85 can further reduce emissions of certain pollutants as compared to conventional gasoline or lower-volume ethanol blends. For example, E85 is less volatile than gasoline or low-volume ethanol blends, which results in fewer evaporative emissions. Using E85 also reduces carbon-monoxide emissions and provides significant reductions in emissions of many harmful toxics, including benzene, a known human carcinogen. However, E85 in certain engine operating conditions may increase emissions of
acetaldehyde
Acetaldehyde (IUPAC systematic name ethanal) is an organic compound, organic chemical compound with the chemical formula, formula , sometimes abbreviated as . It is a colorless liquid or gas, boiling near room temperature. It is one of the most ...
. EPA is conducting additional analysis to expand our understanding of the emissions impacts of E85.
Controversy
Economics
A study by
Purdue University
Purdue University is a Public university#United States, public Land-grant university, land-grant research university in West Lafayette, Indiana, United States, and the flagship campus of the Purdue University system. The university was founded ...
found that the economic benefit of E85 is highly dependent on the price of
crude oil
Petroleum, also known as crude oil or simply oil, is a naturally occurring, yellowish-black liquid chemical mixture found in geological formations, consisting mainly of hydrocarbons. The term ''petroleum'' refers both to naturally occurring u ...
.
Food vs. fuel
E85 critics contend that production of ethanol from corn (maize) drives up
world food prices, causing corn to be unaffordable or even unavailable. E85 advocates counter that concern by pointing out that over 93% of all
corn grown in the United States is never fed directly to people, but is instead used as
livestock feed
Fodder (), also called provender (), is any agriculture, agricultural foodstuff used specifically to feed domesticated livestock, such as cattle, domestic rabbit, rabbits, sheep, horses, chickens and pigs. "Fodder" refers particularly to food ...
. Corn used to produce ethanol contains a high amount of starch and is not easily digestible by humans, like
sweet corn
Sweet corn (''Zea mays'' convar. ''saccharata'' var. ''rugosa''), also called sweetcorn, sugar corn and pole corn, is a variety of maize grown for human consumption with a high sugar content. Sweet corn is the result of a naturally occurring rec ...
. American farmers grow more corn than people purchase; there is an annual surplus of corn in the U.S.
E85 advocates say that corn prices have increased due to manipulation of the
commodities markets and because American corn companies sell more and more US-grown corn to
Mexico
Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...
and
China
China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...
, creating more competition for corn buyers, and therefore driving up its price. E85 critics contend that ethanol producers may not reduce
carbon emissions due to the petroleum and natural gas used in raising corn and refining it. E85 advocates reply by pointing to ethanol producers who do not do so, but instead use E85 or
biodiesel
Biodiesel is a renewable biofuel, a form of diesel fuel, derived from biological sources like vegetable oils, animal fats, or recycled greases, and consisting of long-chain fatty acid esters. It is typically made from fats.
The roots of bi ...
fuel to transport E85, and use
biomass
Biomass is a term used in several contexts: in the context of ecology it means living organisms, and in the context of bioenergy it means matter from recently living (but now dead) organisms. In the latter context, there are variations in how ...
as a heat source for the
distillation
Distillation, also classical distillation, is the process of separating the component substances of a liquid mixture of two or more chemically discrete substances; the separation process is realized by way of the selective boiling of the mixt ...
of ethanol instead of petro-products like natural gas.
Some say that
cellulosic ethanol
Cellulosic ethanol is ethanol (ethyl alcohol) produced from cellulose (the stringy fiber of a plant) rather than from the plant's seeds or fruit. It can be produced from grasses, wood, algae, or other plants. It is generally discussed for use as a ...
produced from waste materials or fast growing non-food crops such as
switchgrass
''Panicum virgatum'', commonly known as switchgrass, is a perennial warm season bunchgrass native to North America, where it occurs naturally from 55th parallel north, 55°N latitude in Canada southwards into the United States and Mexico. Switch ...
is much more beneficial, but not yet economically practical at large scale. Others say that the world can easily replace all of its use of petroleum by simply making ethanol from the many crops that yield more ethanol per acre than corn yields, with existing technology, not future technology, and that certain elements in the cellulosic ethanol field are more interested in patent rights than in producing the greatest amount of ethanol at the lowest price point.
Availability and price

E85 is increasingly common in the
United States
The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...
, mainly in the
Midwest
The Midwestern United States (also referred to as the Midwest, the Heartland or the American Midwest) is one of the four census regions defined by the United States Census Bureau. It occupies the northern central part of the United States. It ...
where corn is a major
crop
A crop is a plant that can be grown and harvested extensively for profit or subsistence. In other words, a crop is a plant or plant product that is grown for a specific purpose such as food, Fiber, fibre, or fuel.
When plants of the same spe ...
and is the primary source material for ethanol-fuel production. As of July 1, 2014, there were more than 3,300 fuel stations that offered E85 fuel. E85 as a
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 (physics), work. The concept was originally applied solely to those materials capable of releasing chem ...
is widely used in
Sweden
Sweden, formally the Kingdom of Sweden, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. It borders Norway to the west and north, and Finland to the east. At , Sweden is the largest Nordic count ...
; however, most of it is imported from Italy and Brazil. E85 was formerly available from the
Maxol chain in
Ireland
Ireland (, ; ; Ulster Scots dialect, Ulster-Scots: ) is an island in the North Atlantic Ocean, in Northwestern Europe. Geopolitically, the island is divided between the Republic of Ireland (officially Names of the Irish state, named Irelan ...
, where it was made from
whey
Whey is the liquid remaining after milk has been curdled and strained. It is a byproduct of the manufacturing of cheese or casein and has several commercial uses. Sweet whey is a byproduct resulting from the manufacture of rennet types of hard c ...
, a byproduct of
cheese
Cheese is a type of dairy product produced in a range of flavors, textures, and forms by coagulation of the milk protein casein. It comprises proteins and fat from milk (usually the milk of cows, buffalo, goats or sheep). During prod ...
manufacturing.
The availability ended in 2011, due to a severe excise-duty hike which rendered it economically unviable. In
Finland
Finland, officially the Republic of Finland, is a Nordic country in Northern Europe. It borders Sweden to the northwest, Norway to the north, and Russia to the east, with the Gulf of Bothnia to the west and the Gulf of Finland to the south, ...
E85 is available from 52 St1 chain locations and 71 ABC chain locations.
The E85 sold by St1 is labeled as RE85 and as "Eko E85" in ABC-stations to indicate it is manufactured from Finnish bio-waste.
By way of international price comparison, in the Cook Islands as with many of the Pacific Islands, cost of producing 100% ethanol from coconut biomass is a fraction of obtaining
fossil fuels
A fossil fuel is a flammable carbon compound- or hydrocarbon-containing material formed naturally in the Earth's crust from the buried remains of prehistoric organisms (animals, plants or microplanktons), a process that occurs within geologica ...
. In France, about 30% of gas stations supply E85, or about 2,725 stations, and the number of flex-fuel kits installed doubled in 2021 to 30,000 kits from the previous year. E85 was launched in the
United Kingdom
The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Northwestern Europe, off the coast of European mainland, the continental mainland. It comprises England, Scotlan ...
on March 14 2006 by the
Morrisons
Wm Morrison Supermarkets Limited, trading as Morrisons, is the List of supermarket chains in the United Kingdom, fifth largest supermarket chain in the United Kingdom. As of 2021, the company had 497 supermarkets across England, Wales and Sco ...
supermarket chain. The Morrisons branch in
Norwich
Norwich () is a cathedral city and district of the county of Norfolk, England, of which it is the county town. It lies by the River Wensum, about north-east of London, north of Ipswich and east of Peterborough. The population of the Norwich ...
was the first forecourt to introduce E85.
Take-up however was very low and E85 is now only available at a small number of outlets.
US price regulation
The American Jobs Creation Act of 2004 created the Volumetric Ethanol Excise Tax Credit (VEETC) to subsidize production costs. The 2008 Farm Bill reduced the VEETC's 51-cent tax credit to 45 cents. Other measures taken by Congress to jump start ethanol production include the 2004 VEETC bill, which provided for a Small Ethanol Producer Tax Credit which gave tax credits to small ethanol producers. More recently, the Tax Relief Act, Unemployment Insurance Reauthorization Act, and Job Creation Act of 2010 extended the tax cuts allowed by VEETC from the end of 2010 to the end of 2012.
In the United States, to realize equivalent fuel economy at the pump with an FFV, the price of E85 must be much lower than gasoline. E85 was at least 20% less expensive in most areas as recently as 2011. In one US test, a 2007 Chevy Tahoe FFV averaged 18.3 MPG (U.S. gallons) for gasoline and 13.5 MPG for E85, 26.5% worse than gasoline. However, in Australia, where Holden has sold more than 70,000 FFVs since 2010, the difference in combined consumption on similar V8 variants in a family sedan is between 10% and 20%. In 2010, the cost of fuel in the US averaged US$3.42, while the cost for E85 averaged US$3.09, or 90% of the cost of gasoline.
In another test, however, a fleet of
Ford Taurus
The Ford Taurus is an automobile that was manufactured and marketed by the Ford Motor Company in the United States from 1985 to 2019. From 1985 to 2009, Ford marketed the Taurus alongside its rebadged variant, the Mercury Sable. Four generati ...
es averaged only about 6% fewer miles per gallon in ethanol-based vehicles when compared to traditional, gas-powered Tauruses.
See also
*
Alcohol fuel
Various alcohols are used as fuel for internal combustion engines. The first four aliphatic alcohols (methanol, ethanol, propanol, and butanol) are of interest as fuels because they can be synthesized chemically or biologically, and they have ...
*
Earth's atmosphere
The atmosphere of Earth is composed of a layer of gas mixture that surrounds the Earth's planetary surface (both lands and oceans), known collectively as air, with variable quantities of suspended aerosols and particulates (which create weathe ...
*
Lambda sensor – also known as an oxygen sensor, used to measure lean versus rich combustion conditions
*
Methanol
Methanol (also called methyl alcohol and wood spirit, amongst other names) is an organic chemical compound and the simplest aliphatic Alcohol (chemistry), alcohol, with the chemical formula (a methyl group linked to a hydroxyl group, often ab ...
– wood alcohol, not to be confused with ethanol (grain alcohol)
*
Timeline of alcohol fuel
References
Further reading
Handbook for Handling, Storing, and Dispensing E85 and Other Ethanol-Gasoline BlendsSeptember 2013, US Department of Energy
- See how many flex-fuel cars are on the road and how many stations offer E85. Center for American Progress
*Eric Kvaalen, Philip C. Wankat, Bruce A. McKenzie
Purdue University, April 1984.
*Matthew Phenix
''
Popular Science
Popular science (also called pop-science or popsci) is an interpretation of science intended for a general audience. While science journalism focuses on recent scientific developments, popular science is more broad ranging. It may be written ...
'', June 2005.
Ohio E85 Fleet Test ResultsProperties of ethanol Transportation Fuels- USDOE Report,
Alcohol Fuels Reference Work #1, July 1991 (Especially Chapter 7 for corrosion and increased engine wear risks associated with water-contaminated E85)
University of Michigan E85 Emissions ReportUniversity of Michigan E85 Control of Emissions ReportUniversity of Nebraska-Lincoln Report on E85 Conversion of Silverado PickupLiveGreen GoYellowEnergy and Greenhouse Gas Emissions Impacts of Fuel Ethanol Argonne National Laboratory
External links
French manufacturer of Ethanol E85 conversion kitsAmerican Coalition of Ethanol E10 - E30 Fuel Economy StudyEPA Presentationan
Technical paperit is based upon.
- US Government Tax Subsidy to End in 2007
Winning The Oil EndgameRocky Mountain Institute's fuel strategy
Think Outside The Barrel - Video of a talk by Vinod Khosla at Google TechTalks
- See how many flex-fuel cars are on the road and how many fuel stations offer E85.
US biofuel production should be suspended, UN says
{{Automobile configuration
Ethanol fuel
Petroleum products