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E85 is an abbreviation for an ethanol fuel blend of 85% denatured ethanol fuel and 15% gasoline or other hydrocarbon by volume. E85 is commonly used by flex-fuel vehicles in the United States and Europe. In the United States, government subsidies of ethanol in general and E85 in particular have encouraged a growing infrastructure for retail sale of E85, especially in corn growing states in the Midwest.
E85 allegedly has a number of advantages over conventional gasoline. One claimed advantage is a reduction in tailpipe emissions, if one disregards that E85 increases the emissions of acetaldehyde in vehicles. Another advantage is a highly effective octane rating, reducing engine heat and wear, and increasing engine performance if an engine is tuned to run on E85, or able to automatically adjust to higher octane fuel. Because the ethanol component effectively displaces fossil fuels with energy harvested from renewable sources, in theory E85 is less carbon intensive than petroleum. Additionally, there is a greater potential for localized production of ethanol in agricultural areas and using waste materials. Also, a diversification of fuel sources reduces dependence on a particular type of fuel and may increase stability of supply.
Current factory-made E85 vehicles do not deliver as much fuel economy as gasoline vehicles. Some critics of flex-fuel vehicles claim that ethanol can produce fuel economy similar to that observed in gasoline engines, but automotive manufacturers fail to do the things that are necessary to do so (see Fuel economy section.)
Corrosion debate 
There is vehement debate regarding issues with fuel systems and E85. Allegedly, due to chemical differences between E85 and gasoline, fuel systems and engines not designed or modified to use E85 suffer increased wear and may fail prematurely. However, some researchers come to the opposite conclusion (Footnote 28).
There is no disagreement that some of the environmental and social benefits of ethanol, and therefore E85, are highly dependent on raw materials used to produce the fuel. However, there is great disagreement as to ethanol's role in the pricing and availability of those raw materials.
Food vs. fuel 
Ethanol critics contend that production of ethanol from corn drives up world food prices, causing corn to be unaffordable,or even unavailable at all. Ethanol advocates counter that allegation by pointing out that over 93% of all corn grown in the U.S. is never fed to people, but is instead used as livestock feed. As livestock cannot digest starch efficiently, and dried corn is mostly starch, livestock do not digest much of the starch at all, and it is simply transformed into fecal matter,or manure,not meat, eggs,or milk. U.S.farmers grow more corn every year than people can buy; there is an annual surplus of corn in the U.S (Footnote 29).
Ethanol advocates say that corn prices have increased due to manipulation of the commodities markets and because American corn companies sell more and more U.S.-grown corn to Mexico and China, creating more competition for corn buyers, and 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 fuel to transport E85, and use biomass as a heat source for the distillation of ethanol instead of petro-products like natural gas.
Some say that ethanol produced from waste materials or fast growing non-food crops such as switchgrass 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 (Footnote 26), 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 
North America 
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E85 is increasingly common in the United States, mainly in the Midwest where corn is a major crop and is the primary source material for ethanol-fuel production. As of November 7, 2012, there are over 2,400 gas stations that offer E85 fuel, according to Growth Energy, an enterprise which facilitates the offering of E85 and a service for finding E85 stations (Footnote 29).
Prices vary by location: some prices were over 30% less than regular gasoline; in other places it is only slightly less expensive.
E85 was formerly available from the Maxol chain in Ireland, where it was made from whey, a byproduct of cheese manufacturing. The availability ended in 2011, due to a severe excise-duty hike which rendered it economically unviable.
In Finland E85 is available from 26 St1 chain locations in Alavieska, Espoo, Helsinki, Hämeenlinna, Kajaani, Kemi, Keuruu, Kokkola, Kuopio, Lahti, Luumäki, Mustasaari, Mäntsälä, Pori, Porvoo, Raisio, Tampere, Turku, Vaasa and Vantaa. The E85 sold by St1 is labeled as RE85 to indicate it is manufactured from bio-waste.
Use in flexible-fuel vehicles 
E85 ethanol is used in engines modified to accept higher concentrations of ethanol. Such flexible-fuel vehicles (FFV) are designed to run on any mixture of gasoline or ethanol with up to 85% ethanol by volume. There are a few major differences between FFVs and non-FFVs. One is the elimination of bare magnesium, aluminum, and rubber parts in the fuel system. Another is that fuel pumps must be capable of operating with electrically conductive ethanol instead of non-conducting dielectric gasoline fuel. Fuel-injection control systems have a wider range of pulse widths to inject approximately 34% more fuel. Stainless steel fuel lines, sometimes lined with plastic, and stainless-steel fuel tanks in place of terne fuel tanks are used. In some cases, FFVs use acid-neutralizing motor oil. For vehicles with fuel-tank-mounted fuel pumps, additional differences to prevent arcing, as well as flame arrestors positioned in the tank's fill pipe, are also sometimes used.
Fuel economy 
Ethanol promoters contend that automotive manufacturers currently fail to equal the fuel economy of gasoline because they fail to take advantages of characteristics which are superior in ethanol-based fuel blends. (Footnotes 19,20). They claim that some ethanol engines have already produced 22% more miles per gallon than identical gasoline engines (Footnote 19). Some critics of flex-fuel vehicles say that they fail to match gasoline fuel economy because flex-fuel vehicles are inadequate, not because E85 cannot deliver as much fuel economy.
Ethanol promoters claim that today's flex-fuel vehicles are much too inexact in measuring the ethanol content because car companies will not pay the high patent royalties demanded for fuel content sensors. They state that some flex-fuel vehicles have used wastefully high-flow fuel injectors which are not necessary and waste fuel all the time on either fuel. They state that flex-fuel systems also spray too much E85, and waste fuel in consequence. The technical term is "excessive fuel pulse width modulation". Other ethanol advocates also state that it is a mistake to base ethanol engine design on gasoline engine design, but 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 (Footnote 21).
In contrast, ethanol critics contest the benefits of E85 by focusing on the fact that E85 has 33% less energy content than "pure" gasoline (and 30% less than the E10 gasohol blend that is sold by almost all retailers in the US). Depending on the vehicle, this can result in a notable reduction in fuel economy and means that, in factory-made flex-fuel vehicles, while E85 is cheaper than gasoline per gallon, per mile it is far more expensive.
If ethanol advocates (Footnotes 19,20,21) are correct, many flex-fuel vehicles fail to equal the mileage of gasoline-only engines because they do not preheat ethanol-blend fuels, or radically advance ignition timing for those fuels, or increase engine compression for E85 fuel, not because E85 contains less energy than gasoline. fuel economy is reduced for most factory-made FFVs (flexible-fuel vehicles) by about 20 to 30% when operated on E85 (summer blend). The Environmental Protection Agency states on its website that several of the most current factory-made FFVs are still losing 25% fuel efficiency when running on E85.
For factory-made FFVs, more E85 is typically needed to do the same work as can be achieved with a lesser volume of gasoline. This difference is sometimes offset by the lower cost of the E85 fuel, depending on E85's current price discount relative to the current price of gasoline. As described earlier, the best thing for drivers to do is to record fuel usage with both fuels and calculate cost/distance for them. Only by doing that can the end-user economy of the two fuels be compared. For example, an existing pre-2003-model-year American-made FFV vehicle that normally achieves, say, 30 MPG on pure gasoline will typically achieve about 22 MPG, or slightly better, on E85 (summer blend.) When operated on E85 winter blend, which is actually E70 (70% ethanol, 30% gasoline), fuel economy will be higher than when operating on the summer blend.
To achieve any short-term operational fuel-cost savings, the price of E85 should therefore be 20% or more below the price of gasoline to equalize short term fuel costs for most older pre-2003 FFVs for both winter and summer blends of E85, which it typically is. Life-cycle costs over the life of the FFV engine are theoretically lower for E85, as ethanol is a cooler-and-cleaner burning fuel than gasoline. Provided that one takes a long-term life-cycle-operating-cost view, a continuous price discount of 20% to 25% below the cost of gasoline is probably about the break-even point in terms of vehicle life-cycle operating costs for operating most FFVs on E85 exclusively (for summer, spring/fall, and winter blends).
Fuel economy in fuel-injected non-FFVs operating on a mix of E85 and gasoline varies greatly depending on the engine and fuel mix. For a 60:40 blend of gasoline to E85 (summer blend), a typical fuel-economy reduction of around 23.7% resulted in one person's[who?] carefully executed experiment with a 1998 Chevrolet S10 pickup with a 2.2L 4-cylinder engine, relative to the fuel economy achieved on pure gasoline. Similarly, for a 50:50 blend of gasoline to E85 (summer blend), a typical fuel-economy reduction of around 25% resulted for the same vehicle. (Fuel-economy performance numbers were measured on a fixed commute of approximately 110 miles (180 km) roundtrip per day, on a predominantly freeway commute, running at a fixed speed (62 mph), with cruise control activated, air conditioning ON, at sea level, with flat terrain, traveling to/from Kennedy Space Center, FL). It is important to note, however, that if the engine had been specifically tuned for consumption of ethanol (higher compression, different fuel-air mixture, etc.) the mileage would have been much better than the results above. The aforementioned fact leads some to believe that the "FFV" engine is more of an infant technology rather than fully mature.
The amount of reduction in mileage, therefore, is highly dependent upon the particulars of the vehicle design, exact composition of the ethanol-gasoline blend, and state of engine tune (primarily fuel-air mixture and compression ratio). In order to offset this change in fuel economy there has been much legislation passed to subsidize the cost. The American Jobs Creation Act of 2004 created the Volumetric Ethanol Excise Tax Credit (VEETC) to subsidize the production costs. In 2008, the 2008 Farm Bill changed the 51-cent tax credit provided by VEETC to 45 cents. There have been other measures taken by congress to jump start ethanol production. For instance, the 2004 VEETC bill provided for a Small Ethanol Producer Tax Credit which gave tax credits to small ethanol producers. More recently the Tax Relief, Unemployment Insurance Reauthorization, and Job Creation Act of 2010 extended the tax cuts allowed by VEETC that were set to expire at the end of 2010 until the end of 2012.
So in order to save money at the pump with current flex-fuel vehicles available in the United States, the price of E85 must be much lower than gasoline. E85 was at least 20% less expensive in most areas, as recently as 2011. However as of March 2012, the difference in the retail price between E85 and gasoline is 15% or less in the vast majority of the United States.  E85 also gets less MPG, at least in flex-fuel vehicles. In one test, a Chevy Tahoe flex-fuel vehicle averaged 18 MPG [U.S. gallons] for gasoline and 13 MPG for E85, or 28% fewer MPG than gasoline. In that test, the cost of gas averaged $3.42, while the cost for E85 averaged $3.09, or 90% of the cost of gasoline. In another test, however, a fleet of Ford Tauruses averaged only about 6% fewer miles per gallon in the ethanol-based vehicles as compared to traditional, gas-powered Tauruses.
Octane and performance 
||The examples and perspective in this article may not represent a worldwide view of the subject. (December 2011)|
Alcohol fuels reach their peak torqu a bit more quickly than gasoline does, so any vehicle that receives a very basic conversion to be able to run on E85 will be very slightly faster on E85.
As more effort is put into maximizing an engine to take advantage of E85's higher "octane", engines achieve greater power advantages. One car that has higher power on ethanol is the Koenigsegg CCXR, which on ethanol is the third-most powerful production car, with 20% more hp on E85 than on gasoline. According to the manufacturer, this is due to the cooling properties of ethanol.E85 has an octane rating 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. The Renewable Fuels Foundation states in its Changes in Gasoline IV manual, "There is no requirement to post octane on an E85 dispenser. If a retailer chooses to post octane, they should be aware that the often cited 105 octane is incorrect. This number was derived by using ethanol’s blending octane value in gasoline. This is not the proper way to calculate the octane of E85. Ethanol’s true octane value should be used to calculate E85’s octane value. This results in an octane range of 94-96 (R+M)/2. These calculations have been confirmed by actual-octane engine tests." 
Examples of this mis-citation can be found at the Iowa Renewable Fuels Association titled "E85 Facts" which cites a range of 100-105, and a document at the Texas State Energy Conservation Office titled "Ethanol", which cites a 113 rating.
Use of E85 in an engine designed specifically for gasoline would result in a loss of the potential efficiency that it is possible to gain with this fuel. Use of gasoline in an engine with a high enough compression ratio to use E85 efficiently would likely result in catastrophic failure due to engine detonation, as the octane rating of gasoline is not high enough to withstand the greater compression ratios in use in an engine specifically designed to run on E85. (However, Flex Fuel Vehicles are designed to run on any mixture of gasoline and ethanol, from pure gasoline to E85, and avoid this problem.) Using E85 in a gasoline engine has the drawback of achieving lower fuel economy, as more fuel is needed per unit air (stoichiometric ratio) to run the engine in comparison with gasoline. The additional ethanol required for a stoichiometric fuel ratio helps compensate for lack of energy provided by ethanol's lower heating value (LHV), which is lower than the LHV of gasoline.
Some vehicles can actually be converted to use E85 despite not being specifically built for it. Because of 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 also resulted in 10-12% power and torque increase at the wheels. Because of its low price (less than $2.00/gal in some places) 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 $10.00/gal.
E85 consumes more fuel in flex-fuel type vehicles when the vehicle uses the same compression ratio for both E85 and gasoline, because of its lower stoichiometric fuel ratio and lower heating value. European car maker Saab, now defunct, produced a flex-fuel version of their 9-5 sedan, which consumes the same amount of fuel whether running E85 or gasoline.
When environmentalists concern themselves with emissions from combustion engines there are four primary types of pollutants scientists study. These emissions are hydrocarbons (HC), oxides of nitrogen (NOx), carbon monoxide (CO) and carbon dioxide (CO2). Because E85 is predominantly ethanol the tailpipe emissions are much different than that of regular gasoline. There have been numerous studies done to compare and contrast 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 vehicles overall fuel efficiency all play a large role in the overall outcome of each study. 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.
EPA's stringent tier-II vehicle emission standards require that FFVs achieve the same low emissions level regardless of 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 also increases emissions of acetaldehyde. EPA is conducting additional analysis to expand our understanding of the emissions impacts of E85.
See also 
- Air-fuel ratio
- Alcohol fuel
- Common ethanol fuel mixtures – common ratios other than 85%/15%.
- Earth's atmosphere
- Ethanol fuel
- Fuel injection
- lambda sensor – also known as an oxygen sensor, used to measure lean versus rich combustion conditions
- Methanol – wood alcohol, not to be confused with ethanol (grain alcohol)
- Stoichiometry – thermodynamics issues for obtaining the proper air fuel mixture for complete combustion
- Switchgrass – a hardy perennial grass that is being considered as a biofuel
- Timeline of alcohol fuel
- "Alternative Fuels and Advanced Vehicles: E85." US Department of Energy. afdc.energy.gov Retrieved March 15, 2012.
- "Maxol Bioethanol E85 leaflet" (PDF). Retrieved 2010-12-05.
- "Suomi - Hae St1/Shell-asemia". St1.fi. Retrieved 2012-12-26.
- "Suomi - RE85". St1.fi. Retrieved 2012-12-26.
- Frequently Asked Questions: How much ethanol is in gasoline and how does it affect fuel economy? era.gov Retrieved March 15, 2012
- Wiesenfelder, Joe. "Fuel Economy | Gas Alternatives". Cars.com. Retrieved 2010-12-05.
- "E85 Prices". E85 Prices. Retrieved 2010-12-05.
- "E85 vs Gasoline Comparison test". Edmunds.com. Retrieved 2010-12-05.
- "Ethanol: The facts, the questions | desmoinesregister.com". The Des Moines Register. Retrieved 2010-04-04.
- "Ohio’s First Ethanol-Fueled Light-Duty Fleet". Archived from the original on October 30, 2004.
- Changes in Gasoline IV, sponsored by Renewable Fuels Foundation
- Iowa Renewable Fuels Association "E85 Facts"
- Texas State Energy Conservation Office "Ethanol"
- Liquor Does It Quicker, Matthew Phenix, Popular Science. Retrieved April 29, 2008.
- Journal of the Air & Waste Management Association, Vol. 59 (Issue 8)
- Atmospheric Environment, Vol. 45, Issue 39
- [dead link]
19 M. Brusstar, et al., “High Efficiency and Low Emissions from a Port-Injected Engine with Neat Alcohol Fuels”, SAEPaper 2002-01-2743, 2002.
20 Alcohol Can Be a Gas Blume, David 2007 Preheating; pp. 406–410, Advancement of Ignition Timing: pp. 404, 417-18, 530 'Higher Compression with Ethanol'pp. 70, 358-60, 415-19,429, 433-435
21 US EPA/OAR/Office of Transportation & Air Quality/Advanced Technology Division and FEV Engine Technology; Inc. "Economical, High-Efficiency Engine Technologies for Alcohol Fuels "
22 ORNL/TM-2010/326 Intermediate Ethanol Blends Infrastructure Materials Compatibility Study: Elastomers, Metals, and Sealants Oak Ridge National Energy Laboratory, Prepared by M. D. Kass T. J. Theiss C. J. Janke S. J. Pawel S. A. Lewis
23 USDA predicts record corn yields, prices between $4.20 and $5 7:41 AM, May 10, 2012 | by Dan Piller Des Moines Register
Further reading 
- Handbook for Handling Storing and Dispensing E85 National Rewnewable Energy Laboratory, April 2006, US Department of Energy
- Flex-Fuel Bait and Switch - 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. ethanol Distillation: Basic Principles, Equipment, Performance Relationships, and Safety Purdue University, April 1984.
- Matthew Phenix. Liquor Does It Quicker. Popular Science, June 2005.
- Ohio E85 Fleet Test Results[dead link]
- Properties 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 Report[dead link]
- University of Michigan E85 Control of Emissions Report
- University of Nebraska-Lincoln Report on E85 Conversion of Silverado Pickup
- LiveGreen GoYellow
- Energy and Greenhouse Gas Emissions Impacts of Fuel Ethanol Argonne National Laboratory
- European Ethanol E85 conversion kits
- American Coalition of Ethanol E10 - E30 Fuel Economy Study
- U.S. DOE's Alternative Fuels Data Center - Ethanol
- EPA Presentation and Technical paper it is based upon.
- USDA Ethanol Production Cost Reduction Announcement - US Government Tax Subsidy to End in 2007
- Winning The Oil Endgame Rocky Mountain Institute's fuel strategy
- Think Outside The Barrel - Video of a talk by Vinod Khosla at Google TechTalks
- Flex-fuel Bait and Switch - 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