Common ethanol fuel mixtures

Several common ethanol fuel mixtures are in use around the world. The use of pure hydrous or anhydrous ethanol in internal combustion engines 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 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.
Ethanol fuel mixtures have "E" numbers which describe the percentage of ethanol fuel in the mixture by volume, for example, E85 is 85% anhydrous ethanol and 15% gasoline. Low-ethanol blends are typically from E5 to E25, although internationally the most common use of the term refers to the E10 blend.
Blends of E10 or less are used in more than 20 countries around the world, led by the United States, where ethanol represented 10% of the U.S. gasoline fuel supply in 2011. Blends from E20 to E25 have been used in Brazil since the late 1970s. E85 is commonly used in the U.S. and Europe for flexible-fuel vehicles. Hydrous ethanol or E100 is used in Brazilian neat ethanol vehicles and flex-fuel light vehicles and hydrous E15 called hE15 for modern petrol cars in the Netherlands.

E10 or less

E10, a fuel mixture of 10% anhydrous ethanol and 90% gasoline sometimes called gasohol, can be used in the internal combustion engines of most modern automobiles and light-duty vehicles without need for any modification on the engine or fuel system. E10 blends are typically rated as being 2 to 3 octane numbers higher than regular gasoline and are approved for use in all new U.S. automobiles, and mandated in some areas for emissions and other reasons.
Other common blends include E5 and E7. These concentrations are generally safe for recent engines that should run on pure gasoline. As of 2006, mandates for blending bioethanol into vehicle fuels had been enacted in at least 36 states/provinces and 17 countries at the national level, with most mandates requiring a blend of 10 to 15% ethanol with gasoline.
One measure of alternative fuels in the U.S. is the "gasoline-equivalent gallon". In 2002, the U.S. used as motor fuel, ethanol equal to, the energy equivalent of of gasoline. This was less than 1% of the total fuel used that year.
E10 and other blends of ethanol are considered to be useful in decreasing U.S. dependence on foreign oil, and can reduce carbon monoxide emissions by 20 to 30% under the right conditions. Although E10 does decrease emissions of CO and greenhouse gases such as CO₂ by an estimated 2% over regular gasoline, it can cause increases in evaporative emissions and some pollutants depending on factors such as the age of the vehicle and weather conditions. According to the Philippine Department of Energy, the use of up to 10% ethanol-gasoline mixture is not harmful to cars' fuel systems. Generally, automobile gasoline containing alcohol is not recommended to be used in aircraft.

Availability

E10 became the standard fuel at petrol stations in the United Kingdom as of September 2021.
E10 was introduced nationwide in Thailand in 2007, and replaced 91 octane pure gasoline in that country in 2013.
E10 is commonly available in the Midwestern United States. It was also mandated for use in all standard automobile fuel in the state of Florida by the end of 2010. Due to the phasing out of MTBE as a gasoline additive and mainly due to the mandates established in the Energy Policy Act of 2005 and the Energy Independence and Security Act of 2007, ethanol blends have increased throughout the United States, and by 2009, the ethanol market share in the U.S. gasoline supply reached almost 8% by volume.
Mandatory blending of ethanol was approved in Mozambique, but the percentage in the blend has not been specified.
South Africa approved a biofuel strategy in 2007, and mandated an 8% blend of ethanol by 2013.
A 2007 Uruguayan law mandates a minimum of 5% of ethanol blended with gasoline starting in January 2015. The monopolic, state-owned fuel producer ANCAP started blending premium gasoline with 10% of bioethanol in December 2009, which will be available in all the country by early January 2010.
The Dominican Republic has a mandate for blending 15% of ethanol by 2015.
Chile is considering the introduction of E5, and Panama, Bolivia and Venezuela of E10.
India achieved the target of 10 percent ethanol blending, 5 months ahead of schedule, in June 2022.
From January 2018, all 92-octane fuel in Vietnam is mandated to contain 5 percent ethanol. No ethanol blending is required for 95-octane fuel.
From June 2021, Argentina approved an E12 minimum, and after October 2022 a waiver for a maximum of E15.

A 2011 study conducted by VTT Technical Research Centre of Finland found practically no difference in fuel consumption in normal driving conditions between commercial gasoline grades 95E10 and 98E5 sold in Finland, despite the public perception that fuel consumption is significantly higher with 95E10. VTT performed the comparison test under controlled laboratory conditions and their measurements showed that over a distance of, the cars tested used an average of of 95E10, as opposed to of 98E5. The difference was 0.07 in favor of 98E5 on average, meaning that using 95E10 gasoline, which has a higher ethanol content, increases consumption by 0.7%. When the measurements are normalized, the difference becomes 1.0%, a result that is highly consistent with an estimation of calorific values based on approximate fuel composition, which came out at 1.1% in favour of E5.

Sweden

In Sweden, all 95-octane gasoline is E10 since 1 August 2021, when the proportion of ethanol was increased from E5. In the early-mid-1990s, some fuel chains also sold E10. All newer and many older petrol cars bought in Sweden should handle this, since from January 2011, the Fuel Quality Directive applied through its transposition into the law of Sweden as a member of the 27 member states of the EU.

E15

E15 contains 15% ethanol and 85% gasoline. This is generally the highest ratio of ethanol to gasoline that is possible to use in vehicles recommended by some auto manufacturers to run on E10 in the US. This is due to ethanol's hydrophilia and solvent power.
As a result of the Energy Independence and Security Act of 2007, which mandates an increase in renewable fuels for the transport sector, the U.S. Department of Energy began assessments for the feasibility of using intermediate ethanol blends in the existing vehicle fleet as a way to allow higher consumption of ethanol fuel. The National Renewable Energy Laboratory conducted tests to evaluate the potential impacts of intermediate ethanol blends on legacy vehicles and other engines. In a preliminary report released in October 2008, the NREL presented the results of the first evaluations of the effects of E10, E15 and E20 gasoline blends on tailpipe and evaporative emissions, catalyst and engine durability, vehicle driveability, engine operability, and vehicle and engine materials. This preliminary report found none of the vehicles displayed a malfunction indicator light as a result of the ethanol blend used; no fuel filter plugging symptoms were observed; no cold start problems were observed at and laboratory conditions; and as expected, computer technology available in newer model vehicles adapts to the higher octane causing lower emissions with greater horsepower and in some cases greater fuel economy.
Other sources make the opposite claim about fuel economy. According to Consumer Reports, "ethanol isn’t as energy-dense as regular gasoline so you will see worse fuel economy with E15 gas.”
In March 2009, a lobbying group from the ethanol industry, Growth Energy, formally requested the U.S. Environmental Protection Agency to allow the ethanol content in gasoline to be increased from 10% to 15%. Organizations doing such studies included the Energy Department, the State of Minnesota, the Renewable Fuels Association, the Rochester Institute of Technology, the Minnesota Center for Automotive Research, and Stockholm University in Sweden.
In October 2010, the EPA granted a waiver to allow up to 15% of ethanol blended with gasoline to be sold only for cars and light pickup trucks with a model year of 2007 or later, representing about 15% of vehicles on U.S. roads. In January 2011, the waiver was expanded to authorize use of E15 to include model year 2001 through 2006 passenger vehicles. The EPA also decided not to grant any waiver for E15 use in any motorcycles, heavy-duty vehicles, or nonroad engines because current testing data do not support such a waiver. According to the Renewable Fuels Association, the E15 waivers now cover 62% of vehicles on the road in the US, and the ethanol group estimates if all 2001 and newer cars and pickups were to use E15, the theoretical blend wall for ethanol use would be approximately 17.5 billion gallons per year. The EPA was still studying if older cars can withstand a 15% ethanol blend.
The EPA waiver authorizes sale of E15 only from Sep 15 to May 31 out of a black hose and a yellow hose to flex fuel vehicles only from June 1 to Sep 14. Retailers have shunned building infrastructure due to the costly regulatory requirements which have created a practical barrier to the commercialization of the higher blend. Most fuel stations do not have enough pumps to offer the new blend, few existing pumps are certified to dispense E15, and no dedicated tanks are readily available to store E15. Also, some state and federal regulations would have to change before E15 can be legally sold. The National Association of Convenience Stores, which represents most gasoline retailers, considers the potential for actual E15 demand is small, "because the auto industry is not embracing the fuel and is not adjusting their warranties or recommendations for the fuel type." One possible solution to the infrastructure barriers is the introduction of blender pumps that allow consumers to turn a dial to select the level of ethanol, which would also allow owners of flexible-fuel cars to buy E85 fuel.
In June 2011 EPA, in cooperation with the Federal Trade Commission, issued its final ruling regarding the E15 warning label required to be displayed in all E15 fuel dispensers in the U.S. to inform consumers about what vehicles can, and what vehicles and equipment cannot, use the E15 blend. Both the Alliance of Automobile Manufacturers and the National Petrochemical and Refiners Association complained that relying solely on this warning label is not enough to protect consumers from misfueling. In July 2012, a fueling station in Lawrence, Kansas became the first in the U.S. to sell the E15 blend. The fuel is sold through a blender pump that allows customers to choose between E10, E15, E30 or E85, with the latter blends sold only to flexible-fuel vehicles., there are about 24 fueling stations selling E15 out of 180,000 stations across the U.S.
In December 2010, several groups, including the Alliance of Automobile Manufacturers, the American Petroleum Institute, the Association of International Automobile Manufacturers, the National Marine Manufacturers Association, the Outdoor Power Equipment Institute, and the Grocery Manufacturers Association, filed suit against the EPA in the United States Court of Appeals for the District of Columbia Circuit. The plaintiffs argued the EPA does not have the authority to issue a “partial waiver” that covers some cars and not others. Among other arguments, the groups argued that the higher ethanol blend is not only a problem for cars, but also for fuel pumps and underground tanks not designed for the E15 mixture. It was also argued that the rise in ethanol has contributed to the big jump in corn prices in recent years. In August 2012, the federal appeals court rejected the suit against the EPA. The case was thrown out on a technical reason, as the court ruled the groups did not have legal standing to challenge EPA's decision to issue the waiver for E15. In June 2013 the U.S. Supreme Court declined to hear an appeal from industry groups opposed to the EPA ruling about E15, and let the 2012 federal appeals court ruling stand.
, sales of E15 are not authorized in California, and according to the California Air Resources Board, the blend is still awaiting approval, and in a public statement the agency said that "it would take several years to complete the vehicle testing and rule development necessary to introduce a new transportation fuel into California's market."
According to a survey conducted by the American Automobile Association in 2012, only about 12 million out of the more than 240 million light-duty vehicles on the U.S. roads in 2012 are approved by manufacturers are fully compliant with E15 gasoline. According with the association, BMW, Chrysler, Nissan, Toyota, and Volkswagen warned that their warranties will not cover E15-related damage. Despite the controversy, in order to adjust to EPA regulations, 2012 and 2013 model year vehicles manufactured by General Motors can use fuel containing up to 15 percent ethanol, as indicated in the vehicle owners' manuals. However, the carmaker warned that for model year 2011 or earlier vehicles, they "strongly recommend that GM customers refer to their owners manuals for the proper fuel designation for their vehicles." Ford Motor Company also is manufacturing all of its 2013 vehicles E15 compatible, including hybrid electrics and vehicles with Ecoboost engines. Also Porsches built since 2001 are approved by its manufacturer to use E15. Volkswagen announced that for the 2014 model year, its entire lineup will be E15 capable. Fiat Chrysler Automobiles announced in August 2015 that all 2016 model year Chrysler/Fiat, Jeep, Dodge and Ram vehicles will be E15 compatible.
In November 2013, the Environmental Protection Agency opened for public comment its proposal to reduce the amount of ethanol required in the U.S. gasoline supply as mandated by the Energy Independence and Security Act of 2007. The agency cited problems with increasing the blend of ethanol above 10%. This limit, known as the "blend wall," refers to the practical difficulty in incorporating increasing amounts of ethanol into the transportation fuel supply at volumes exceeding those achieved by the sale of nearly all gasoline as E10.