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by Larry Carley copyright 2019 AA1Car.com

E15 is a blend of 15 percent ethanol alcohol and 85 percent gasoline. It is approved in the U.S. for use in ALL 2001 and newer passenger cars and light trucks, and in any Flex-Fuel vehicle.

Until this new ruling, the maximum amount of ethanol allowed in ordinary pump gasoline was 10 percent. Under the new EPA rules, gasoline refiners and retailers are allowed to sell gasoline that contains up to 15 percent ethanol for use in 2001 and newer passenger cars and light trucks. Blends that contain up to 85 percent ethanol (E85) are also allowed, but ONLY for use in FLEX-FUEL vehicles, not ordinary vehicles.

The new E15 motor fuel contains 50 per more ethanol than current gasoline (15 percent versus 10 percent). Ten percent ethanol is commonly used in reformulated gasoline, which is required in many large metropolitan areas to reduce air pollution. Ten percent ethanol (E10) is also commonly used in many premium grade 91 to 93 octane fuels as an octane booster. This improves the detonation resistance of the fuel and allows the use of higher compression ratios for better performance and fuel economy. NASCAR has been using E15 since 2012 in its race cars. With E15, the extra ethanol boosts the pump octane rating of the fuel several additional points compared to 10 percent ethanol gasoline. The pump octane rating may be as high as 98 with E15 if it is blended with a high grade gasoline, or as low as 91 to 93 octane if it is blended with a low grade gasoline. The actual pump octane rating will be determined by the refiners who supply the product.

Why Use E15?

Increasing the amount of ethanol in gasoline helps reduce the need for imported oil to make gasoline. Less demand for crude oil helps to counter the rising price of crude oil overall. Using more ethanol also helps support corn prices, which helps American farmers.

Ethanol burns cleaner than gasoline so it helps to reduce carbon deposits on pistons and inside combustion chambers. Using E15 keeps engines cleaner and running better.

How Does E15 Affect Fuel Mileage and Fuel Costs?

The higher octane rating of E15 raises detonation resistance for a slight gain in performance in high compression engines. However, ethanol contains less energy per gallon than gasoline (76,100 vs 114,100 BTUs). The energy content of E15 is about 108,400 BTUs per gallon, so it takes more fuel to produce the same amount of energy. Consequently, you can expect to get about 1.5 to 2 percent FEWER miles per gallon with E15 compared to an E10 ethanol/gasoline blend.

As for cost, there should be no significant advantage or disadvantage. E15 should be priced somewhat less than E10 or straight gasoline due to the increased ethanol content. This essentially offsets the slight difference in fuel economy between the various grades of fuel.

As we all know, fuel costs can vary greatly from one day to the next (sometimes hourly!), and from one service station to the next. The price of gasoline and corn can also change abruptly and can be affected by politics, weather and supply and demand. So the pump price of E10, E15 and straight gasoline can vary quite a bit depending on how the oil companies, fuel distributors and service stations set their prices. Oil companies often mix ethanol with lower octane gasoline to raise the overall octane rating of the fuel. This gives the oil company a better profit margin per gallon but the trade-off may be a fuel that does not delivery quite as good a mileage.

Will E15 Harm Older Vehicles?

E15 is not without controversy. Some groups oppose the use of E15 because the extra concentration of ethanol may damage some rubber and plastic fuel system components in older vehicles. The risk is primarily for vehicles built prior to 1995. Since 1995, all fuel systems have been required to be made with alcohol-resistant materials. On 2001 and newer vehicles, the fuel systems are even more alcohol resistant and should experience no problems whatsoever.

One group who opposes the introduction of E15 is SEMA (Specialty Equipment Market Assn.). SEMA has joined with a number of other trade associations to sponsor Smarter Fuel Future a website intended to raise awareness about the economic and environmental threats posed by the current U.S. biofuels policy. SEMA and the other involved organizations are calling on lawmakers to change the Renewable Fuel Standard which is calling for greater use of ethanol in gasoline. SEMA says it is concerned that the EPA may soon approve the sale of E20 (20 percent ethanol) and E30 (30 percent ethanol) fuel blends for widespread use.

Congress established the Renewable Fuel Standards (RFS) in 2005 and then set ambitious goals in 2007 to mandate biofuel sales. While SEMA supports the Congressional intent to help reduce foreign oil imports, the association says the mandates are excessive and are not supported by marketplace economics. The RFS rules led to the adoption of the new E15 fuel for use in 2001 and newer vehicles. The main concern is what happens if E15 is accidentally used in older vehicles? Many SEMA members are owners of classic muscle cars, sports cars, hot rods and other antique vehicles that have carburetors and fuel systems which were not originally designed to handle alcohol/gasoline blends.

The EPA does require service stations to post a warning label (see the E15 warning label at the top of this article) to warn consumers NOT to use E15 in vehicles made before 2001, or in motorcycles or small engines (lawnmowers, snowmobiles, etc.). The EPA says it is illegal to fuel the non-approved vehicles with E15 (so who gets in trouble if somebody breaks the law?). The EPA does require oil companies to have some means of mitigation in place to deal with problems or damages caused by misfueling. We are not quite sure what this means other than to say you have legal recourse if your fuel system suffers damage due to the use of E15.

Those who oppose the use of E15 say ethanol attracts moisture, and that may increase the risk of corrosive acids forming inside the fuel system. On the other hand, because ethanol attracts moisture, it also helps dry the fuel system to prevent gas line freeze during cold weather and other moisture-related problems. It also burns cleaner than gasoline to reduce carbon deposits in the combustion chamber and on pistons.

Will E15 Void My New Car Warranty?

It depends on the vehicle you drive and what your vehicle manufacturer's warranty policy is with respect to E15. According to the American Automobile Association (AAA), as of December 2012 only five percent of vehicles have been approved for E15 use.

To date, BMW, Chrysler, Nissan, Toyota and Volkswagen have said that their warranties will NOT cover fuel-related claims caused by the use of E15 in their vehicles. This position may or may not change going forward.

General Motors, Ford, Honda, Hyundai, Kia, Mazda, Mercedes-Benz and Volvo have said that E15 does NOT currently meet the fuel requirements as stated in their owner's manuals and that the use of E15 MAY void warranty coverage. In other words, they have not yet decided whether or not E15 is totally safe to use in their vehicles.

Though some studies have reportedly found that E15 can cause fuel system damage in some older fuel systems, extensive testing by the EPA and the Department of Energy on 2001 and newer vehicles has found that E15 causes no problems whatsoever.

A US House of Representatives bill (HR 3199) would require further testing of E15 before it goes into widespread use. The bill would call on the National Academies of Science to conduct a more extensive study of E15.

Since the jury is still out as to whether or not E15 can be safely used in certain vehicles (primarily older vehicles), you might want to avoid using E15 until further test results are available and/or the vehicle manufacturers who are uncertain about E15 have made up their minds one way or the other. We will keep you posted.

February 2013

Bill Proposed to Ban E15

SEMA is supporting legislation (S. 344) introduced in the U.S. Senate to ban the sale of gasoline containing 15 percent ethanol. The bill would overturn actions taken by the U.S. Environmental Protection Agency (EPA) two years ago to permit ethanol levels to rise from 10 percent (E10) to 15 percent (E15). The agency is only requiring a gas pump warning label to alert motorists that E15 could potentially cause equipment failure for vehicles older than model-year 2001.

"This legislation is necessary to protect auto enthusiasts by preventing damage to older vehicles and high-performance specialty components," said SEMA Vice President of Government Affairs Steve McDonald. "SEMA applauds Senators Roger Wicker (R-MS) and David Vitter (R-LA) for their efforts to correct by statute a flawed decision by the EPA. Unless enacted into law, E15 may soon appear at a gas station near you."

Those who are opposed to E15 say ethanol increases water formation that can then create formic acid and corrode metals, plastics and rubber. Older cars and certain high-performance specialty parts are not constructed with corrosion-resistant materials or able to tolerate the higher temperatures at which E15 may burn. Auto enthusiasts have complained for years about damage caused by E10, which is now in more than 90 percent of gas sold in the United States E15 would increase that risk by 50 percent. For classic cars that are infrequently driven, corrosion could eventually damage the engine, fuel line, fuel tank and exhaust systems.

Followup: The bill did not pass.

October 2018

Trump Orders EPA to Allow Year-Round Use of E15

President Trump told the Environmental Protection Agency (EPA) to revise their rules that currently restrict the use of E15 to winter months to reduce evaporative emissions. The new rules will allow the sale of E15 (a 15 percent blend by volume of gasoline and ethanol alcohol) year-round provided the fuel meets certain emission standards. The new rules should take effect by the summer of 2019.

For year-round use, E15 must meet the ASTM International 4806-10 standard for ethanol. In addition, its Reid Vapor Pressure (RVP) is limited to 9.0 pounds per square inch during the summertime gasoline volatility season (May 1 – September 15) so that MY2001-2006 motor vehicles can meet evaporative emissions standards with E15. Other seasonal and geographic requirements that would limit the RVP of gasoline to lower than 9.0 psi still apply (e.g. areas of the country that have a 7.8 psi summertime RVP standard).

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US EPA E15 Information

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Growth Energy - America's Ethanol Supporters

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