How E85 Ethanol Flex Fuel Works

By: Chuck Giametta

A E85 powered 2009 Chevrolet HHR. See pictures of alternative fuel vehicles.­
A E85 powered 2009 Chevrolet HHR. See pictures of alternative fuel vehicles
2009 Chevrolet HHR

Drivers jumping on the latest gas-saving bandwagon may be in for a shock when they see fuel-economy estimates for the newest darlings of Detroit: E85 ethanol flex-fuel vehicles. Run a new V6 Chevrolet Impala on good-old gasoline, and it'll get 21 miles per gallon in the city, 31 on the highway, according to Environmental Protection Agency (EPA) estimates. Burn E85 -- a blend of 85 percent of the alcohol-based fuel ethanol and 15 percent gasoline, which American automakers flaunt as their latest alternative-energy idea -- and the Impala's EPA numbers shrivel to 16 mpg city, 23 highway.

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It's no better with other kinds of flex-fuel vehicles, vehicles that can run on E85, 100 percent gasoline, or a combination of the two. Run a two wheel-drive V8 Ford F150 on regular unleaded gas, and the EPA says it'll get 14 mpg city, 19 mpg highway. Run it on E85 ethanol, and it gets 11 mpg city, 14 mpg highway. In other words, fill up on environmentally friendly E85 ethanol, and you'll get fewer miles per gallon than you would on gasoline.

Sound depressing? Not if you believe that what's bad for the E85 ethanol user is good for America's fuel strategy. After all, a mile driven on E85 ethanol fuel is a mile not driven on conventional gasoline. And that, according to President Bush and proponents of E85 ethanol, can help America end its dependence on foreign oil.

Joining these E85 ethanol boosters are General Motors and Ford, which have mounted massive new E85 ethanol support programs. Spurred by public and private efforts to pump up E85 ethanol demand, ethanol producers themselves are pouring billions of dollars into building new refineries.

As with any alternative-fuel idea, however, the E85 ethanol story is one of tradeoffs. It pits, for example, E85 ethanol's ability to lower air pollution because it burns cleaner than gasoline against the potential environmental costs involved in ethanol production.

We've highlighted some tradeoffs in E85 ethanol fuel economy (more about that later), but are there compromises in convenience and vehicle performance? These and other issues are thoroughly explored in the following sections:

  • E85 Ethanol Flex Fuel Explained About one-third of all gasoline sold in the United States contains some ethanol, typically in a ratio of 90 percent gasoline and 10 percent ethanol. E85 gets its name from the way it inverts that formula, at 85 percent ethanol and 15 percent conventional gasoline. We'll explain how ethanol is produced and why it's mixed with gasoline, and explore some of the controversy surrounding its place in environmental and public policy debates. Only a fraction of the cars and trucks on the road are "flex fuel" vehicles: those that can run on conventional gasoline or E85 ethanol fuel. You'll learn why that number is growing, and how you can determine whether your next new car or truck -- or maybe the one you already own -- is an E85 ethanol flex-fuel vehicle.
  • How Does E85 Ethanol Affect You? E85 ethanol flex-fuel vehicles have some special technology in them. We'll explain how that may affect their purchase and maintenance costs. The automakers say running a flex-fuel vehicle on E85 has no effect on performance. We'll share our real-world experiences to find out if that's true. And although the number of gas stations selling E85 ethanol fuel is growing, we'll explain why there are still so few of them, and why they are clustered in a few geographic areas. Finally, how does using E85 ethanol fuel affect your pocketbook? And should that be the determining factor in whether you decide to use it?

E85 Ethanol Flex Fuel Explained

National Ethanol Vehicle Coalition This cycle illustrates how plants, often corn, are turned into ethanol.

Ethanol is an alcohol-based fuel made by fermenting and distilling starch crops, corn mostly. Only a relative handful of renewable energy companies produce it, but virtually all the ethanol they generate comes from renewable crops grown on American farms. On­e acre of corn can be processed into about 330 gallons of combustible ethanol.

Proponents argue that mixing 85 parts ethanol with 15 parts gasoline to create E85 ethanol fuel helps stretch the earth's supply of oil, which is finite. Supporters, such as the Renewable Fuels Association, say E85 ethanol fuel expands the market for U.S. crops and creates jobs in agriculture and refining. By reducing oil imports, backers argue, ethanol eases the nation's trade imbalance and cuts down on the tax dollars and military resources needed to keep foreign oil flowing.


As for environmental benefits, the U.S. Department of Energy says vehicles fueled with E85 ethanol have lower carbon monoxide and carbon dioxide emissions than conventional gasoline or diesel vehicles. Ethanol is water soluble, non-toxic, and biodegradable. E85 ethanol contains far fewer potential contaminants than found in gasoline.

But for nearly every benefit ascribed to E85 ethanol, a detractor is ready with a counterpoint. For example, ethanol production requires burning non-renewable fossil fuels to plant, grow, and harvest the crops and operate refineries. A Cornell University agricultural expert says that, considering the energy costs of growing corn and converting it to ethanol, it takes far more energy to produce ethanol than it yields. (A University of California study, by contrast, insists modern farm efficiency means ethanol generates more energy than it requires to produce.) Critics say ethanol production diverts corn that could be used to feed animals and people, thus shrinking the supply of corn and raising the price of food.

As for environmental concerns, many new ethanol refineries are seeking ways to cut costs by using coal as an energy source. Most now run on natural gas. Coal costs less, but pollutes more. And the U.S. Environmental Protection Agency says that putting more E85 ethanol flex-fuel vehicles on the road will result in more airborne chemicals that create smog, threatening an increase in respiratory ailments.

Detractors also point to burdens on taxpayers. The federal government, along with some agricultural states, has for decades subsidized ethanol production under the banner of farm support. Critics say the main beneficiaries of the billions of dollars in tax exemptions and incentives are giant agribusinesses and corporate refiners. In 2003, Illinois became the first state to remove the sales tax on E85 ethanol fuel. And the federal government provides up to $30,000 in tax credits to gas stations that convert pumps to E85 ethanol fuel.

On the heels of an energy bill signed into law in 2005 that requires refiners to produce more ethanol over the next decade, President Bush has pledged federal dollars to fund additional research into new methods of ethanol production. At the same time, federal regulators anxious to ease administrative burdens on ethanol production have proposed relaxed limits on the amount of air pollution these refineries would be allowed to generate.

This groundswell of support has helped ignite a boom in the number of corn-to-fuel refineries. Some 40 new ethanol-production facilities are expected to come on line by mid-2007. That would bring the national number to slightly over 100, up from just 50 in 1996.

Surprisingly, all this action is directed at what, for now, is a relatively small number of vehicles. Of the roughly 250 million cars, trucks, SUVs, and minivans on America's roads, only about six million are capable of burning E85 ethanol. About half of these E85 ethanol flex-fuel vehicles are in commercial or government fleets.

The majority of private E85 vehicles come from Ford and General Motors, but certain Chrysler, Dodge, Jeep, Mercedes-Benz and Nissan models also are E85 ethanol-compatible. These vehicles have special components installed on the factory assembly line that monitor and compensate for the ethanol/gasoline mix. Their fuel systems are also fortified against the corrosive effects of E85 ethanol.

E85 Throughout the Years

Henry Ford built an ethanol-burning Model T before World War I, and over the years, thousands of fleet vehicles were modified to run on ethanol-based blends. U.S. automakers began making E85 ethanol-compatible components standard on certain models in 1998.

Over the past year, Ford, GM, and DaimlerChrysler have seized the E85 ethanol mantle as a fuel-saving technology and a way to support the environment and promote domestic agriculture. These manufacturers say they plan to put a combined total of 2 million additional E85 ethanol flex-fuel vehicles on the road each year starting in 2007.

They have lobbied Congress for support of E85 ethanol, and GM and Ford help fund campaigns to promote E85 ethanol use and convert gas stations to carry the fuel. GM is even offering owners of its E85 ethanol flex-fuel vehicles who live in Chicago and Minneapolis a $1,000 gas card for E85 ethanol purchases.

For 2007, 29 different models for sale in the U.S. are E85 ethanol flex-fuel capable. That's up from 20 for the 2006 model year. For 2007, GM will offer 17 E85 ethanol flex-fuel models totaling about 400,000 vehicles, compared to nine models in 2006. Ford expects to sell 250,000 E85 ethanol flex-fuel models in 2006.

Still, you'll need to look closely to identify one of these E85 ethanol flex-fuel vehicles. Some early E85 ethanol flex-fuel Fords carry a small road-and-leaf logo and decal reading "FFV," for Flexible Fuel Vehicle. GM identifies its E85 ethanol flex-fuel vehicles with yellow gas caps and "Flex Fuel E85" badges.

­The best ways to determine whether you have an E85 ethanol flex fuel vehicle is to consult your owner's manual or check for an identifying sticker inside the fuel door. A list of E85 ethanol flex fuel-compatible vehicles is also available from several Web sites, ­including and

On the next page, we'll go into more detail about how E85 affects the everyday driver and where this fuel can be found.


How Does E85 Ethanol Affect You?

Most E85 pumps are located in theMidwest, but they are popping upin almost all 50 states.

If you choose to purchase an E85 ethanol flex-fuel vehicle, or discover you already have one, you'll be pleased to learn it won't require any drastic changes in your driving habits. If you insist on using E85 ethanol fuel most or all of the time, however, and you will be compelled to make some compromises.

As the term "flexible fuel" implies, any E85 ethanol flex-fuel vehicle can run on 100 percent E85, 100 percent pump gasoline of any octane, or any combination of E85 ethanol and gasoline. The car's on-board diagnostic systems compensate for any of these blends to keep it running according to manufacturer's specifications.


Automakers spend an estimated $150 to make a vehicle E85-ethanol capable, but none charges customers more for an E85 ethanol flex-fuel vehicle compared to a gasoline-only counterpart. Neither do they vary horsepower ratings for E85 ethanol flex-fuel engines. E85 ethanol has an octane rating of 100-105, versus 85-95 for gasoline, but manufacturers do not tune E85 ethanol-capable engines for higher performance than their gas-only counterparts. This allows them to run efficiently on conventional gasoline.

On the road, real-world performance is indistinguishable. Consumer Guide's automotive editors road tested an E85 ethanol flex-fuel Impala on both 87 octane gasoline and E85 ethanol, and could not detect a difference in engine performance, smoothness, or sound.

Some E85 ethanol proponents say the blend keeps fuel systems cleaner than gasoline, for potentially lower long-term maintenance costs. Ford and GM have no special maintenance requirements for their E85 ethanol flex-fuel vehicles, but other manufacturers may require use of specific engine lubricants. Check your owner's manual or consult your dealer. Motorists fueling up with E85 ethanol should share that information with their dealer service department or parts supplier when ordering replacement parts.

Where To Find E85

Once you decide you want to jump on the E85 ethanol bandwagon, you may have trouble actually climbing aboard. Efforts by automakers and the government to increase the number of gas stations that carry E85 ethanol have raised their ranks by some 100 stations over the past year. Nonetheless, only about 800 of the nation's 180,000 gas stations carry E85 ethanol fuel. Another 200 or so E85 ethanol refueling stations are fleet or government sites not open to the public. Most locations are in Midwest corn belt states, where E85 ethanol production and sales have for years benefited from government supports.

As of November 2006, according to the U.S. Department of Energy, Minnesota led the nation with 300 E85 ethanol fuel sites, followed by Illinois with 132, Missouri with 63, Iowa with 56, and South Dakota with 50. Most states had fewer than a dozen. Alaska, Delaware, Hawaii, Maine, New Hampshire, New Jersey, Rhode Island, and Vermont had none. Go to for a list of stations that carry E85.

Once you pull up to an E85 ethanol pump, you aren't likely to find the price per gallon of E85 significantly different from that of 87-octane regular grade gas. While some Midwest service stations price E85 ethanol as much as 30 cents per gallon below regular-grade gas, the EPA in November 2006 listed the average price for a gallon of E85 ethanol nationally at $2.41, compared to $2.23 per gallon for regular-grade gasoline.

Supply, demand, and distribution costs figure among reasons E85 ethanol can be more expensive than conventional gasoline at the pump. Government and auto industry efforts to promote the fuel have increased demand for E85 ethanol, helping create a supply crunch at refineries. In addition, wholesale ethanol prices are increasing as oil companies stock up on the alcohol as a substitute for petroleum additives suspected of causing cancer. And E85 ethanol costs more to distribute than gas. The blend can't be pumped through petroleum pipelines because of the corrosive impact of its alcohol content, for example.

In the final analysis, of course, E85 producers and retailers are free to charge what they can to satisfy demand and make a profit. So you've found a station with E85 ethanol, decided the price was right, and you've filled the tank of your flex-fuel car or truck. How far will it take you?

Not as far as a tank of gasoline would. As the examples of the Impala and F 150 show, your fuel economy using E85 ethanol is lower than with gasoline. These are not isolated examples. Overall, depending on the vehicle, fuel economy with E85 ethanol is some 20 to 30 percent less than with gasoline. Consumer Guide's test Impala, for example, averaged 24.2 mpg on gasoline, but just 16.9 mpg in similar city/highway driving using E85 ethanol.

Looked at another way, a tank of E85 ethanol will take you only about 80 percent as far as you could drive on a tank of gasoline. On E85 ethanol, you'll stop more to refuel, have to plan ahead to make sure the station carries E85 ethanol, and perhaps pay more per gallon once you get there.

The difference in miles per gallon between gasoline and E85 ethanol has to do with E85 ethanol's lower energy content per unit of volume. Measured in British Thermal Units (BTUs), a gallon of E85 ethanol has only 72 percent of the energy in a gallon of gasoline. Go to to compare EPA fuel-economy estimates for the same flex-fuel vehicle running on E85 ethanol and on gasoline.

So we've seen that choosing an E85 ethanol flex fuel vehicle and running it on E85 ethanol may not be to your personal advantage in terms of convenience and fuel cost. But it won't affect vehicle performance. And once you consider arguments on both sides of this the complex issue, you may decide that buying a flex-fuel vehicle and running it on E85 ethanol is a personal gesture of support for American agriculture, alternative fuels, and energy independence.


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