Move over E85, here comes E15. EPA proposes adding more ethanol to gasoline blends

The Environmental Protection Agency (EPA) today announced its approval to raise the blend of ethanol contained in regular gasoline. The fuel would be available to use in cars from the 2007 model year and up. Pumps that dispense E15 will have to have special labels, which EPA also previewed.

The move comes in response to the Renewable Fuels Standard, which requires 36 billion gallons of ethanol to be produced by 2022 for blending with gasoline. Currently, ethanol is blended into gasoline in two forms: E85 and E10. E85 is 85 percent ethanol and 15 percent gasoline, and it can be used only in specially-designated flex-fuel vehicles. Far more common, E10 (10 percent ethanol and 90 percent gasoline) is designed to improve air quality in smoggy regions and can be used in all cars built since the early 1990s.

The problem with these approaches is that they currently only consume about 12 billion gallons of ethanol. To reach 36 billion gallons will require either the sale of exponentially more flex-fuel vehicles with significantly more pumps, or an increase in the percentage of ethanol allowed in normal gasoline, as we reported in 2007. About half the ethanol will come from corn, as most now does. The other half is supposed to come from cellulosic sources such as wood chips, switchgrass, or municipal waste.

That's what has been proposed by the Growth Energy, an ethanol industry trade group, which has asked the EPA for a waiver to blend up to 15 percent ethanol into conventional gasoline for newer cars, rather than just 10 percent. They have also asked for approval for older engines to run on a blend of 12 percent ethanol.

Groups representing automakers, farmers, environmentalists, and oil terminal operators have opposed the waivers and called for a Congressional hearing on the subject. Among other things, they are concerned about increasing the concentrations of ethanol, especially in older cars, because ethanol is corrosive. They cite studies that show ethanol can be harmful to emissions and fuel-system components in cars.

Some gasoline blenders, who fall directly under to the Renewable Fuels Mandate, are resisting the increase. Valero Energy and Marathon Fuels say they are hesitant to sell E15, because they don't want to be liable for damage to engines burning higher concentrations of ethanol.

One Detroit-based automotive engineer we spoke with on background said that automakers will have trouble making non-flex-fuel vehicles comply with emissions requirements, if the ethanol levels in a vehicle's fuel tank are inconsistent. Today's 10-percent standard is the maximum allowable, but lots of gasoline may be blended at 7 or 8 percent to stay safely below that cap. These variations can confuse the oxygen sensors in a car, which can make the fuel injection overcompensate and produce more pollution or even rough-running.

The EPA is scheduled to release the results of testing it has conducted on cars from the 2001 to 2006 model years next month. The agency may later issue an amendment to this ruling which would allow the use of E15 in those cars.

The ruling opens the door to more sales of E15, but in practice it may be months or years before it becomes more widely available. Some state regulations still inhibit higher ethanol blends, and underground gas tanks and other equipment would still need to be certified to store it. The EPA is taking public comments on its proposed waiver for 60 days.

Also read: EPA to propose 35 mpg, groups push for 60 mpg or even 70 mpg by 2025

See our guide to fuel economy for advice on saving gasoline. Learn about future technologies in our guide to alternative fuels.

—Eric Evarts