People are up in arms over recent EPA waivers that allow but do not require up to 15 percent ethanol to be blended into gasoline. The 15 percent blend, called E15, would be available only from blender pumps clearly labeled “Passenger vehicles only. Use in other vehicles, engines and equipment may violate Federal law.”
Here is the EPA’s list of vehicles that should not be fueled with E15:
- Vehicles with heavy-duty engines, such as school buses and delivery trucks
- Off-road vehicles, such as boats and snowmobiles
- Engines in off-road equipment, such as lawnmowers and chainsaws
- Model-year 2000 and older cars, light-duty trucks and medium-duty passenger vehicles (later changed to model-year 2007 and older)
Why do E10 and now E15 alcohol-gasoline blends exist? The Energy Independence and Security Act (EISA) of 2007 requires that renewable fuels be blended into transportation fuels and also mandates that the EPA ensures that these renewable fuels, from production to use, actually emit less greenhouse gas than the petroleum-based fuel they replace.
Two motivations behind EISA are:
1) to cut U.S. dependence on foreign oil;
2) to reduce production of greenhouse gas from vehicles.
ETHANOL IN GASOLINE: THE PROBLEMS
 Because ethanol contains one-third less energy per gallon than gasoline, adding ethanol to gasoline leans out the fuel-air mixture, possibly enough to cause damage. Several manufacturers of small engines have said they will not honor warranties if fuels containing more than 10 percent ethanol are used.
Recent-model automobiles have digital fuel injection capable of automatically compensating for this leaning effect of E15 fuel. “Yellow-cap” or “Flex-Fuel” vehicles, which make up about four percent of the U.S. auto/light-truck fleet, are able to compensate for fuels containing up to 85 percent alcohol (E85).
 Metal fuel-system parts can corrode as a result of exposure to alcohol. Fuel additives are sold to inhibit this. Solvency of alcohol in certain fuel-system plastics, rubber and seal materials used in older vehicles can lead to softening and swelling. Fuel additives cannot prevent this.
 Alcohol absorbs water from any source (even from the atmosphere). Once alcohol that is dissolved in gasoline has absorbed sufficient water, it can separate from the gasoline and settle to the bottom of the tank. If this separated water-alcohol mixture is drawn into the engine’s fuel-system, the engine will run lean and may misfire or stop running.
 Some fear that the E15 fuel remaining in the blender pump’s hose and pump, when mistakenly mixed into the small fuel volume of a motorcycle’s or other small engine’s tank, might result in a mixture lean enough to cause engine damage. To prevent this, EPA will require customers using the E15 blender pump to buy at least four gallons of fuel. This will dilute the fuel that remains in the hose and pump enough to make it harmless to your bike.
POLITICS OF ETHANOL
Biff! Pow! Sock-O! Grind those axes, everyone!
- Every gallon of corn-derived alcohol sold in motor fuel is two-thirds of a gallon of gasoline that the oil companies don’t sell. Do they like this?
- Corn states love alcohol in fuel because it drives up corn prices.
- Beef states hate higher feed prices.
- Hydrofracking has raised U.S. production of oil and gas, reducing concern over energy independence and cutting incentive to add alcohol to gasoline.
- The U.N. has asked the U.S. to suspend its use of corn to power automobiles as it drives up world food prices, especially in this drought year.
- Many ask why government should subsidize the ethanol industry.