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Seven Reasons Why Testing Mid-level Ethanol Blends Matters

By Coleman Jones
Biofuels Implementation Manager

The question of raising the amount of ethanol blended into gasoline is back in the news with the filing of a petition to allow as much as 15 percent ethanol to be mixed into gasoline. GM is a big supporter of ethanol as an alternative fuel to help reduce petroleum use, but with respect to mid-level blends, there is a lot of testing that needs to happen before such a change is made.

This testing is important for two reasons: mid-level ethanol blends could affect the control systems of all kinds of unsuspecting equipment, and ethanol is more corrosive than gasoline.

Most of the gasoline for sale in the U.S. today is blended with 10 percent ethanol. Some pumps are labeled this way and others are not. That’s ok, because vehicles manufactured since 1980 are engineered to tolerate up to 10 percent ethanol. E10 typically has no impact on the fuel system, its components or how they operate.

We don’t know whether the same will be true for E15. There are seven areas that the auto, oil and small equipment industries agree should be tested before changing composition of the fuel.

  • Catalyst durability, which is especially significant because testing in Australia demonstrated catalyst deterioration as a result of prolonged mid-level blend (E20) use in some vehicles.
  • Engine and fuel system durability. This is important both because many of these components are upgraded on U.S. and Brazilian vehicles to be compatible with ethanol; and because small engines are particularly vulnerable to fuel changes.
  • On-board diagnostics, which are used in many states to monitor emissions compliance.
  • Tailpipe emissions. Testing is important to see how mid-level blends will perform under stringent emissions standards required in California and the Northeast states.
  • Evaporative emissions system durability.
  • Emissions inventory and air quality modeling.
  • Operability, which is, again, a particular concern for small engines.

The only full durability testing for mid-level blends was done on E20 six years ago in Australia. The outcome of those tests showed catalyst performance degradation in 40 percent of the vehicles tested on E20. The catalyst is the part of the engine that converts pollutants and keeps them from exiting the tailpipe.

When it comes to meeting the Renewable Fuel Standard that was part of the 2007 Energy Independence and Security Act, we think widespread use of E85 is the best and likely the only way to meet the 36 billion gallons of ethanol in 2022.

We really want to see biofuels succeed in the marketplace. And we’re continuing to familiarize people with ethanol’s advantages – fewer greenhouse gas emissions and reduced reliance on petroleum. We know ethanol has lower energy density and that it takes the correct pricing to make up for the 20-25 percent fewer miles per gallon, but it is definitely part of the overall fuel solution.

The best way to ensure that ethanol keeps a good reputation is to execute the comprehensive durability testing and use the data to determine the makeup of tomorrow’s gasoline.

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