MIT Study Confirms Ethanol Benefits

Cindy Zimmerman

MIT It’s unlikely to be the final word on the subject, but a new MIT analysis shows that the energy balance between ethanol and fossil fuel is actually so close that several factors can easily change whether ethanol ends up a net energy winner or loser.

In other words, it depends on what you figure into the equation.

GroodeAccording to MIT, Tiffany A. Groode, a graduate student in MIT’s Department of Mechanical Engineering, performed her own study, supervised by John B. Heywood, Sun Jae Professor of Mechanical Engineering.

Based on her “most likely” outcomes, she concluded that traveling a kilometer using ethanol does indeed consume more energy than traveling the same distance using gasoline. However, further analyses showed that several factors can easily change the outcome, rendering corn-based ethanol a “greener” fuel.

Among those factors is system boundary, or which energy-using factors of production are included and excluded in determining energy efficiency. Groode compared several different studies that used different factors, including the 2003 Pimental study which counts such energy-consuming inputs such as the manufacture of farm machinery.

“The results show that everybody is basically correct,” she said. “The energy balance is so close that the outcome depends on exactly how you define the problem.” The results also serve to validate her methodology: Results from the other studies fall within the range of her more probable results.

Groode also did energy analyses of corn stover and switchgrass and found that fossil energy consumption is far lower with these two cellulosic sources than for the corn kernels.

“I view corn-based ethanol as a stepping-stone,” said Groode. “People can buy flexible-fuel vehicles right now and get used to the idea that ethanol or E85 works in their car. If ethanol is produced from a more environmentally friendly source in the future, we’ll be ready for it.”

Read more from MIT.

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