The Magliozzi's first point out the difficulty of calculating what constitutes the elements in producing the fuel. Scientists agree that the energy to plant the corn and processing it into starch should be in the equation. They disagree, though, if the energy to manufacture the tractor used in processing corn should be included as well. Also, converting corn into ethanol creates various bi-products such as corn oil. When the energy producing such products are entered into the equation, the shortfall vanishes. Tom also reminds readers that the equation only considers corn as the source of ethanol. Sugar cane, which can also be converted into the fuel and is more energy efficient, can wildly change the figures.
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[Source: The Sun News via Myrtle Beach Online, picture by Singer]