Car Talk: Is Ethanol Energy Efficient?


Tom and Ray Magliozzi, known to the world at large as "Click and Clack," the hosts of NPR's weekly Car Talk program, recently addressed the controversial issue of ethanol efficacy (something we've covered before). According to a listener's letter,131,000 British thermal units (BTUs) are needed to produce a gallon of ethanol. However, that gallon only produces 77,000 BTU of energy. The listener wonders if the 54,000 BTU shortfall per gallon is truly cost-effective compared to gasoline, considering that ethanol goes for about 10% (or something like 30 cents a gallon) cheaper than the petroleum derivative. The Magliozzis first point out the difficulty of calculating the cost of producing the fuel; they agree that the energy to plant the corn and processing it into starch should be in the equation, but what about the energy needed for things like the production of the tractor used to process it? Ethanol production from corn also creates byproducts, like corn oil and gluten feed, which are valuable (albeit not fuel-related) commodities; considering all of these variables can eventually cancel the shortfall. Tom also reminds readers that the equation only considers corn as the source of ethanol; use more energy efficient fuels like sugar can, and it's a whole new ballgame. So, short answer: umm, hard to say. Like Tom says, "if guys with degrees in chemical engineering can't agree on the answer, how the heck are we supposed to know who's telling the truth?" Listen to the whole debate over at their website. ::Car Talk via ::AutoblogGreen