An Iowa refinery began turning corn to ethanol last year by burning 300 tons of coal a day -- the first US plant of its kind to use coal instead of cleaner natural gas.
"If the biofuels industry is going to depend on coal, and these conversion plants release their CO2 to the air, it could undo the global warming benefits of using ethanol," says David Hawkins, climate director for the Natural Resources Defense Council in Washington.
"'It just made great economic sense to use coal,' says Brad Davis, general manager of the Gold-Eagle Cooperative that manages the Corn LP plant, which is farmer and investor owned. 'Clean coal' technology, he adds, helps the Goldfield refinery easily meet pollution limits -- and coal power saves millions in fuel costs.
Yet even the nearly clear vapor from the refinery contains as much as double the carbon emissions of a refinery using natural gas, climate experts say. So if coal-fired ethanol catches on, is it still the 'clean, renewable fuel' the state's favorite son, Sen. Tom Harkin likes to call it?"
Thanks to Jean Brocklebank
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Does Ethanol Produce Net Energy?
Even apart from the use of coal, some studies have found that it takes so much fossil fuel to produce corn in the US that ethanol involves a net loss of energy.
David Pimentel of Cornell University has added up the energy cost of producing the corn and converting it to ethanol, and has concluded that:
--the energy cost of producing one gallon of ethanol is 131,000 BTUs
--the energy value of one gallon of ethanol is 77,000 BTU.
The energy in the ethanol is less than 59% of the energy used in producing it.
By contrast, the USDA says that ethanol does produce net energy and estimates that the energy in the ethanol is 124% of the energy used to produce it. Even this favorable estimate means that producing one gallon of ethanol uses over .8 gallons of fossil fuels, so ethanol is far from being a clean fuel in terms of CO2 emissions.
Charles Siegel