Carbon cloud over a green fuel

Late last year in Goldfield, Iowa, a refinery began pumping out a stream of ethanol, which supporters call the clean, renewable fuel of the future.

There's just one twist: The plant is burning 300 tons of coal a day to turn corn into ethanol - the first US plant of its kind to use coal instead of cleaner natural gas.

An hour south of Goldfield, another coal-fired ethanol plant is under construction in Nevada, Iowa. At least three other such refineries are being built in Montana, North Dakota, and Minnesota.

The trend, which is expected to continue, has left even some ethanol boosters scratching their heads. Should coal become a standard for 30 to 40 ethanol plants under construction - and 150 others on the drawing boards - it would undermine the environmental reasoning for switching to ethanol in the first place, environmentalists say.

"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.

The reason for the shift is purely economic. Natural gas has long been the ethanol industry's fuel of choice. But with natural gas prices soaring, talk of coal power for new ethanol plants and retrofitting existing refineries for coal is growing, observers say.

"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?

Such questions arrive amid boom times for America's ethanol industry.

With 97 ethanol refineries pumping out some 4 billion gallons of ethanol, the industry expects to double over the next six years by adding another 4.4 billion gallons of capacity per year. Tax breaks as well as concerns about energy security, the environment, and higher gasoline prices are all driving ethanol forward.

The Goldfield refinery, and the other four coal-fired ethanol plants under construction are called "dry mill" operations, because of the process they use. The industry has in the past used coal in a few much larger "wet mill" operations that produce ethanol and a raft of other products. But dry mills are the wave of the future, industry experts say. It's their shift to coal that's causing the concern.

Scores of these new ethanol refineries are expected to be built across the Midwest and West by the end of the decade, and many could soon be burning coal in some form to turn corn into ethanol, industry analysts say.

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