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. Last Updated: 07/27/2016

U.S. Debates Ethanol as Alternative Energy Source

APA man in Minnesota pumping E85, a blend of corn-based ethanol with petroleum.
WASHINGTON -- U.S. politicians are hailing ethanol, a corn-based gasoline additive, as a boon to the environment and a way to reduce the country's dependence on foreign oil.

But ethanol also comes with its own environmental problems, and scientists disagree over whether producing ethanol actually uses more fossil energy than it replaces.

The Senate this week will decide whether to double the amount of ethanol to be used in gasoline to 19 billion liters per year. Critics say the plan is just one more subsidy for corn growers. Supporters make the case that the proposal is essential to an energy policy that is less reliant on oil.

"It will reduce our dependence on foreign oil. It will protect the environment," Senate Majority Leader Bill Frist says.

There is skepticism about those claims. Ethanol's benefits are "a mixed bag," says Blake Early, a lobbyist for the American Lung Association.

Ethanol's clearest air quality benefit is that it significantly cuts carbon monoxide, he says.

But ethanol also releases more nitrogen oxide, a key element of smog, and evaporates more easily than gasoline, causing still other air pollution problems, Early says.

And some scientists now say that ethanol, while not as troublesome as a methanol-based additive known as MTBE, also may complicate cleaning up gasoline spills into waterways and groundwater.

"It certainly is not all that benign," says Tom Curtis, an official of the American Water Works Association, which represents professionals in the drinking water supply business.

He cites research indicating that gasoline plumes containing ethanol degrade more slowly in groundwater than plumes of only gasoline. Toxic chemicals such as benzene in ethanol-blended gasoline disperse more widely and take longer to degrade, the studies found.

These studies "are far from conclusive" and should be pursued further, says Monte Shaw, a spokesman for the Renewable Fuels Association, which represents the ethanol industry.

But he maintains that because ethanol replaces 10 percent of the gasoline, there is also less benzene and other toxic chemicals -- normally found in gasoline -- going into the water in the first place.

Ethanol supporters emphasize that it is a motor fuel made in the United States and that it is not a fossil fuel -- particularly from another country.

But opponents say it takes more energy to produce a liter of ethanol than it yields. Cornell University agricultural scientist David Pimentel says ethanol, when made from corn, should not even be considered a renewable fuel -- and actually provides little help on global warming.

It takes large amounts of nonrenewable natural gas, coal, and oil to make fertilizer and grow the corn, process ethanol and transport it in trucks and rail cars.