Thursday, October 06, 2005

Ethanol and the Environment

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It would be difficult to live here in the heart of corn country and not like the idea of ethanol, the corn-based fuel that can substitute for gas in our cars. But as citizens who foot the bill for energy policy and who value a healthy environment for ourselves and our children, we have an obligation to look more closely at what we’re buying when it comes to energy alternatives. As it is currently produced, ethanol delivers far less than the hype surrounding it promises.

Marketers of ethanol term it a “renewable” resource, trading on the idea that it is simply energy captured from the sun made available for use as fuel by distilling grain into alcohol. What most people don’t realize, though, is that large quantities of fossil energy are used to grow corn, and still more is required to power the distilling process. Indeed, whether the system as a whole produces more energy than it consumes is still open to debate. In any case, even under the rosiest scenario, only a fraction of the energy available in a given quantity of ethanol can realistically be labeled “renewable.” The rest is, in effect, repackaged fossil fuel.

Ethanol has also been touted as environmentally friendly, because as an additive to gas it alters the composition of engine exhaust, reducing emissions of certain pollutants. What ethanol does not do is significantly reduce nitrogen oxides, the most important smog-causing tailpipe emission from a late-model car. The best way to reduce smog-producing tailpipe emissions is to reduce the amount of fuel cars burn in the first place.

Beyond that, if we’re going to gauge ethanol’s environmental friendliness, we really need to look past what’s coming out of our tailpipes. The true environmental costs of adopting ethanol as a fuel are in fact much broader. They include the environmental impacts of growing corn, such as habitat alteration, soil erosion, and pollution from pesticides, herbicides and fertilizers, as well as the environmental impacts of the distilling process. Ethanol plants have been very slow to adopt air pollution controls, and they use enormous quantities of water, itself a finite resource.

When we’re asked to buy the idea that ethanol represents a homegrown alternative to gas, we are also asked to buy the implication that using it can help free us from the geopolitical entanglements associated with our dependence on oil. But ethanol replaces only about two percent of the gasoline we currently use, and even greatly expanded production will not reduce our demand for oil significantly.

As in the case of air pollution, if we’re serious about reducing our dependence on oil, we can make greater strides toward that goal by adopting higher standards for fuel efficiency.

A special thanks to Walt Robinson from the Department of Atmospheric Sciences for Assistance with today’s program.