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Ask the Ecologist:

by Belle Bergner

Q: Is ethanol really an environmentally sound alternative to regular car fuel?

A: There are four main ecological issues with ethanol: the energy, water consumption, and land required to produce ethanol are the three major impacts on the production side, and the greenhouse gas emissions coming out of the tailpipe is the fourth.

First, let’s consider energy. One camp of researchers including Dr. David Pimental at Cornell University have calculated that it takes more energy to create ethanol than what we get out of it as car fuel. Farmers are using fossil-fuel-powered equipment to plant, maintain and harvest the corn and are using similar carbon-emitting machinery to process that corn into ethanol and then transport it to collection points. (The corn-based fuel can’t run in underground pipelines because it picks up damaging impurities.) So the production of this gasoline-alternative actually requires the burning of large amounts of gasoline.

In the other camp, Dr. Michael Wang from Argonne National Laboratory finds that one unit of ethanol requires 0.74 units of fossil fuels including transportation costs. That would mean a net gain in energy, not a net loss. A research group from UC-Berkeley also calculates that ethanol is more energy efficient than petroleum production.

Now let’s consider water. According to a 2006 publication from the Institute for Agriculture and Trade Policy, ethanol requires an average of 4 gallons of water per 1 gallon of ethanol produced.

How about the land required for corn production? Corn fields take a while to be replenished due to both soil erosion and irrigation issues, so those acres would be out of commission for a period of time, meaning no corn for ethanol and no usable land for other food crops. To sustain an ethanol-based fuel industry, more and more farm land would have to be set aside for corn alone. The ultimate result could be a shortage of domestically grown food and higher prices at the supermarket for all sorts of produce.

And what’s happening at the end of the exhaust pipe? It turns out that ethanol is only 10-15% more efficient than fossil fuel, thereby saving just a slim margin in greenhouse gas emissions.

One possible solution is to develop cellulosic ethanol which is made from non-food products such as corn stalks, wood chips and switchgrass. This is a much more expensive process but it is in the early stages of development and may become more affordable. The water and energy requirements are unclear because of the limited availability of public data on this technique.

To minimize the amount of water required, ethanol plants could be sited next to wastewater treatment facilities so that the ethanol plant can reuse the greywater from these facilities, which also reduces the energy consumption requirements by reducing the water pumping needs.

Unless the issues described here are resolved, the answer to your question appears to be no.

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Riverwest Currents online edition – July, 2007