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Wednesday, 11 July 2007 00:00

The Naturalist's Corner: Ethanol

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Editor’s note: This is another in a series of columns by Don Hendershot about alternative energy


Ethanol is grain alcohol produced by fermenting biomass like corn. It was one of the first vehicle fuels produced in this country but like others fell by the wayside with the rise of cheap oil. Ethanol is primarily produced as blends with gasoline. Those blends containing a small about of ethanol like E10 — 10 percent ethanol, 90 percent gasoline — have been around for a number of years, known as gasohol. Any gasoline vehicle can run on E10 and E10 is not considered an alternative fuel under the Energy Policy Act.

Engine modifications are required when you get to blends above 10 percent ethanol. Vehicles that run on these higher blends are known as “flex-fuel” vehicles (FFVs). Since no after market conversion kits are sold the only way to get a FFV is from the manufacturer.

While there are many of these being made (an estimated 5 million on the road today) there is a little twisted logic at work. Automakers get CAFÉ (Corporate Average Fuel Economy) credits for producing FFVs. This loophole allows automakers to rate a FFV that gets roughly 13 mpg at 23 mpg.

So instead of opting for smaller more aerodynamic fuel-efficient vehicles as they do with hybrids, automakers are making their gas-guzzlers FFVs. Examples of today’s FFVs include Chevrolet Suburban (avg. 16 mpg), Dodge Ram 1500 pickup (avg. 14 mpg), Ford F150 pickup (avg. 16 mpg) and Nissan Titan pickup (avg. 16 mpg).

This is a doubled edge sword with regards to conservation because these CAFÉ standards apply whether the owner of the vehicle uses ethanol or not. Secondly ethanol is less fuel-efficient than gasoline so a vehicle that averages 16 mpg on gasoline will likely average 12-13 mpg on ethanol.

Almost all of the U.S.’s ethanol comes from corn. The recent energy bill that just passed the Senate calls for 36 billion gallons of ethanol per year by the year 2022. If it were produced from corn it would require almost all the corn grown in the U.S. today.

Other biomass works for ethanol production. Brazil gets most of its ethanol from sugarcane, other sources such as wood chips and switch grass are also being considered. But there is no doubt that the infrastructure in place today heavily favors corn as the primary source of ethanol in this country.

Some of the pros regarding ethanol:

• It is a renewable resource that can be produced domestically.

• Tailpipe carbon emissions are lower than gasoline engines.

• While corn is, no doubt, the number one source for ethanol in the U.S. today, it can be made from almost any biomass.

Some of the cons regarding ethanol:

• Ethanol is less fuel efficient.

• It may produce more nitrogen emissions.

• Currently costs more to produce than gasoline.

• More corrosive than gasoline could cause greater engine wear.

• The intensive agriculture practices required to produce large quantities of ethanol may have wide spread environmental and socio-economic impacts.

The debate regarding the environmental effects of ethanol as an alternative fuel is as volatile as the fuel itself. There seems to be consensus that tailpipe emissions of carbon monoxide are less and nitrogen oxides are more than conventional gasoline engines. Ethanol proponents say that ethanol is carbon dioxide neutral because the plants used to produce the fuel absorb as much CO2 while they are growing as the ethanol emits when it is used. Detractors say the equation isn’t as simple as that and point to the fossil fuel used to produce the ethanol.

E85 is getting easier for motorists to find but there are still only 600 or so E85 stations across the country and nearly half of those are in Minnesota and Illinois.

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