Introduction to Is ethanol fuel really better for the environment than sticking with gas?

January 24, 2007
In the energy industry, the need for change is no longer debatable. Beyond the danger of complete dependence on foreign oil when global politics are at their most volatile in decades, the environmental impact of burning millions of gallons of fossil fuels faster than we can say "greenhouse gases" is beginning to sink into the general consciousness. So what's the answer? Some say it's hydrogen, which is a brilliant alternative but ultimately raises some complex questions about safety. Others point to natural resources like sunlight and wind as potential cures. But by far the darling of the moment in the renewable energy lobby is ethanol, and Washington seems to be jumping on the bandwagon in droves. How can you argue with the wisdom of powering our cars with yummy, bountiful corn?

Apparently, you can argue with it, and many people are. First, a quick primer on what ethanol is and how it's made.

Ethanol is grain alcohol. In the United States, it's usually made from corn. In Brazil, it's most commonly made with sugarcane. Ethanol can be made from other grains like wheat and barley, and you can even produce it from potatoes. There are a couple of ways to make fuel-grade ethanol, and one of the most common ones is the dry-mill method, which goes something like this:

  1. The corn (or other grain) passes through a grinding meal. It comes out as a powder.
  2. A mixture made of this grain powder, water and an enzyme enters a high-heat cooker, where it is liquefied. The enzyme helps to break down the grain compound to aide in the liquefaction process.
  3. The liquefied mash is cooled, and another enzyme is added to the mix. This enzyme converts the starch into sugars that can be fermented to create alcohol.
  4. Yeast is added to the sugar mixture to begin the fermentation process. The sugars break down to ethanol (a form of alcohol) and carbon dioxide.
  5. The fermented mixture is distilled. The ethanol separates from the solids.
  6. A dehydration process removes water from the separated ethanol.
  7. A small amount of gasoline is added to the ethanol in order to make it undrinkable. All ethanol used as a fuel must be made nonpotable.
Byproducts of this process, including distiller's grain and carbon dioxide, are both useful in the farming and ranching industry and may be sold by the ethanol-manufacturing plant for various purposes.

In its current status as a low-percentage fuel additive, the benefits of ethanol are obvious. Added in small amounts (typically one part ethanol, nine parts gasoline) to the gasoline that fuels our cars, it reduces greenhouse emissions like carbon monoxide and nitrogen oxides. Since ethanol contains a lot of oxygen in its chemical structure, it burns pretty cleanly. The addition of ethanol to the fuel mix also reduces the amount of fossil-fuel-based gasoline we consume when we drive, and any car can run on this 10-90 ethanol mix (called E10). The 85-15 ethanol mix (called E85) that only fuels special "flexible fuel vehicles" (FFVs) burns even cleaner, further reducing the release of harmful gasses into the atmosphere that can cause air and water pollution, global warming and smog. But only a relative handful of vehicles can run on this mix, and it's not commonly stocked in gas stations.

Ethanol seems like a dream come true for the energy crisis, and in some ways, it is. Ethanol.org reports that statistics out of the Argonne National Laboratory show an approximate 7-ton decrease in greenhouse-gas emissions resulting from the use of ethanol fuel in 2004 alone. But according to many experts in agriculture, making ethanol a major player in the fuel industry has serious drawbacks that many in the ethanol business, the "save the environment" business and the politics business are choosing to ignore.

The problem with using ethanol as fuel in a large-scale way comes down to two primary, related issues:

  • There's not nearly as much energy in ethanol as there is in gasoline.
  • To create significant amounts of energy from food crops would deplete the amount of land available for growing actual food for people to eat.

While most experts agree on these two points, they tend to differ in terms of degree. Cornell University professor of agriculture David Pimental calculates some very disturbing figures. According to Dr. Pimental, it takes more energy to produce a given amount of ethanol than there is energy available in that ethanol. According to his calculations, producing corn and processing it into 1 gallon of ethanol requires 131,000 BTUs of energy; but 1 gallon of ethanol contains only 77,000 BTUs. So producing ethanol actually creates a net energy loss. And since farmers are using fossil-fuel-powered equipment to plant, maintain and harvest the corn and are using fossil-fuel-powered machinery to process that corn into ethanol and then transport that ethanol to collection points (ethanol can't run in underground pipelines because it picks up damaging impurities), the ethanol industry is actually burning large amounts of gasoline to produce ethanol, and that ethanol contains far less energy than the gasoline they consumed to produce it.

But not all scientists agree with Pimental's analysis regarding energy efficiency. Dr. Michael Wang of the Argonne National Laboratory finds that it requires 0.74 million BTUs of fossil fuels to get 1 million BTUs of ethanol to market. That would mean a net gain in energy, not a net loss.

Energy efficiency aside, those in Pimento's camp actually don't see corn as a truly renewable energy source. Pimento estimates that powering a car for a single year using ethanol would require 11 acres of corn. Since corn fields in the United States take a while to replenish themselves due to both soil erosion and irrigation issues, 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.

One possible answer to what some see as the ultimately unworkable nature of grain-based ethanol as a primary fuel is something called cellulosic ethanol. Cellulosic ethanol is made from non-food products such as corn stalks, wood chips and switchgrass. If this tiny corner of the ethanol industry develops into a large enough producer, cellulosic ethanol could prove to be a viable, lower-cost compromise in the ethanol vs. gasoline debate.

For more information on ethanol and other renewable-energy options, check out the following links:

Sources

  • Barrionuevo, Alexei. "Springtime for Ethanol." The New York Times. Jan. 23, 2007.
    http://www.nytimes.com/2007/01/23/washington/23ethanol.html? _r=1&th&emc=th&oref=slogin
  • Ethanol.org
    http://www.ethanol.org/
  • Halperin, Alex. "Ethanol: Myths and Realities." BusinessWeek Online. May 19, 2006.
    http://www.businessweek.com/technology/content/may2006/ tc20060519_225336.htm
  • Segelkin, Roger. "Ethanol Fuel from Corn Faulted as ‘Unsustainable Subsidized Food Burning’." HealthAndEnergy.com.
    http://healthandenergy.com/ethanol.htm