Tuesday, May 13, 2008

The Efficiency of Ethanol; Is it Worth Producing?

We've all heard the comments that it takes almost as much energy to produce Ethanol as Ethanol provides. How true is this?

An article in the October 2007 National Geographic Magazine provides a lot of interesting information.

We will group ethanol into four categories:
  1. Corn Ethanol:
    "Nearly all the ethanol in the U.S. is brewed from yellow feed corn. Proliferating ethanol distilleries are already competing for corn with meat producers, driving up prices. Most ethanol is sold as a gasoline additive or, in the Midwest, as E85 (85 percent ethanol, 15 percent gasoline)."
  2. Cane Ethanol:
    "Brazil rivals the U.S. in ethanol production because sugarcane yields 600 to 800 gallons an acre, twice as much as corn. The stalk is 20 percent sugar - fermented to make the alcohol - and the waste cane can be burned to power the distillery, lowering fossil-fuel use."
  3. Biodiesel:
    "Chemically altering plant oils to make biodiesel takes less energy than distilling corn into ethanol; the fuel's main drawbacks are low yield and high cost. Germany is the world's leading producer, relying on canola oil; U.S. biodiesel comes from soybeans."
  4. Cellulosic ethanol:
    "Perennial prairie grasses like switchgrass, grown on land unfit for other crops, could replace up to 13 percent of the world's oil consumption - if an efficient way to turn cellulosic plant matter into ethanol can be developed."

Energy Balance

The Energy balance involves a number that compares the fossil-fuel energy used to make the fuel (input) compared with the energy in the fuel (output).

Now, we can compare the four types of ethanol.
  1. Corn Ethanol: Input=1, Output=1.3
  2. Sugar Cane Ethanol: Input=1, Output=8
  3. Biodiesel: Input=1, Output=2.5
  4. Cellulosic Ethanol: Input=1, Output=2 to 36 (depending on production method)

How efficient is Ethanol?

So with regards to Corn Ethanol, it is true that it takes almost as much fossil fuel (1 unit) to produce the energy in Corn Ethanol (1.3 units).

However, other types of ethanol, such as Sugar Cane Ethanol shows more promise.

And in a recent post, we highlighted the growth in Brazil as an agricultural powerhouse.

Energy Content

Comparing Gasoline to ethanol, Ethanol produces 67% of the energy content as Gasoline.

Comparing Diesel to Biodiesel, Biodiesel produces 86% of the energy content as Diesel.

Greenhouse Gas Emissions
  1. Corn Ethanol: 22% less
  2. Cane Ethanol: 56% less
  3. Biodiesel: 68% less
  4. Cellulosic Ethanol: 91% less

Production Quantities
  1. Corn Ethanol in U.S.: 4.86 billion gallons (2006)
  2. Cane Ethanol in Brazil: 3.96 billion gallons (2005)
  3. Biodiesel in Germany: 0.5 billion gallons (2005)
  4. Cellulosic Ethanol: Still in development

Production Cost
  1. Corn Ethanol (U.S.): $1.09 (Oct 2007)
  2. Cane Ethanol (Brazil): $0.87 (Oct 2007)

Sources of Cellulosic Ethanol
  1. Agricultural residues (leftover material from crops, such as the stalks, leaves, and husks of corn plants).
  2. Forestry wastes like wood chips and sawdust from lumber mills, tree bark.
  3. Paper Pulp
  4. Fast-growing prairie grasses, such as switchgrass, which require less energy (tractors, fertilizers, etc.) and can grow on marginal land.

Role in Food Inflation

Ethanol does play a role in food inflation. Cellulosic Ethanol seems like an interesting alternative that will affect food inflation less since we will not be using crops that we use as food.

We expect further research to be done in this area.

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