Ethanol vs Greenhouse Gases

In 2006, ethanol saved 0.054% of US greenhouse gas emissions. A 100 fold increase would bring us to 5.4%, still not enough. But 20% of the 2006 corn crop was used for ethanol, so a 100 times increase would require 20 times the entire corn crop, and cost a fortune. These numbers are 50% more optimistic than those from UC Berkeley's Sustainable Energy Lab. They are not difficult to check.

To calculate greenhouse gas (GHG) savings for ethanol we need to know how much GHG emission are reduced when 1 gallon of gasoline is replaced with ethanol. This key value has been reported recently in Science magazine (Jan '06) and the Proceedings of the National Academy of Sciences (July '06). The Science article is a survey (of all previous ethanol studies) done by a pro-biofuels group of professors in UC Berkeley's Energy and Resources group and its Sustainable and Appropriate Energy Laboratory. Their published value is a 13% reduction in GHG, but they corrected this value to 7.4% in May, 2006. The National Academy study found a 12% GHG reduction, and zFacts has used this more optimistic value.

The simple calculation of the 0.054% GHG reduction for the US is presented here: ethanol GHG, along with simple one-click documentation of all input values. The calculation takes into account the following factors.

1. Gasoline production and delivery uses fossil fuel, so saving a gallon of gas in the tank saves as much GHG as from burning 1.23 galllons of gasoline.

2. 8228 grams of CO2 are produced by burning a gallon of gasoline.

3. 1.53 gallons of ethanol has the energy of 1 gallon of gasoline.

4. 4.885 billion gallons of ethanol were produced in 2006.

5. 7.122 trillion grams of CO2e GHG emissions in 2004 (most recent value).

That's all it takes to prove corn-ethanol is a hopeless approach to fighting climate change. In the next two days, zFacts will show that corn ethanol does little for energy independence and is enormously expensive.