UC Berkeley's Renewable and Appropriate Energy Lab, is pro-ethanol, and they do good work. They have reviewed about 10 of the best ethanol studies, corrected them, and produced the best compromise estimate. Their value for GHG reduction is even lower than the one used by zFacts. It would put the GHG savings at less than 0.1% in 2017 when corn ethanol has pretty much maxed out.
Berkeley put the GHG savings at 13% in their
Science article, then corrected it to 8%
Berkeley pdf
. Then the Academy of Sciences published a new study in July 2006
Academy pdf
, and came in at 12%. zFacts used the more optimistic 12%.
Using this value, the energy in ethanol, the amount of ethanol that USDA says can be produced in 2017, and DOE's total GHG emissions for the US, you will find a reduction of 0.13%. zFacts rounded that up to 2/10 of 1% to be generous in our headline. The bottom line for climate change and corn ethanol:
Besides failing to help with GHGs and having serious environmental problems, corn ethanol subsidies are very expensive, and the political backlash in the next few years, as production and
subsidies double, will damage the effort to curb global warming.