February 2, 2006

New Ethanol Study Supports CTs and Cellulosic Ethanol

James Fraser of The Energy Blog has posted a useful synopsis and some interesting comments on a UC Berkeley study that corroborates findings made by Michael Wang at the Argonne National Laboratory last year. Excerpts from The Energy Blog are included below...


New Ethanol Study from UC Berkeley

The study found that the net energy ratio (energy out/energy in) is 1.2 for ethanol produced from corn and 8.3 for cellulosic ethanol produced from switchgrass. The net energy value (energy out-energy in) was calculated to be 4.5 MJ/liter for corn ethanol and 22.8 MJ/liter for cellulosic ethanol. In terms of environmental impact corn ethanol decreases greenhouse gases only 14% when compared to gasoline, while cellulosic ethanol has a much greater reduction of 88% . They also pointed out, as have others, that it takes less energy to produce ethanol than it does to produce gasoline.

From the study: To study the potential effects of increased biofuel use, we evaluated six representative analysis of fuel ethanol. Studies that reported negative net energy incorrectly ignored coproducts and use some obsolete data. All studies indicated that current corn ethanol technologies are much less petroleum-intensive than gasoline but have greenhouse gas emissions similar to those of gasoline. However many important environmental effects of biofuel production are poorly understood. New metrics that measure specific resource inputs are developed, but further research into environmental metrics is needed. Nonetheless, it is already clear that the large-scale use of ethanol for fuel will almost certainly require cellulosic technology.

Cellulosic Ethanol as being developed by Colusa, Iogen, and Xethanol, or alternately the BRI Energy process should be in commercial use by 2010. Whether to use biomass to make vehicle fuel or for CHP fuel will be the question after 2020-25. There is also the possibility that by this time the gasification/Fischer-Tropsh processes (BTL) such as the Shell/Choren process will be used to produce both electricity and fuel.

The paper which was published in Science and the spreadsheet model used to develop the data as well as links to the six studies that were compared are found here: ERG Biofuel Analysis Meta-Model.

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