Corn Ethanol's Greenhouse Gas Emission Reduction Better Than Thought, New Study Shows
photo: Ryan via flickr
Considering the bad rep corn ethanol has gotten in the past year and a half or so, this news may fall on deaf ears, but a new study coming out of the University of Nebraska-Lincoln and published in the Journal of Industrial Ecology says that we have underestimated the potential of corn ethanol to reduce greenhouse gas emissions as compared to gasoline. This research shows that on average, corn ethanol produces emissions 51% lower than gasoline. Here’s why:Energy Returned on Energy Invested Better Too
Although the study did not take into account the effects of indirect emissions, such as land use changes, because of improvements in crop and soil management, as well as corn hybrids which allow for steadily increased crop yields,
The ethanol industry currently is producing a fuel that is 48 to 59 percent lower in direct-effect lifecycle greenhouse gas emissions than gasoline. That's two to three times the reduction reported in earlier studies that did not take into account recent advances in corn-ethanol production.
The net energy ratio, which averaged 1.2 to 1 in earlier studies, is 1.5-1.8 to 1 in the recent research, [report co-author Kenneth] Cassman said. That means that for every unit of energy it takes to make ethanol, 1.5 to 1.8 units of energy are produced as ethanol. (Cattle Network )
The authors of the report say that this means that, taking this into account, corn-based ethanol moves closer to the theoretical potential of cellulosic biofuels; and, because of these larger greenhouse gas reduction estimates, there is a “greater buffer for inclusion of indirect-effect land-use change emissions while still meeting regulatory GHG emission targets."
Industrial Agriculture’s Negative Effects
The report didn’t go into wider-ranging effects of the industrial agriculture dominant in the US, such as loss of biodiversity, fertilizer run-off, etc. (and whether industrial agriculture is really the best method of raising food, the UN doesn’t think so, and I suppose that’s all a bit beyond the research brief here) but at least corn ethanol fares a bit better in this study than in previous estimates.