A new study from a Stanford University scientist suggests that burning large quantities of ethanol might actually promote more smog, even as it reduces greenhouse gas emissions. I have a healthy respect for unintended consequences, and the only surprising aspect of this result is that it should pop up now, after so many decades of blending ethanol into gasoline. Coming as this does in the midst of a growing debate about the tradeoffs between ethanol and food supplies--a topic that has apparently caught the attention of Venezuelan President Hugo Chavez--it complicates the picture for our de-facto primary alternative energy strategy.
Engineers have known for a long time that ethanol increases evaporative emissions from gasoline, thus boosting the local concentration of ozone precursors in the air we breathe. That was one of the factors that led refiners to favor MTBE over ethanol, until the unintended consequences of the former, in terms of groundwater contamination and odor, became clear. The Stanford study sheds new light on what happens to ethanol molecules in the atmosphere. If this finding is confirmed by other researchers, it is likely to create additional obstacles for E-85, besides infrastructure. It might also generate more interest in a process for turning corn and other biomass into clean-burning propane, which until ethanol's recent popularity was our most successful "alternative fuel."
E-85 proponents might be skeptical of the study's results, because of their coincidental timing--just when ethanol is taking off--or the connection between Stanford and ExxonMobil. However, the statement from Senator Feinstein's office suggests that officials are taking it seriously. Whatever the final outcome, this is a useful reminder that every large-scale energy alternative has consequences that must be weighed carefully against those of the status quo, to ensure that we get the most benefit from our investment of time and treasure, and to avoid costly dead ends.
By the way, Energy Outlook got a nice plug from the Wall Street Journal's blogroll on Tuesday. I'd like to welcome any new readers that found this site as a result.