Wednesday, April 26, 2006

Gasoline & Ethanol

I read the headline Bush Eases Environmental Rules on Gasoline. Is this a good or a bad thing? Supposedly part of the reason for the recent increase in gasoline prices has to do with refiners converting from a process that uses one set of additives to a different process that uses another set of additives (including ethanol) to help reduce air pollution in the summer. So perhaps easing the rules about including ethanol will help lower gasoline prices. Of course, since I commute on a bicycle, the price of gasoline isn't a big worry for me.

But what about the environmental impact? Where I live the air quality is fine, so I'm more concerned with global carbon dioxide emissions. A recent meta study done here at berkeley found that using ethanol in gasoline significantly reduced the ammount of petrolium required to produce that gallon of gasoline. This is very significant as previous studies had suggested the opposite. But this conclusion was only true when they carefully considered how the "waste" products of ethanol production are used to displace other products that would otherwise require petrolium to produce. (This raises the concern that if ethanol were used on a large scale, would there still be useful applications for the byproducts? Or would it eventually revert to no net change in petrolium usage?) So this study concludes that including ethanol in gasoline is useful in the sense of reducing petrolium consumption, minimizing dependance on foreign oil, etc.. However, that same metra-study was unable to determine whether the effective change in the ammount of carbon being released into the atmosphere when petrolium was replaced by ethanol in gasoline was positive or negative. (They did estimate that it's likely a 10-30% effect.) So even switching all our cars to using E85 (85% ethanol, 15% normal gasoline), won't solve the problem of green house gases. (The authors suggest growing biofuels form plants other than corn that could result in less carbon emissions, but that is even farther in the future than large scale usage of corn ethanol.)

My conclusion... It's not clear whether easing these "environmental rules" will result in an increased or decreased prices of gasoline. And it's not clear whether easing thse environmental rules will result in an increased or decreased level of carbon emissions.