Brazil study highlights benefits of mid-level ethanol blends

By Growth Energy | May 08, 2014

A recent report published in Nature Geoscience entitled, “Reduction in local ozone levels in urban Sao Paulo due to a shift from ethanol to gasoline use,” claims a 20 percent reduction in ozone when drivers in Brazil switched from ethanol to gasoline.  A review conducted by Steve VanderGriend at the Urban Air Initiative shows the Nature Geoscience title is misleading and the study actually proves the benefit of mid-level blends of ethanol.

First, the analysis notes, it’s important to point out that in Brazil where the study was conducted, when the authors refer to gasoline it is actually a blend of 25 percent ethanol.  All fuel sold in Brazil must contain at least 25% ethanol, and clear gasoline is not even available for purchase in Brazil. Thus, the study and all the press make it appear that authors studied pure gasoline versus ethanol and that is not the case. 

Brazil has two fuels, E25 (25 percent ethanol, 75 percent gasoline) and what the study calls “ethanol,” which is in fact hydrous ethanol (known as E100: 95 percent ethanol and 5 percent water). Most vehicles sold in Brazil are flex fuel and can run on either fuel blend and drivers choose their fuel based on price. 

Ozone emissions are highest with pure gasoline and also hydrous ethanol (95 percent ethanol with 5 percent water). However, emissions are reduced when you add ethanol to gasoline. This is why this study found that Brazil saw ozone emissions improve when drivers started using E25 instead of hydrous ethanol (E100). Therefore, the notable results of this study are that mid-level ethanol blends do in fact improve ozone emissions.

With 70 percent of Brazilian fuel being E25 during the timeframe of this study, the study actually demonstrated Brazil has one of the cleanest burning fuels available, and it also highlighted the value of mid-level ethanol blends. 

The bottom line is that mid-level blends of ethanol have been proven to decrease emissions, and if the United States is serious about taking the necessary steps to reduce harmful emissions, it is time that mid-level ethanol blends are offered to consumers. Not only will consumers benefit from the availability of a choice and savings at the pump, but when they choose the less expensive, homegrown fuel, they will also be decreasing harmful emissions that are detrimental to our children and future generations.