I came across an interesting brochure from BMW that is titled “Beyond octane: How additives in gasoline are affecting your BMW’s performance”. We have scanned and posted the one side of this brochure below (click on image for a larger view).
The text that reads
“In combustion, ethanol provides less energy than gasoline, resulting in reduced fuel economy. When ethanol burns inside the engine, it tends to form a weaker mixture that may cause misfire, rough idle and cold start issues in your vehicle. In addition, engine components may deteriorate over time when in contact with ethanol”.
This is hardly an endorsement for this fuel component that is promoted as one way to reduce carbon dioxide emissions.