I didn't know this. Got a link to a source?
I am not sure which fact is being researched. Google it and if you can't find it, I'll get the link for you.
TMc.
Ethanol has 76,100 BTU's per gallon
Gasoline has 114,100 BTU's per gallon
Less energy available means it take more gallons to move the car the same amount.
http://www.nafa.org/Content/NavigationMenu/Resource_Center/Alternative_Fuels/Energy_Equivalents/Energy_Equivalents.htm
Even when specifically designed to run on ethanol, vehicles are going to get worse mileage.
http://www.edmunds.com/insideline/do/AutoshowArticles/articleId=108748
"The 9-5 BioPower can also run on any mixture of ethanol and gasoline," said Jan-Willem Vester, corporate communications manager for Saab Cars USA. If you can't find a gas station with E85 on tap, you just fill up with the regular stuff and the engine management system adjusts the timing and boost accordingly.
"Mileage is approximately 30-percent worse on ethanol," Vester concedes, "but ethanol is typically 20-30 percent less expensive [at the pump], so for customers it's budget-neutral."