From Wikipedia:

According to Ford Motor, the Model T had fuel economy on the order of 13 to 21 mpg (5 to 9 kilometres per litre or 11.1 to 18.7 litres per 100 km). The engine was capable of running on gasoline or ethanol, though the decreasing cost of gasoline and the later introduction of Prohibition in the United States made ethanol an impractical fuel.

How little things change... from fuel mileage standards to boneheaded decisions about green fuels