Prohibition didn't start until 1920. We had quite a few refineries and gasoline stations providing the fuel for cars then. Ethanol "refineries" were not producing much of anything beyond medicinal and drinking.
It would be interesting to know if the sequence was:
1) Alcohol-run Model T built.
2) Prohibition.
3) Model T forced to switch to gasoline.
That was the writer’s contention. I’m not familiar enough with early 20th century history to confirm, or refute that.
If that was the sequence, it is interesting.