Brazil substitutes ethanol for oil

for transport purposes.
An excellent article about an oil free transport fuel. Of course you have to look at the entire lifecycle and make sure you're not burning loads of oil/coal to make the ethanol but it amply proves the concept of replacing petrol with ethanol.
Is it as cheap? Don't know and difficult to tell with govt subsidies and such but the question isn't so much "can we make a petrol substitute as cheap as petrol?", it is "can we make a petrol substitute that is zero emmission and ball park affordable?".
I think the answer is clearly yes.