Petrol will not just run out, it will however slowly increase in price as people become more concerned with it.
There are plenty of options, LPG, propane, methanol, coal dust, electric, hydrogen, hybrid, biodiesel etc..
I think ford Australia would be wise to invest in a Diesel power plant. It makes alot of sense.
One of my crazy predictions is external combustion will come back into fashion because of its emissions potential, flexability of fuel source, economy etc. But governments would hate it because they can't tax the crap out of its fuel system.
more than 50% of the petrol price is tax. This will increase to 60-70% over the next decade.
Ford would be well placed in the market with Diesel and LPG falcon varients tho.