A question from Yahoo! Answers:
Is an oil free economy achievable?
Yes, but not cheaply. Power stations and heaters designed to burn oil will have to be converted to natural gas or coal or replaced. Share of electricity generated by nuclear power plants can be increased as well (with all additional risks it brings). Gasoline can be made from coal or natural gas as well, but at the present level of technology, it will cost north of $3 at the pump regardless of oil price (the bulk of the cost will be processing).
One area where oil will be very difficult to replace is rubber and plastics…