The alternate fuel sources don't look too hot right now. I thought hydrogen would be a good one, but compressed gas doesn't seem to be a viable storage method for this fuel. The best and cheapest design at this point uses (You guessed it!) hydrocarbon fossil fuels. Perhaps it will be a way to use otherwise unsuitable petroleum products for fuel, but I don't think it's the answer.

Methane might be a suitable replacement for natual gas. Vehicles are the main concern though. Methane might be able to power vehicles, but the tanks are dangerous and big. OK for personal vehicles, not so good for trucks.

Alcohol takes too much energy to distill to really be cost effective. It's also very corrosive and sensitive to humidity. It forms a solution with water.

Electric is a GREAT alternative. We have plenty of technology and experience using it. There are many sources of energy that will produce electricity cost effectively. Everything from Hydroelectric, Solar panels, geo-thermal, atomic, etc. If only we had a good way to store electrical charges. Our electric infrastucture is currently "on-demand" type generation/ It's produced as it's used and the devices using it are tethered by wires. Can you imagine the ability to capture lightning strikes and store even a small portion of the energy? Unfortunately, the most cost effective way to store energy is still the old lead acid battery from years ago. Railway's may be able to use electric right now, but individual automobiles are a different matter. Battery replacement will have significant hazardous waste also. Effective recycling would be key to this working.

Also, A LOT of products we use come from petroleum. Plastics, fertilizers, solvents, paints, etc. We would have to learn to synthesize these from some other raw materials.

Basically, at this point petroleum is the life blood of our modern civilization. I'm fearful of whether we can truly live without it.