Virate said:
If we did run out of oil...it would be a world that has NOTHING on the World of Darkness.
If you were wondering what would happen if the oil supply suddenly ran out...
First the electrical power would start to falter, power grids would get overloaded when generators went offline leading to huge blackouts.
Actually, very little power is generated from oil in the US or EU. It is used for lubrication on generators, but you can use bio-based lubricants for that. There is plenty of coal, and since the postulated scenario doesn't have coal vanishing, we'll keep using that (belching out mercury, natural radioactive compounds, sulfur dioxide, and carbon dioxide). That should last several centuries.
Oil *is* the dominant transportation fuel, but you can also use the coal to produce synthetic fuels such as Fischer-Tropsch diesel. That is costly, but at a high enough price for oil it's worth doing. Renewable fuels also work: biodiesel costs around $2.50/gallon in the US, and cellulose-based ethanol is close to that. High, but not civilization-destroying.
Virate said:
Solar/Wind power simply doesn't generate enough energy to keep up with demand.
Hydrogen power is great, if we had a source of hydrogen that would last any length of time...we don't.
Solar and wind could *certainly* generate enough power for the entire world if we had the impetus to develop it. Cost is the only major obstacle - the resource is big enough. If coal becomes scarce (not in this century) or if global climate change becomes a real concern (more likely), it's worth the cost. You might use pumped hydropower more for storage to level out the intermittency of the renewables - when there is more wind power than needed, pump the water up into the reservoir. When there isn't, let the water flow. (You could also use batteries on a large scale - if they're stationary, it doesn't matter how heavy they are.)
Hydrogen is an energy carrier just like electricity is. It's not an energy source. You could use electricity (from coal, solar, wind, nuke, hydro) either to split water into H2 and O2 or you could store it directly in batteries. Which one we use in vehicles depends in large part on which storage technology is better-developed.
The point is, we have a lot of great options in renewable fuels and electricity that we just aren't using now because fossil fuels are cheaper. So if we ran out of both coal and oil then energy (electricity and vehicle fuels) would cost a bit more - perhaps twice what we pay now, given the learning curves you would see. That's something we can adapt to. Once demand exceeds supply and supply cannot be increased fast enough (not the same as running out) there will be a shock for a few years as the price of oil skyrockets. But, assuming that we are smart enough to realize our options and avoid an apocalyptic war for oil (a la Mad Max), then we'll bring alternatives online and adjust. Life will go on much as we know it, except for some geopolitical changes (probably the fall of the House of Saud).