[sigh] We didn't start using oil because of peak coal. There is reason to believe that the transition from oil will be based on the development of a new, superior technology rather than depletion of oil reserves. It's not a ceiling we will "bump" against. Marginal utility means that other technologies will slowly come on line and increase in use as the price of oil rises.  This will more likely be an orderly transition that a disruptive, abrupt change.

Not to say there isn't substantial risk of disorderly, abrupt change- just that it is likely to have little to do with oil.