Although technological progress can alter the relative costs of different energy sources, depletion inevitably must raise the costs of fossil fuels leading to their displacement by alternative energy sources. (judithcurry.com)
Given the time frame, it's more likely that we'll be using a combination of different energy sources until we can wean ourselves off fossil fuels completely. (scienceagogo.com)
This is a simple and physically sensible way to look at the climate effects of different energy system transitions. (thinkprogress.org)