I spell out my conjectures.

Scenario Most Economical Timeframe Remarks
Carbon Competition 2008-2020

Cheapest energy sources, except for political barriers
Conservation 2008-2015 Smarter electric grid, better car batteries
Nu-cu-lar 2013-2030 It works, but at what risk?
Franken-fuels 2020 and beyond The most likely revolution
Solar Singularity 2025 and beyond Hope it happens