The problem with the solar in the desert is the water and transmission costs. The wind also presents much of the same transmission cost issues. The people who need power tend not to live in the type of places where solar and wind work well.

In my mind, the only long-term solution will be Nuclear but that will not happen while the "no growth" environmentalists have sway. I do think that oil and NG will have long term rolls to play for generations to come as will solar and wind, but each will fit niche needs.