The goal is very noble and I'm all for it, but there is this problem that the sun doesn't always shine and the wind doesn't always blow, and electricity isn't infinitely transportable, nor easily stored.
One interesting idea I've heard in regards to storing electricity is using electric cars as batteries. Granted, this would require a massive retooling of our grid and our transportation system -- not to mention the question of where we will find all the resources to make so many batteries -- but it's still interesting.
What's troubling to me is all the sensationalism surrounding nuclear, which seems to suffer from lots of near-religious objections. Nuclear is dangerous but even in the worst scenarios (like the Fukushima Daiichi plant) the damage is far less onerous than the continued operation of coal plants.
http://www.fastcompany.com/1708167/how-to-make-lithium-batte...
Discussion:
http://news.ycombinator.com/item?id=1986640
Summary: Infusing Li-based batteries with the Tobacco Mosaic virus could boost their storage capacity up to 10x. There's one order of magnitude...
They had to have rotating power outages for a week or two in Japan after the earthquake because of the need to replenish those reserves.
Requiring 100% replacement/utility is not a useful position. If we want to reduce (notice I didn't say eliminate) use of fossil fuels, then we have to pursue a mix (including fossil fuels).
Edit: You didn't actually require 100%, but this edit is an easier correction than a correction.
"If" that is true, then a time-shifting bank of such supercapacitors could presumably solve the very real issues you raise.
Wind or solar solutions that he specifies have to be rugged and easily maintained without access to fancy tools, and batteries can wear out quickly in high-temperature environments.
Thus he has been researching supercapacitors.
The other no-storage option is to retain water at hydro facilities during the day and use more at night to balance the solar production.
That gives us plenty of time to see if the liquid metal battery will work out, or to start building reservoir pairs.