My biggest question about what will happen if we had 20% or more of solar/wind power is what do you do when the wind isn't blowing and it is night time? You are still going to need as much traditional generating power as we have now but it will have to sit idle while the "free" stuff is working but be ready to fire up at a moment's notice when a big cloud comes over or when the wind dies down. That is going to be an expensive plant to maintain and not as much revenue to maintain it. The thing that sets the US apart from the 3d world is the reliability of our power infrastructure and I think that will go away.
I really believe when they feathered the windmill in Minot it was to deal with a drop in demand.
The economics are key. Honestly, if our wind and solar resources are spread out, there is very little chance we will lose *all* our wind and solar simultanously. And certainly not very quickly, at least outside of a solar eclispe, and even then, the total occlusion is usually limited to a small area and certainly predictible.
But we still need extra plant capacity, and that's highly expensive infrastructure, just sitting there wasted and unused. Pocos make more money running at 100% with 1% rolling brownouts than that do at 99%; it's like the airlines with that respect; no incentive to add planes or plants if they're not going to be utilized eto 100%. So, we end up with a situatiotn like Texas where the only other source of power were emergency stand-by generators that people have to invest in anyhow.
...which, actually, has never been brought up in a solar/wind debate that I'm aware of, but IS a great untapped source of power generation- there's no spool-up time required like there is to build up pressure at a steam turbine plant, 10 seconds after the brownout hits the preset on the ATS, that plant is up on generator. If 20% of the US has their own generators and has to run them 1 day a year because of a freak mass solar/wind outage, that's OK. The pocos give them a price break for doing something they'd do anyhow (go to generator during a brownout), coal and gas consumption is reduced considerably from all the "free" energy, and everyone wins.
Still, anyone who thinks wind and solar can become more than a niche in american power is dreaming. What we reallly need are more nuclear plants.
