Solar and wind are not always there when you need them, so you need some source of electricity that is. Current ways to store power (batteries, pumping water uphill) are too expensive.
Those are not comparable power sources. They cannot substitute for fossil or nuclear plants, because they are way too expensive and do not provide 24/7 power without even more expensive batteries.
Actually, thermal solar plants can produce electricity 24/7 just fine. They can store heat in water or (more efficiently) molten salt up in a tower and use it to later generate power at a reliable rate.
Spain is known to be investing heavily on concentrating solar power.
Those are great they just don't generate a lot of power though. The biggest one so far peaks at 60MW while your standard nuclear or fossil power plant generates 1000MW consistently. You'd need at least 20 of these to replace just one coal plant. That makes it what, 5 times more expensive than nuclear / fossil? Not even the USA can afford to go 100% renewable with a price like that.
"That makes it what, 5 times more expensive than nuclear / fossil?"
I'm not sure that's an accurate assessment, given that solar will probably become much cheaper as more solar plants are built.
And, as we're seeing with the Fukushima and Chernobyl disasters, the real price of nuclear could be much higher than just the price of a power plant.
What would be your price tag on the lives lost in or ruined by these nuclear disasters? (not to mention the economic cost stemming from the areas being contaminated by nuclear fallout)
"Not even the USA can afford to go 100% renewable with a price like that."
Of course they could. They could start by giving fewer handouts to the rich in terms of bailouts and tax breaks. Then they could cut the military budget so that the US no longer spends more on its military than the rest of the world combined. And they could legalize drugs, and get rid of the War on Drugs, cut spending on filling prisons with people who commit victimless crimes, etc.
All together that would make for many trillions saved (plus a handy profit on taxing legal drugs). Then the US could easily afford to go 100% solar (and probably much more), without any of the risks of nuclear.
I understand that there are many political reasons why none of these things are going to happen in the US any time soon (though some estimates put legalization of pot on 10 year horizon, when the baby boomers start withdrawing from the political scene, and as the younger generation is far less afraid of pot). But it's not like these things couldn't happen.
It's all a matter of political will.
If there's one good thing that's come out of this latest nuclear disaster is that it's starting to wake people up to the true dangers and costs of nuclear power. Hopefully they won't need many more such lessons before they get the point.
