Re: Wind and solar
There is probably a good reason to scram a reactor when the most powerful earthquake ever recorded in Japan strikes just 100 miles away.
The acceleration of the ground at those sites exceeded half a g, which is 20% more than the design spec called for. Note that they are built on rock, sedimentary acceleration a few miles north was over 2g.
This alone destroyed the 6 primary external generators.
The tsunami that earthquake generated was 15m high at the plant.
The design of defenses was protecting against a 3m tsumami (based on the 1960 Chile tsumani), though that was revised to ~6m in 2002. They were in discussions about potentially higher tsunami, but little action had been taken.
Yes, they should have done more to protect against seawater ingress into the building (which killed the batteries and the backup generators). Either by moving the generators up the hill, or upstairs in the buildings.
But that's all the generators, batteries and switch gear that would have needed moving. Not exactly an overnight job.
The evacuation was ordered based on a level a little under 3 times the background in cornwall.
The background level before the tsunami was about 10% of that in cornwall.
The numbers were, and are, pretty small, and the risks are also fairly small - the biggest risk was always the massive bloody earthquake and tsunami. The Iodine and Caesium (particularly 137) is not something we want to be releasing... but the alternative is the last decade of burning fossil fuels - since they have ~25% coal still we can reasonably assume that the coal is what hasn't been displaced by nuclear generation.
Before the tsunami a third of it's electricity came from nuclear plants, it's now just 5%.
So... Japan uses ~1 PWh/year, so 250TWh of coal per year, for a decade... that's 2.5PWh, at a reasonable estimate of 25 deaths/TWh... that's 60+ thousand deaths as a result of using coal rather than nuclear generation.
Was the initial evacuation overkill?
I'd rather evacuate safely and unnecessarily occasionally than not.
But the evacuation itself caused serious issues as well.
The limits places on background doses were pretty strict - again I'd rather start strict and loosen after consideration.
Was the decision to cut back on all new builds and all existing nuclear generation for a decade overkill - absolutely.