(Yes, of course we need to have electricity in hospitals and for heating 100% of the time - but if the newspapers are unavailable three days per year, or if some non-essential TV channels turn off when it's really cold - maybe not as bad.)
Natural gas is currently the peaker plant solution to renewables. The fact that more of these plants exist is primarily driven by the fact that larger portions of the grid are being pushed towards renewables.
A little bit of nuclear in the mix, plus storing biogas, and aggressively pursuing thermal solar is very important, IMO. It just isn't possible to overprovision wind enough to meet 99th percentile supply/demand mismatch, but having a few percent of nuclear base load really helps.
If we want people to stop burning natural gas and heating oil for their homes, and more to move to electric cars, we'll need a ton more base load, too.
Yes, nuclear can't compete with natural gas base load, but we want to stop burning so much natural gas, so...
Even with a pure nuclear grid, you'd still need a peaking source. That would be provided, probably, by natural gas or hydro if available.
A storage solution is simply required regardless of where the grid goes. I think that Liquid metal batteries look to be the best solution for grid level storage. (relatively cheap, super long life, if massively adopted would likely become a lot cheaper).
If everyone does it, then there would be no place to export excess, what do you do then?
