Earlier quoted context omitted.
Nuclear plants are also "intermittent" - the average US reactor spends 32 days offline per year. Does that mean a grid relying heavily on nuclear needs massive amounts of storage? No - it means you need to have redundant capacity which is the solution also used for wind and solar. The benefit of nuclear in this regard isn't that it's "non-intermittent" - it's that the most common failure modes for a nuclear nuclear a…
A capacity factor of over 90% is exceptionally good. Wind and solar are 35% and 25% respectively [1]. And this down time for refuelling and other tasks is scheduled in advance. This not at all comparable to solar and wind's uncontrollable intermittency. A nuclear grid requires vastly less overproduction than a renewable grid. As you point out, renewable sources end up falling back on fossil fuels to pick up the slack…
Storage and distribution works the same as for fossil methane (pressurized in cave systems/old gas wells).
Production is simple, and we yes, the efficiency is around 20-30% round-trip. But that's enough to handle up to ~30% of electricity supply with less than 2x overcapacity.
And that's assuming you don't just slap carbon capture on a gas turbine you feed with fractionally distilled oxygen (>99% should be easily enough) and enough exhaust back-feed to not melt the turbine blades. A diesel would probably deal better with the combustion temperatures, though.
And Fischer–Tropsch can turn captured carbon into piston-engine-suitable liquid fuel, if you'd need to.