> grid infrastructure that has reach across timezones,

"Night" reaches across more time-zones than you can build your grid across.

Never mind "winter".

> nuclear powerstations are not as reliable as you might think - they often go offline.

Define "often".

They are actually a lot more reliably than you seem to think: the capacity factor of the US fleet, for example, was >90% for the last decade(s). And that <10% offline time includes the planned refueling/inspection/maintenance times.

Nuclear power plants are incredibly reliable.

> Night" reaches across more time-zones than you can build your grid across. > Never mind "winter".

Demand isn't at an even level across the night ( high early evening, low 3 am ) - if your grid spans time-zones you can smooth that out, and renewables span more than solar. Wind doesn't stop at night, hydro doesn't stop at night etc.

> nuclear powerstations are not as reliable as you might think - they often go offline.

Maybe it's a UK thing with nuclear reactors operating beyond their initial design life - but there was a situtation last year where the majority of them were down at the same time and the UK had to make high use of our interconnect with france ( using their nuclear capacity ). In the UK the 2025 nuclear output was 12% down on the previous year due to outages.

The point here is that a grid that expands beyond national boundaries - helps in general, not just specifically for renewables. And before you go on about energy sovereignty - where do you think the Uranium comes from?

I'm really not impressed with this reoccurring argument: "Solar power is good." "But night!"