[johncolanduoni]

It’s only a defect if you try to make the grid 100% nuclear, just like solar’s variation is only a defect if you try to go 100% solar. It’s not a competition where either is likely to “win”, they’re just two different tools for power generation.

[bryanlarsen]

It wouldn't be a defect if it was complementary to solar. But it's the same defect as solar/wind, so it is a defect.

[johncolanduoni]

How is it the same defect? Nuclear plants can run all the time and have to if they have any hope of recouping investment. Solar can’t run all the time but is super cheap so it doesn’t have to. You still need responsive capacity but even if you keep natural gas around for that you’ve made a massive dent in fossil fuel usage - bigger than solar or nuclear could do without the other.

[bryanlarsen]

Both nuclear & solar produce power at times when it's not wanted. Same defect.

If you were building a grid from scratch in a typical American region, and you were aiming for lowest cost, you'd overbuild solar enough that it handles 100% of demand on a sunny evening, add enough wind to handle 100% of demand on a dark + windy evening, then add about 3 days of battery storage. That'll supply you over 95% of your energy needs.

But that's not 95% of the power, it's 100% of the power 95% of the time. So you also need to supply 100% of the power 5% of the time somehow else. That's not 100% of peak, since peak is during air conditioning demand when solar works, but 100% of almost peak.

The cheapest way to do that is low efficiency single cycle natgas. CCS natgas is 1/20th the cost of nuclear, and single cycle is about half the cost of CCS.

So if you make 2.5% of that nuclear, you've doubled the cost. And you've saved a few hours worth of carbon emission, 2.5% of 5%.

If you want to be carbon-neutral, you use syngas instead of natgas. Yes, syngas is 6X as expensive, but fuel is not the main cost of a peaker plant running <= 5% of the time.