We have less than 100 years of uranium assuming we use enriched uranium once, don't reprocess the "spent" fuel, don't use breeder reactors to make plutonium for further energy production (going from 100 to thousands of years at current usage rates), and don't use breeder reactors to produce U233 from thorium, which is so much more abundant and available than uranium that it would extend current use by another 100-270 times, meaning current usage at hundreds of thousands of years, with already known deposits of nuclear fuel. These aren't breakthrough technologies, but just engineering, because we already know how to do this. Electricity was forecast in the 1950s to be too cheap to meter within a few decades of building reactors, and that future was completely practical. We just chose (at least temporary) stagnation, instead.
Solar is definitely cheaper than current nuclear, and continuing to fall rapidly, while battery cost is also improving apace. In the short term, solar can meet most of our needs and let us turn off more coal and oil, and that's certainly useful! In the medium term, though, we can't get back on the Henry Adams curve without denser sources than sunlight, which takes up quite a bit of real estate even if we move most capture to space.
I don't know how you can say with a straight face that solar power is a stopgap and nuclear power is a long-term sustainable solution. I cannot rightly comprehend the confusion of ideas that would provoke such a statement.
Well, I said “medium” term. But ultimately if we stayed on the curve (that is, longer term), humanity would be using the entire output of the sun in less than 2000 years, requiring a Dyson sphere or something. Solar power can’t keep up with human flourishing. We’ll have to have something that is denser and more distributed. :)
I feel like we're talking past each other. If we are to get back on a steady growth rate in energy/person, solar on earth is a great short-term part of that, fission is required for continuing it in the medium term until we figure out something else (fusion, but then whatever we might unlock down the road).
You're globalizing what I said about having enough uranium and thorium in known deposits and at current power usage, but obviously we would outgrow that as we expand into the rest of the solar system.
My point is not that we should stop or slow investment in solar (we shouldn't!), just that we'd all have been much, much better off if nuclear had continued to be adopted at speed in the last 50-60 years rather than being demonized, and for high density or unlit areas, it's still a great option and has no risk of running out of available fuel in the next hundred years.
We don't have to assume infinite growth. We can reach a comfortable sustainable point. We're already living in a pretty comfortable future (but it's not equally distributed). But if you do assume infinite growth and worry about the long term, then why stop at a Dyson sphere? What happens when every single human being wants more power than exists in the observable universe?
We've actually seen a decline in energy-per-utility ratios. We've got a lot more people and (apparently) a lot more utility per person, so we're still using more energy in total, but if we held those constant for the past several decades we'd actually be using a lot less energy per person and in total. It's not at all inevitable that energy/person/time only goes up. The Jevons paradox eventually maxxes out - if we could teleport anywhere instantly for free, we'd still only be making a finite number of teleportation trips each day. The crew of the Enterprise replicate a finite amount of food, and so on.
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Possibly, nuclear could have been a better intermediate energy source for the past 50-60 years than the fossil fuels we did use. In countries that did adopt nuclear energy (like France) it did seem to work out that way.
Now, in the present, which is when we are making decisions, it's time to go all in on renewables (and long-term infrastructure, much more generally). This brings some challenges, but not insurmountable ones. We'll probably need more load shifting, more cross-border power trading, and more batteries. (Hydropower is also renewable and works at all times of day, but it's not available in all locations, which brings us back to cross-border trading).
I don't see why you'd need nuclear power for high-density areas, or "unlit areas". High-density areas are full of all sorts of stuff, including power cables which can import power from the surrounding countryside - there is absolutely no need to build a fleet of nuclear reactors in the middle of New York City. Even with the substantially-lower-than-Chernobyl risk levels assumed by nuclear proponents, I think the idea of building a fleet of them in the middle of NYC should still be concerning to them. And for "unlit areas" - I assume this means extremely rural villages or whatever - you know a medium-size solar farm, a couple of wind turbines, or even a small diesel plant, takes a shitload less maintenance than a nuclear reactor, right? You're not importing nuclear technicians to permanently work in the middle of the Sahara or the Amazon - you're either connecting them to the grid properly, or you're giving them something set-and-forget that can hum away in the corner for years on end.
Big batteries coupled to diesel generators will remain a great local backup source for critical systems for the foreseeable future - if I was world dictator, I wouldn't ban them outright. Somewhat interestingly, the opposite is already also true: battery-buffered solar power is used in remote sites where you might expect to need the reliability a diesel generator, because a small chance of the thing being down outweighs having to keep it refueled.
Solar is definitely cheaper than current nuclear, and continuing to fall rapidly, while battery cost is also improving apace. In the short term, solar can meet most of our needs and let us turn off more coal and oil, and that's certainly useful! In the medium term, though, we can't get back on the Henry Adams curve without denser sources than sunlight, which takes up quite a bit of real estate even if we move most capture to space.