Solar is never gonna be a complete solution. At the end of the day, we could do it more efficiently by just building suns here on earth for the panels, but of course then you've achieved fusion and you're already generating more than solar could ever hope to. We shouldn't hinge our future on half of a technology.
My larger point is that solar is only ever going to be a piece of the puzzle at best. In space it might be quite nice, but otherwise it's kinda goofy to invest too much in.
Doesn’t that apply to any power source?
Stars don't have this problem because they're very large so there's only so far neutrons can go.
1. Stars do it. Yes. But stars also have size and gravity, something no nuclear plant will ever have; and
2. "People once said X was impossible" ie the Galileo Gambit. Just because Galileo was mocked for his heliocentric model but was later proven right does not mean everything is possible.
Thing is, I'm not even talking about physics. I'm talking about engineering. Something not only has to be possible but it has to be technically viable and sufficiently cheap. Put it this way: would you pay $60 billion for a 1GW power reactor with a lifespan of 30 years and an annual maintenance cost of $2B? Even if the fuel was completely free the wholesale cost per MWh would be ~$600. Nobody would build that.
Fusion research has been going on for decades and the best we've done thus far is fire a laser for about a second to induce a fusion reaction and also spend billions building magnets to try and contain a turbulent fluid at 100 million degrees, which, again, will do nothing about the neutrons that will destroy that vessel.
The joke is that fusion is always 50 years away and always will be. If you're an optimist it's always 30 years away and always will be.