The original CT TLs had a solar age before fusion. So I would expect many if not most are operating on solar panels as a lower capital entry cost option.
But once Fusion is "solved", solar will vanish. Fusion (as portrayed) is far cheaper, and far more efficient. The only reason for solar is because you don't have fusion. And, given the timelines, we do have Fusion, and lots of it.
There's little reason we can't have community power centers, where each town has it's own Fusion power plant.
Apple headquarters has their own natural gas power plant to power their campus, augmented by large amounts of solar. Cheap fusion democratizes energy.
With the combination of solar and batteries, my house is, mostly, "self sufficient", generating and consuming its own power. And I live in an urban area.
A small town of 50,000 people can run their own power plant, cheaply, safely, and efficiently. Lessening the need for a grid. We have a power grid because the power plants are monolithic, large, dirty, expensive and not where the people are.
Cheap fusion fixes that.
The problem, though, is with cheap power comes more power. My solar guy said that most folks who install solar INCREASE their electricity use. "Why not? It's FREE(tm)" People turn lights off to save power, not light bulbs.
More cheap power means more cheap air conditioning and other things that create heat.
Some areas of high density in areas like India, air conditioning is becoming a problem. Urban heat bloom has been on folks radar for some time. More "free" power means more power consumed, which means more environmental heat.