Realistically, the time for nuclear (fission) has past. If we were in the 50s or 60s, and were making a concerted effort to remove fossil fuel energy production, nuclear could have helped us do it. Now, with steadily decreasing renewable energy costs and cheaper and more effective battery storage, it’s a break-even option at best, and takes a long time to implement.

Fusion has a real chance, provided we can figure it out well enough to do anything with it. It may not be economically viable, and it’s hard to be certain before we actually get it working. Fusion could also be more effective for certain space missions, especially to the gas giants and farther from the sun. Realistically, anything closer than Mars does pretty well with solar.