There will not be a single answer, just like there isn’t one now. I don’t think we will ever have any source as universal as fossil fuels either. But I do think we need to focus on renewables to cover as much of the energy needs as possible. A couple of European countries have done some amazing things generating near self sufficiency from renewables.
Okay, I should stay on topic too. The good news about these questions is that they need solving, and this shift is going to create a lot more jobs, which I think we all want.