To be fair, neither nuclear power nor sun or wind are anywhere near their full potential.
Nuclear: What I've read suggests that nobody is seriously bringing back the the power plants of the 70's. IIRC what's suggested are small plants that new technology allows to be much less dependent on meticulous maintenance. IIRC most of the problems with nuclear power plants were caused by or at least abetted by human error.
Wind: As much as it appeals to me me, there're limited locations where it can be used. Expanding out of the usual locations incurs increased costs that may affect its economic viability. That said, there's still plenty of room for more windmills.
Solar: The efficiency of photo electric cells has been has been creeping up while costs have been slowly falling. Places where solar cells weren't economically viable 20 years ago are now. Given the state of battery technology, I suspect there'll be slowly growing % of homes with solar panels that sell excess back to the power plant when the sun's out and drawing from the grid when domestic demand is greater than supply. I've not come across any reason to think this slow expansion will stop.
Batteries: Cost, speed of recharge, energy density, and longevity seem to be at the corners of a figurative square. If you move toward one, you move away from at least one of the others. But here's another place where technology seems to be slowly improving. As for vehicles, people's 'range anxiety' is founded upon external realities. Focusing on the people fails to address the issue. Plug-in hybrids will be more and more common. OK, off cars.... I'm drifting off topic.....
However, dependency on fossil fuels is slowly becoming a less viable option due to pesky things like climate change, pollution, and.... oh yeah, depletion. The result is that we have to do SOMEthing whether we want to or not.
Of course, alcohol would be a more viable option were we to try getting it from something other than corn, which I've read is one of the least efficient plants to grow if your crop is alcohol. I know there're problems with using it as a fuel, but Brazil seems to do rather well with it.
I don't see any of these as a magic bullet that will replace fossil fuels overnight. What I DO see is coal, oil, & natural gas (in that order) comprising a slowly shrinking % of total energy production and the sources mentioned above grow correspondingly slowly.