Modular reactors are the only real answer.
Wind and solar alone are never going to cut it, even for just the current supply. Until we crack fusion the only answer is to use current nuclear technology to supply needs and replace fossil fuels.
Current big reactor designs and deployment are not really desirable and still have distribution problems. Modular reactors similar to those used by the nuclear subs and warships could a viable option. Placed close to where the power is needed, at end of life the whole unit is removed and sent for decommissioning and a new unit dropped into place. Benefit of many small units is they can back each other up via the grid more effectively than just a few big ones.
Waste will still be a problem but we may have no option but to store it safely until technology catches up.