What is better? Hydrogen and Hydroelectric might be cheaper in the short term, nuke plants are very expensive. Most countries can't get nuke plants either even if they can afford them, you can't sell it to them like you can with hydrogen.

Yes. Renewables with no storage can cover 30-50% of world energy (not just electricity). Nuclear tops out at around 5% if we go all in now at around the same total cost. Storage technologies exist for the rest at about the cost of nuclear (but with actual ability to scale), but are not necessary en masse yet and are likely to drop in price by the time they are.

Going to rehash debates that we've been having for many years, but the short answer is yes.

Existing renewable tech + storage will do the job just fine in most of the world, and at lower cost than nuclear.