1. That's kinda obvious, in theory.
It seems this entire discussion is theoretical.
And taken in isolation without expanding the thinking about consequential changes so induced.
Not sure what you mean. But if you're suggesting that there are downsides to nuclear, well, that's kinda obvious too. As the title of the thread suggests, there is no free lunch.
2. Oil will never be worth nothing; for a start, we depend on plastics for an enormous volume of products and machinery still requires lubrication. As for Saudi, that's a political point and also flawed from the point of view of its influence: it's money will not simply evaporate, and money is influence even within a domestic family. And let's not even touch on the religious impact it has worldwide.
Of course it won't be worth nothing. Forgive the slight hyperbole. The point being that it will be unlikely that the western world would be dependent on imported oil for the uses you describe, particularly from the core of middle eastern nations that are all inherently unstable; those who enjoy stability receive it from without and not within, solely due to the value of their oil. Those who once enjoyed stability from within, Iraq, 'enjoyed' it at the cost of brutal suppression. Money does not evaporate. But it might as well. Witness the mark following WWI. Plenty of them; no value. Saudi Arabia produces nothing more than oil. The population, while educated, is virtually without a skilled labor force. They are almost entirely dependent on imports. Without oil they have nothing to export except terrorism. So yes, of course this is a political point but there can be no discussion of the future of energy production, global climate change and pollution without a geopolitical discussion. Simply fruitless. And I'm glad to refrain from discussing the impact of religion, but it is also tightly intertwined in the discussion of oil and politics. It cannot be separated. But it can be mitigated when the middle east is no longer the arbiter of western energy resources and economic considerations. Then the discussion can simply be political or religious.