How many batteries do we need to store the equivalent energy in 1kg of uranium or thorium? And how much mining is required obtain those materials and how much energy is required to refine those chemicals or elements? And repeat for the millions of solar panels and wind turbines. And shipping them around the world in diesel powered boats?
> How many batteries do we need to store the equivalent energy in 1kg of uranium
Energy density isn't, alone, determinant here.
The most determinant question is: after taking into account all measures aiming at reducing renewables' production 'intermittency' ('variability' is more adequate), which are: spreading a mix (wind, solar, geothermic...) of renewable sources on a continent, enhancing grid interconnections among nations for them so support each other (objective already very actively and more and more pursued in Europe), storing at continental-level renewables' over-productions (thanks to hydro, hydrogen...) and using it on a clean 'backup' compensating for renewables' 'intermittency', demand response...
... then how much energy do we need to store in order to compensate for any remaining 'intermittency'?
Given that the average electric car battery can power the average home for quite a while (days), and that other EV batteries will be online...
Moreover each year 7% to 10% of gridpower is in France (fully nuclearized) produced thanks to fossil fuel, and its electricity is low-emitting, giving a quite comfy last-resort.
> And how much mining is required obtain those materials
Those materials are recyclable and have substitutes.
Uranium isn't (in practice) recyclable and doesn't have any substitute: this is eternal mining of an ever-rarefied source.
> shipping them around the world in diesel powered boats?
This is a valid point, enforcing the need for each continent hosting cooperating nations to produce its own production units.
On the other hand uranium reserves at current conditions can provide for at best 200 years (more probably 130 years: https://en.wikipedia.org/wiki/Peak_uranium ), therefore the conditions (price and emissions, as the raise as the ore grade lowers may quickly worsen if some 'nuclear renaissance' stems reactors building projects. Who will take the risk and invest?
The architecture I described does not imply that those batteries will be loaded by locally-installed solar panels. There will be a grid, as usual, carrying electricity produced by the described mix, mostly by industrial sites (in many geographical areas a large part of it will be offshore wind turbines fleets).
No: they are benefiting from it as they (most of the time) load their batteries when electricity is cheap, and discharge it into the grid when it is rare and therefore expensive.
On average the car autonomy already is way above the daily commute, and this margin is quickly growing.
There are more and more parking places (private and public) connected to the grid.
> No: they are benefiting from it as they (most of the time) load their batteries when electricity is cheap, and discharge it into the grid when it is rare and therefore expensive.
This would only work if the added charge on night-time electricity also accounts for battery cycling cost which I doubt it would.
Very low or even negative prices, during episodes of renewables overproduction (typically when wind blows or sun shines way over demand), are more and more common.
Reciprocally as more and more less tolerated grid backup (greenhouse-gas emitting fossils or dangerous nuclear) disappear episodes of under-production will be more common, and during those electricity price will soar.
It's not as much mining as you'd think -- it's not comparable to nuclear, sure, but I was surprised to learn, for example, the enormous difference between a fully decarbonized future vs. carbon present in terms of mining / extraction volume.
