A worldwide grid is absolutely possible from a technical perspective even with boring non-superconducting aluminium and/or copper, it's just that the combined cross section needs to be in the order of 3m^2, which is 17 years of current global output of both metals combined and has a current cost of a few trillion USD: https://news.ycombinator.com/item?id=32198057
(That said, my old linked estimates are over-simplified, that's a single minimal ring, and only works if the 64% resistive losses for current existing HVDC cables over that distance match the possibly lower demand because people do less at night).
Sure, I don't mean to imply it's not possible or anything even close to that, merely that it's something that will take a while rather than be ready this decade.
I'm kinda leaning towards expecting batteries (specifically batteries and not storage in general) to be the first way a continental power grid gets to 100% renewable, even though I prefer the aesthetic of a global grid. But I don't have any skin in the game, and wouldn't bet against e.g. a cheap high temperature superconductor grid or liquid hydrogen.
Batteries will always be the expensive choice of storage. There will be a certain amount of it anyway. But utilities, for bulk storage, will favor cheaper alternatives.
Perhaps it will be the expensive choice, but I expect batteries produced for cars to be moved to grid storage when any given vehicle's capacity drops below the level useful for transport, and the combined capacity of the reused batteries of a fully-electric-car-nation, even with those batteries in a worn state, will suffice for grid storage.
My guess is this transition will take 15-20 years to complete, but I have low certainty on that.
As I understand from reading Vaclav Smil's “How the World Really Works”. Replacing fossil fuels by renewables isn't simple:
"we are a fossil-fueled civilization whose technical and scientific advances, quality of life, and prosperity rest on the combustion of huge quantities of fossil carbon, and we cannot simply walk away from this critical determinant of our fortunes in a few decades, never mind years."
Of course we can. Just do the calculation into TW and then that’s how much renewables we need. We built a ridiculous world war machine in less than 10 years and then a crazy space machine in the 20 years after that. Making wind and solar is kind of easy and as you did it it would get cheaper to do (as you lowered the cost of energy to 0)
If you add in "rebuild all the transmission lines" to the cost then that would be good. Comparing some costs of renewables to total cost of nuclear is a fun pastime, but doesn't help the debate.
This seems to misunderstand the context. Previous poster was saying that with enough renewables hundreds or thousands of miles apart, there will always be enough power generation capacity.
The response was around how the newest transmission technology isn't so lossy. But that would mean we'd have to replace all transmission lines.
This doesn't apply to nuclear because it doesn't rely on generation potentially coming from 500 miles away to make it work.
To completely replace fossil fuel, you need a lot of nuclear plants and nuclear materials and transmission lines. For renewables you can handle a lot of the load near the consumption point and only need to transmit the “night load” which is usually much less.
So if we can't trust statistics provided, how are we supposed to collectively discuss and reason about the options to determine the most economical one?
wind does not always blow nor can you always deploy a turbine and you clearly don't understand the ridiculous amount of space taken by the windmills to actually over provision.
Technically if you were to over provision, yes that would work, but the problem is more that you cant even do it because of multiple different reasons. It's easier to understand when you realize that we don't have more hydro because most of the good places already have a damn. The best place for mills is currently in Denmark where they are being deployed at sea, thats not most places.
Nuclear is the way to go for base power and the voltage adjustments can be done with windmills, solar and as a last resort with a coal/gas plant.
Australia + Saudi Arabia + Utah each have enough empty land to easily provision the worlds energy requirements in solar alone. The sun is always shining on at least one of them (maybe the pacific is a bit too big, but we are talking only a couple of hours).
Denmark is not the only place the wind blows in the world. There are many windy places globally.
But I agree nuclear is another option, but it’s not the only way
If every country over provisioned renewables, then you have a transmission problem not a storage problem.
The sun does always shine, the wind does always blow.