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ok so, minor addition here.
Both ac and HVDC are relatively efficient forms of power transfer.
The problem with AC is the skin effect (tl;dr is that the current is carried around the edge of the conductor, not the center, though you can cheat this as well) And the fact that AC running in a submarine cable is going to essentially act as a capacitor, and cause problems. (large losses)
AC traveling through the air doesn't have this problem. The skin effect is less pronounced than you think because you can just use a higher voltage since it requires less current (transformers also have really good efficiencies when not saturated or undergoing other shenanigans) Also you can design the cabling to abuse this, using outer strand conductors, and then an inner structural strand, to strengthen the line.
HVDC is particularly applicable in undersea cables, due to the capacitor thing just not existing. Making it actually viable. It's applicable above ground, but the problem is transforming between AC to HVDC and then back to AC. There are reasons to do this, for instance you may be between two grids with two different frequencies, this is the only solution in that case. You may want the grids to be able to operate semi independently (again frequency related)
The big problem with HVDC is that it's inevitably more complicated. Prior to micro electronics we would use vacuum tubes, or prior to that, two motors linked end to end, one run on AC the other generating DC, and then duplicate that in reverse on the other side (that was also how we used to do voltage conversion in DC systems IIRC)
These days we just use semiconductors, but carrying a lot of power is hard, and expensive. (and also not perfectly efficient) There's a reason massive boxes of copper wire and mineral oil are the standard solution. Dead simple, easy to maintain, and they quite literally just work.
Thanks for the info, interesting!
I heard about a plan to use HVDC to move solar power from Morocco all the way to the UK.
https://www.wired.co.uk/article/the-uks-wild-plan-to-use-a-giant-cable-to-catch-sun-from-the-sahara
If that's feasible then moving solar power from Arizona to Minnesota or wind from North Dakota to New York seems feasible. One criticism of renewables is that the sun doesn't always shine and the wind doesn't always blow but it's always sunny and windy somewhere and we can move that electricity around with HVDC, lessening the need for storage.
this is true. But the technicalities present are immense and would require some significant mathematical modelling in order to optimally determine the solution.
The primary issue with long distance transmission is that unless it's one singular line, it's really difficult to know where power is going. It's realistically going to take the path of least resistance, but what this path is, where it is, and where it goes is complicated. If you have a long distance transmission line from point A to point B it's much much simpler and a lot easier to deal with.
A particular example would be alaska, particularly farther north, where the sun gets really bizarre in the winter. That's a prime candidate for anything that isn't solar basically. Wind might even be problematic with the temperatures there. Nuclear however? Great starting point.
It's hard to phrase it, but basically. hyper local generation is going to be more important than long distance transmission with renewables, particularly wind, it's just more efficient that way. Even if norther solar panels produce less power than more southern panels, it might actually make sense to have them there, due to transmission complexities, losses, and just general shenanigans. (if one significant transmission line goes down an entire grid can fail)
If you were to just plonk down a plant in arizona for instance, and hook it up to the local grid. That power is going places. Where exactly? Nobody knows! It could be literally anywhere within the grid! Heres a particularly good demo of this
You could very well export lots of solar and wind, but honestly, i think it's just going to be more feasible to properly manufacture nuclear power, until we can get fusion power to be a thing that exists. It's stable, flexible, and we know it'll work. As anybody would in CS would tell you, it's a heuristics problem, and heuristics suck. They're relatively accurate, and give good information, but they are a pain in the ass to develop. Though i guess if solar manages to do that for cheaper it just doesnt matter lol.
(also in case you're wondering, they're using HVDC cuz it's undersea transmission. They might also run at different frequencies? I dont know.)
We're in desperate need of an upgraded grid anyway, that's a separate issue from nuclear. It needs to be able to carry power over long distances, incorporate local generation and intelligently route power to where it's needed. It also needs to be robust enough to keep hackers out.
Even though it's a separate issue, if we build that then nuclear makes even less sense.
i suppose so. That's another heuristics nightmare though. That or it will take centuries lol.
Also intelligently routing power technically already happens, just based on the nature of the network. I suppose certain automated segmentations could help though. Realistically if we want a fully decentralized grid network it needs to be on a town/city basis, rather than a county/state basis.