[wait_a_minute]

Getting only 1,000 times more than humans are using now but requiring 50% of the earth's surface seems like an awful deal. Not only do you need much more of the earth's surface, taking away from trees and habitats and other uses, but you need to significantly increase mining activities to produce the panels and their associated infrastructure. Whereas to get 15,000 additional terawawtts from more nuclear reactors, you could do that with 1,200 - 1,900 additional nuclear reactors occupying just the size of Rhode Island.

[kragen]

mostly you'd be floating them on the oceans (ideally the currently-nutrient-depleted parts of the oceans that aren't teeming with algae), but yeah, that's roughly the limit for solar, and as you're approaching that limit, you need to be thinking about space-based solar power, nuclear power, geothermal power, etc. maybe when you're at 64× of current energy consumption, say

since 02000, total solar installed capacity has gone from a gigawatt to 1.6 terawatts (see https://www.ise.fraunhofer.de/content/dam/ise/de/documents/p... and https://en.wikipedia.org/wiki/Swanson%27s_law#/media/File:19...), which is roughly 10 doublings, one doubling every 2.3 years. but that's peak capacity, and 1.6 terawatts peak is only 220 gigawatts of actual production at a presumed capacity factor of 21% (see https://en.wikipedia.org/wiki/Solar_power_by_country). that's 6 doublings away from world marketed energy consumption; adding the other 6 doublings to get to 64× gives you 12 doublings, and thus about 28 years before this starts to be a concern

probably we should think of this as a lower bound, though; adoption is likely to slow down as solar moves into application areas that are not already electrified or indeed yet done at all by humans, and the last 24 years have been, historically speaking, unusually peaceful

[bryanlarsen]

But we wouldn't need 50%, we'd need .05%

[wait_a_minute]

That depends on how much more efficient solar panels get and what future energy requirements are, but in any case it'll be worse to scale energy creation with solar than with nuclear.

[bryanlarsen]

We'll never substantially increase our energy demand if we don't reduce our energy cost. And since nuclear is horrendously expensive, it won't scale.

[kragen]

i would instead say that as long as nuclear energy is horrendously expensive, it won't scale. but nuclear energy is not inherently horrendously expensive; it's just that human technology is very primitive still