[myrmidon]

Completely agree with the outlook ("fusion power irrelevant for climate change in every realistic scenario").

But where did you take those grid cost numbers from? Iter costs are <100bn AFAIC; and Germany alone (!!) projects more than that (top end) for grid expansion/operation within 2040 (mainly north/south and offshore connectivity).

[ben_w]

Putting this note first, because it's probably the main point of confusion/surprise: I did say "bill of materials"; the estimated full cost for European and US grid upgrades that we need anyway for other reasons, with far less material, is order-of a trillion or so for US, half a trillion for EU.

For the material cost, just applied maths. By sheer coincidence, 1Ω of aluminium around the world is very close to 1m^2 cross section: https://www.wolframalpha.com/input?i=40000km+*+resistance+al...

This is almost exactly 1e8 (100 million) tons: https://www.wolframalpha.com/input?i=40000km+*+1m%5E2+*+dens...

This is $223bn at current prices: https://www.wolframalpha.com/input?i=40000km+*+1m%5E2+*+dens...

For scale, this is about what China makes in 2 years; if this is rolled out over 30, which would be optimistic but plausible, it's within the realm of just how much China increased production between 2023 and 2025, being spent every year.

To get to 10x ITER's own estimate for ITER, the wikipedia page says the organisation estimates the reactor will cost about €18-22bn: https://en.wikipedia.org/wiki/ITER

There are a lot of reasons not to do this as a single big 1m^2 "wire", amongst them being that the surface magnetic field is strong enough to be dangerous to approach with ferrous materials.

[myrmidon]

The "square meter of aluminium" is an interesting take. Not sure how much power you'd get over that thing; extrapolating from existing HVDC systems (Inga-Shaba is 1GW over 2x520mm²), I'd expect around 1TW, so twice the US demand?

But because Nimbys have no appreciation for beautiful pylons, projects in that direction are doomed for now anyway and everything needs to be buried underground at extra cost :(