[martinald]

Yes but you need 10s or 100s of GW of hydrogen electrolyzers, which are expensive, and they will only be running a small % of the the time (when there is excess renewables).

I'm not sure how much existing natural gas infrastructure can be reused given how much lighter hydrogen is and I assume it needs much tighter tolerances on all the equipment compared to natgas.

[adrianN]

Yeah, true. But it turned from a "we don't have enough of element XY on Earth to build that" to a "it sounds kind of expensive" problem. As it turns out people did the math already and building the hydrogen infrastructure is probably not prohibitively expensive, in fact it might turn out to be reasonably cheap. There is a tradeoff between overbuilding renewables, improving the grid, making the demand side more dynamic, and storage.

[martinald]

Yes, but my point isn't so much it couldn't ever be done, it's that by the time you upgrade the grid massively, build the renewables, build the electrolyzers, build the hydrogen infrastructure and the infrastructure to convert it back to electricity, it's almost certainly way more expensive than already expensive nuclear to build.

[adrianN]

The experts tend to disagree.