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Comment by sir_bearington | Hacker News Reader

> Bingo. Nuclear is just ridiculously expensive compared to Wind/Solar. You could overbuild 2-3x and maybe even add batteries.

Batteries will never have sufficient capacity to delivery any meaningful amount of storage. This is why any realistic plan for a wind + solar grid assumes some silver bullet will solve the storage problem: synthetic methane, hydrogen, thermal batteries, something else.

But who knows if any of those will actually pan out. California has already hit saturation with solar power. Adding more solar only marginally displaces carbon emissions. As far as actual decarbonization goes, nuclear is more valuable than raw generation figures present because this power is generated 24/7.

> RIP, only France did nuclear right :(

And Belgium. And Slovakia. And China.

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> Batteries will never have sufficient capacity to delivery any meaningful amount of storage.

What physical limit prevents this?

It would be expensive, but cheaper than building nuclear power plants, especially the breeder reactors that would be needed for a fully nuclear world economy.

Pumped hydro is pretty interesting, but highly dependent on natural elevation changes to be considered remotely economical.

Isn't pumped storage hydro kind of that "silver bullet"? At least in places with the right geography?

Pumped hydroelectric has good capacity, but doesn't scale well. The right geography is the main limiting factor, accessibility is a second. The places with good hydroelectric potential tend to be very remote, in the mountains. It's extremely hard to do large earthmoving and concrete construction in remote places. The places that have simultaneously the right topology and relatively easy accessibility are limited.

The alternative is essentially big water towers, and that has serious construction challenges not solved yet.

Pumped thermal storage has no geographic limits. The idea is: compress argon, transfer the heat to thermal store, expand the argon back to the starting pressure to recover some work, then transfer the "cold" to another thermal store. For long term storage, use very cheap materials, like rocks, for the thermal stores. To discharge, reverse the flow, so argon is cooled, then compressed, then heated, then expanded. All this can be done with existing technologies and with a round trip efficiency of perhaps 60%.

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