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Comment by amluto | Hacker News Reader

Nuclear fuel is cheap enough that it could be economical to simply [0] discard the unneeded production.

[0] It’s not that simple, but dump loads exist, as do mechanisms to intentionally waste power inside a plant without producing electricity. For example: https://www.thermal-engineering.org/what-is-turbine-bypass-s...

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The other capital and operational costs stay the same even if you just discard the production you don't need, so just focusing on fuel costs is not very helpful to determine if it's economical to do that.

Financial profitability is not a requirement for infrastructure projects. If it is the best way to supply power in the most sustainable way, it should be subsidized by governments to make it happen. If you want to pretend it balances on paper add eco taxes elsewhere, but again thats not necessary.

It is not that easy, we have privatised the energy markets so there are rules that need to be followed. Ignoring cost is not something governments can or should do, there are many more factors that need to be taken into account and this combination is what should be optimized for instead of just one factor. The most sustainable way to supply power is to reduce the need to supply it in the first place, insulation and other energy saving measures are usually subsidized already.

My point is that, once you’ve paid the capital cost for, say, 1GW of nuclear, the marginal cost of energy produced is low and you can adjust the production on fairly short timescales. I’m not saying you should, but the calculation is different from a natural gas or coal plant in which the marginal cost of energy is much higher.

The OpEx is coal < nuclear < gas [0]. This is for regular nuclear plants, SMRs will have higher OpEx. Not sure how they'll fare against gas exactly. The SMR handbook has some estimations I believe, but I don't recall the numbers.

[0] https://www.e-education.psu.edu/eme801/node/530

This is the actual plan for renewables, because they are just cheap period (though their fuel is pretty darn cheap too). Demand response, simply dumping the excess, storing excess as heat etc.

It's not a good idea for nuclear, because even nuclear that runs all the time can't compete on cost with renewables and any deviation from that schedule destroys the economics conpletely.

A small amount that runs all the time is probably a good idea in places far from the equator, but even then the plummeting costs of renewables opens a few other doors, like shipping green hydrogen around.

Right, any dollar diverted from renewables + storage to anything else, whether nukes or gas, brings climate disaster ever nearer.

24 GW of renewables in my country are not delivering even 1 GW when demanded currently.

That's not demand response. That's failure.

Sounds like a case for Bitcoin ASICs if I've ever heard one . . .

Can machines for extracting CO2 from the atmosphere have how hard they are running be ramped up and down quickly? Or do they just have a rate they work at, where changing how much one is doing would require changing how much machine there is / which ones are active ?

Machines for removing CO2 from the air need consume no power at all. (E.g., a big fabric corral that waves slop into, connected to a fabric tube 10 m across that opens 1000m below.)

Machines to synthesize H2 and NH3 could be ramped up and down, but in practice will run 24/7 except when price peaks and stockpiles are burned for power instead.

> Nuclear fuel is cheap enough that it could be economical to simply [0] discard the unneeded production.

Just run wind turbines backwards, easy!

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