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Comment by cycomanic | Hacker News Reader

Economies of scale don't work for infrastructure. I mean if it would work for nuclear plants why have people not done it for coal plants? There have been many of them build, and a nuclear power plant is 70% the same as a coal power plant (which incidentally also explains much of the cost for nuclear power generation, it's essentially a thermal plant with added complexity, so can't really be significantly cheaper than a coal plant).

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Economies of scale are working great for solar. I suspect economies of scale don't work specifically for coal, because people don't want a bunch of pollution machines scattered everywhere. It's better to centralize and regulate pollution capturing, etc.

The fact that something hasn't been done is not necessarily evidence that it won't work. A few years ago you could have asked why everybody was still using disposable rockets, if reusables would be so great.

And coal is not exactly fertile ground for innovation, given that we'd like to stop burning coal entirely.

Matching the price of coal, with clean dispatchable power, is not such a bad outcome. There's a bit of wiggle room for extra complexity since coal pays 2 cents/kWh for fuel, and has to handle large amounts of incoming fuel and outgoing ash.

For a reliable zero-carbon grid of only wind/solar/battery, we need about 2X overproduction and 4 days of battery storage[1]. Maybe that still ends up the cheapest option, but it's not so obvious that a backup plan isn't worth considering.

[1] https://caseyhandmer.wordpress.com/2023/07/12/grid-storage-b...

Remember that nuclear is not that 'dispatchable': you need several hours/days to switch off or ramp up production.

Switch off (curtailment) is almost instantaneous for wind and PV.

And otherwise, batteries, hydropower and gas turbines are dispatchable on the second/minute scale.

I did mention batteries above, but that's a lot of battery. Hydro is great but not available everywhere. Gas turbines have substantial carbon emissions. Curtailment is fine but doesn't help on windless nights; what we need is power on demand, not just power available sometimes that we have the option to switch off.

How dispatchable nuclear is depends on the specific design, which is important given our context of small reactors with new designs.

According to the DOE, "Certain designs, like DOE-supported NuScale Power, LLC, can vary their energy output over days, hours and even minutes."[1]

According to NuScale, "The NuScale Power Module is capable of a ramp rate of 40% per hour in reactor power change, which aligns with specifications set by the Electric Power Research Institute (EPRI). For even quicker responses to electricity demand, the NuScale SMR can rapidly lower its electric power output up to 10% per minute and return to full output at the same rate utilizing turbine bypass. This is significantly faster than conventional nuclear power."[2]

More advanced designs may be even better.

[1] https://www.energy.gov/ne/articles/department-energy-report-...

[2] https://www.nuscalepower.com/-/media/nuscale/pdf/publication...

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