this post was submitted on 15 Oct 2024
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[–] [email protected] 5 points 2 months ago (2 children)

Nuclear is an excellent compliment to renewables and as a companion source to support the grid they are actually really effective.

No, it isn't. The nuclear industry wants this to be true, but an overview of the benefits and problems with wind, solar, and nuclear put it to rest.

What nuclear is really good at is providing baseload power; it runs for 30+ years at the same output with relatively little maintenance and fuel costs. Wind is good at being cheap when the wind is blowing. Solar is good at being cheap when the sun is shining.

The problem with nuclear is it has incredibly high up front costs, which need to be amortized over its lifetime; you can ramp it down, but you're cutting into your profits by doing so. The problem with wind is that the wind doesn't always blow, and the problem with solar is that the sun doesn't always shine.

Solar and wind are both incredibly cheap when they work. So cheap that we wouldn't want to use anything else if we can avoid it. Meaning we'd need to ramp down what nuclear and anything else is doing. Except now we're just making nuclear's up front cost issue worse; we can't amortize the cost as well when it's ramped down. You could try adding storage capacity so you can run all three at once and use it later, but then we could just use that storage for wind and solar on their own.

What you can do is take historical data on wind and sun patterns for a given region. The wind is often blowing when the sun isn't shining, and vice versa. We have lots of data on that, and we can calculate the maximum length of lull when neither will provide enough. So what you can do is put in enough storage capacity to handle that lull, and double it as a safety factor.

This ends up being a lot less storage than you might think. Getting to 95% renewables would be relatively cheap; Australia almost has enough storage capacity under construction right now to pull that off. That last 5% is harder, but even getting to 95% in industrialized nation states would be a big fucking deal.

Add in HVDC lines to this, and you've really got something. The longest one right now is in Brazil, and is 1300 miles long. That kind of distance in the US would mean solar panels in Arizona could power Chicago, and wind in Nebraska could power New York. At that point, the wind is always blowing somewhere, and sun is always shining somewhere else. You can also take advantage of existing hydro pumped storage anywhere you like--there may be enough of it right now that we wouldn't need to build any other storage.

[–] [email protected] 4 points 2 months ago

Your opinion is not really appreciated here with the nuclear industry trying to capitalise on the renaissance that seems to be fashionable these days. But I fully agree with your assessment, China is of course building nuclear plants, but have also seen the light in the sense that they are building more renewable generation capacity than all other generation sources combined.

Nuclear will not make a full ‘come back’, literally no one in their right mind is going to invest in 15 year projects when grid connected battery capacity is tripling every 6 months.

[–] [email protected] 2 points 2 months ago* (last edited 2 months ago) (1 children)

Just for another angle on the problem: baseload generation (nuclear) is most efficient at its highest possible output, but it has to maintain that output 24/7. It can't ramp up and down fast enough to match the demand curve, and it can't be ramped up above the minimum overnight demand.

To increase its efficiency, utilities push large scale consumers like steel mills and aluminum smelters to overnight shifts. This artificially increases the overnight demand, allowing the baseload generators to ramp up their relatively efficient production. This reduces the need for less-efficient peaker plants during the day.

That overnight demand can't be met with solar, and wind generation tends to fall overnight as well.

What nuclear can do is help level out seasonal variation, between the short days of winter and long days of summer. If you want to contemplate a truly pie-in-the-sky scenario, there are provisions for tying large ships, (like aircraft carriers and hospital ships) to shore power, and backfeeding the local grid to support disaster relief efforts.

Imagine a fleet of nuclear generation ships, sailing to northern-hemisphere ports from November to April, and to southern-hemisphere ports from May to October.

Pumped storage is also essential, but extraordinarily limited. We can probably run essential overnight loads on pumped storage, but it does not make sense to keep an overnight load on pumped-storage that can be shifted to solar/wind directly.

We need to take a look at demand shaping rather than supply shaping. We need to shift load to times we can produce, rather than shift production to times of demand.

[–] [email protected] 2 points 2 months ago

Sounds like demand shaping is already done, but not in a way that's helpful to renewables.