IIRC nuclear doesn't really work well as the last 5-10%. Start-up and shut-down for nuclear reactors is a slow process. When it's generating, it needs to just keep on generating. Not so quick to dial down or up just because the wind is(n't) blowing.

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SoftTalker 4 hours ago | parent | next [-]

It's not that slow. They can ramp up and down over hours, and those demand patterns are known in advance. Combine with battery, pumped storage, or synfuel generation to soak up excess power during low demand times, and use that to provide peaker capacity during high demand times.

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cauch 3 hours ago | parent | next [-]

Demand following for nuclear is possible (after all, if you produce 10X but the demand suddenly drops to 7X, what you can always do is to "dump" 3X worth of steam instead of injecting it in the turbine), but because the cost of nuclear is mainly upfront, it is not cost efficient at all.

If it costs 10X dollars upfront to build a nuclear central that can produce 10X energy, then if you run it at 100%, it will cost 1 dollar per 1 unit of energy. If you follow the demand, you will not produce 10X, but let's say to illustrate maybe 5X, and it will cost 2 dollars per 1 unit of energy.

You are right about storage as a way to help with demand following, but if you build enough storage capacity, then you basically have solved "for free" a big part of the problem linked to the intermittence of renewables. In this case, you have the choice between building an expensive nuclear central and a distributed cheaper renewable generation.

I'm not saying it demonstrate renewables are better, but that it is true that nuclear is not the obvious winner it looks like before we look into the practical details.

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ViewTrick1002 3 hours ago | parent | prev [-]

The problem is the economics. They’re just horrifyingly expensive to build. The equivalent to each new large scale reactor in GWe requires tens of billions in subsidies.

The next problem comes from incentives. Why should anyone with solar or storage buy this expensive grid based nuclear electricity?

Why should their neighbors not buy surplus renewables and instead pay out of their nose for expensive nuclear powered electricity?

EDF is already crying about renewables cratering the earning potential and increasing maintenance costs for the existing french nuclear fleet. Let alone the horrifyingly expensive new builds.

And that is France which has been actively shielding its inflexible aging nuclear fleet from renewable competition, and it still leaks in on pure economics.

	▲	panick21_ 5 minutes ago \| parent [-]
		The French have used their nuclear system for 20+ years as a giving tree. The forced EDF to sell nuclear at very cheap prices to fossil fuel companies and then buy it back at much higher price. The French forced EDF to give subsides to solar even when that actually hurts their economics. The French randomly in the 2010s decided to replace nuclear in a short time-frame (completely 100% unrealistic) but it sounds good to politicians. And they decided to delay all maintenance and didn't do any of the upgrades many other nations did. Once of the secrets of French nuclear is, that their grandfather were so good in providing them these nuclear plants, the french absolutely suck at running them. Other countries like the US and ironically Germany managed to run their reactors at higher factors. The problem is the solar is cheap when its being produced and makes the economics of base lose worse, without actually solving base load. Solar has been cross subsidized this way for a long time. And has been more explicitly subsidized. But its a private good, it helps only private people, it is negative on a system level. Once you think on a systemic level, how to provide reliable energy for a whole country, nuclear is not more expensive and France saved a huge amount of money buy doing what they did. > Why should anyone with solar or storage buy this expensive grid based nuclear electricity? If somebody privately wants to build solar/storage that's fine, but they should get no support. Also prices should be adjust to actually reflect peak demand. Historically the way the system operated is with much simpler pricing models because it was understood that everybody shares in this infrastructure. In such a situation, the majority of people wouldn't build solar and batteries. But really, the question we should ask, what the best thing to run a modern economy on and the German solution of 'lets build a massive electricity pipeline to solar farms in Greece' isn't a great model. All this new energy transfer infrastructure is incredibly expensive. It cost at least as much as the generation itself, and sometimes more.

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panick21_ 15 minutes ago | parent | prev | next [-]

First of all its not that slow, and when you know when you need it, at what point in the day, so you can ramp up in anticipation.

Also, the claim that nuclear is slow to change is a limitation of current nuclear plants, more modern plants could be far better. Some designs are very much load following.

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pfdietz 2 hours ago | parent | prev | next [-]

The problem isn't technical dispatchability, it's economic dispatchability. A nuclear plant operated at 5-10% capacity factor would be ludicrously uneconomical, even to just operate.

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zozbot234 3 hours ago | parent | prev [-]

It's not a technical limitation, it's economic. The cost of nuclear is almost all in building (and decommissioning) the plant, the fuel is almost free. So you want to produce flat out as long as you can get almost any positive price for the output.