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Re:Japan to invest on nuclear energy in major policy shift by cauch on Thursday December 22, 2022 @09:30AM (#34093582)
I think it's incorrect to say that nuclear does not require energy storage.

The energy demand is not flat, it has peaks. If you don't flatten these peaks with storage, you need to build a production system that should be able to generate enough energy during the peak, but then, some of the generators will have to be turned off the rest of the time.

To illustrate the idea, let me invent some numbers: with storage, you have, let's say, 10 power plants to build that are running relatively all the time, producing an integrated total of electricity of, let's say, 100. So, if you paid X$ for building the 10 power plants, you will have X/100 per unit of electricity. Without storage, you may end up with, let's say, 15 power plants, but some are turned off 90% of the time. At the end, you also produce an integrated total of electricity of 100 (the integral is the same, the time of consumption is just shifted to create peaks). The cost of build is now 1.5X, and you will have to 1.5X/100 per unit of electricity.

On top of that, turning on and off a nuclear plant is less efficient than producing continuously, so the price of electricity increase even more.

So, even with nuclear, storage needs to be built. Once the storage is built, it means that the problem of intermittence of renewable is way less problematic.

Re:Japan to invest on nuclear energy in major policy shift by neilwilson on Thursday December 22, 2022 @09:38AM (#34093671)
You export the electricity. Either directly, or by bottling it. Excess power always has a use.
Re:Japan to invest on nuclear energy in major policy shift by cauch on Thursday December 22, 2022 @09:54AM (#34093859)
Well, you cannot really export it if no one around needs it because they also are not in a peak. If they rely on importing electricity when in non-peak time, what do they do in peak time? By construction, the non-peak time is the worse time to export. Unless you export to a different part of the world, but then, the same argument works with renewable (said simply: if you can export at midnight to a country where it is 4pm, then you can use solar and import at midnight from a country where it is 4pm).

What do you mean by "bottling it"? Do you mean storage? Because that's exactly what I'm saying.

Re:Japan to invest on nuclear energy in major policy shift by ramesh31 on Thursday December 22, 2022 @11:37AM (#34095229)
>What do you mean by "bottling it"?

Aluminum production, for one example.

Bauxite is so cheap and abundant that the cost of aluminum is almost entirely in the electricity required for smelting, which makes it effectively equivalent to energy exportation.

Re:Japan to invest on nuclear energy in major policy shift by cauch on Thursday December 22, 2022 @12:08PM (#34095647)
Yes. It's basically demand response based on turning on and off factories.
Re:Japan to invest on nuclear energy in major policy shift by nradov on Thursday December 22, 2022 @12:57PM (#34096259)
No one is going to invest in an aluminum plant unless they have some assurance of cheap electric power for many years. The capital expense and fixed operating costs for those plants are tremendous. It's not economical to start and stop production on a daily basis as power prices fluctuate. How would you even schedule the production workers? And you still have to pay things like property taxes and insurance whether the plant is producing or not.
Re:Japan to invest on nuclear energy in major policy shift by m4rtink on Thursday December 22, 2022 @02:58PM (#34097820)
Also the local district heating company installed an electric 30 MW water heating boiler recently, which they can run on excess electric power and throttle down the regular combined cycle plant powered by natural gas.
Re:Japan to invest on nuclear energy in major policy shift by m4rtink on Thursday December 22, 2022 @11:54AM (#34095465)
Also IIRC you can design the reactors to support a degree of output scaling, if not shutdown. IIRC French reactors are designed to do that - they have some issues right now with premature fatigue but I'm not sure it is related.
Re:Japan to invest on nuclear energy in major policy shift by cauch on Thursday December 22, 2022 @12:12PM (#34095716)
Yes, I believe it's the case. The French nuclear plants can do some load following. But they are not doing it, because it's more inefficient for a nuclear power plants, and as the nuclear is anyway not 100% of the mix, the load following is done by the other parts of the mix that don't have such problem.

On my mind, the main problem of scaling down production for nuclear plant is that a nuclear plant is very expensive, and if it produces only at submaximal capacity, it means that the construction cost is spread on less electricity production.

Re:Japan to invest on nuclear energy in major policy shift by moloch-hai on Thursday December 22, 2022 @02:51PM (#34097732)
Operating a nuke at less than 100% is untenable: if run at 50%, each kWh costs twice as much as at 100%, but even running at 100%, it costs radically more than all other choices.
Re:Japan to invest on nuclear energy in major policy shift by KennyBlanken on Thursday December 22, 2022 @09:40AM (#34093685)
Exactly. People who shout about how wind/solar are not reliable and need storage / fossil fuel backup and then spout about nuclear have no idea how grid-scale energy generation works.

Nuclear takes hours to days to respond to load change, so there has to be much more reactive power available. And nuclear plants need to be able to draw megawatts of power from the grid any time they're not generating power. You can't "cold boot" a nuclear power plant without a massive external power supply and it takes days to weeks to do so.

It's so bizarre hearing people advocating for nuclear talking about storage like it's some barely-understood, dangerous, hideously expensive sci-fi pipe dream. Grid-scale energy storage is almost 100 years old and battery based systems have been actively deployed for many years at all levels of the grid, right down to residential.

Re:Japan to invest on nuclear energy in major policy shift by peterfirefly on Thursday December 22, 2022 @10:41AM (#34094447)
> Nuclear takes hours to days to respond to load change

Days? Seriously? You know that is not true, don't you? The French nuclear power plants are an existence proof of that.

Nuclear does need to be supplemented with something else with low construction/fixed costs for handling the rare, extreme peaks. That will most often be some sort of gas-powered plants. This has nothing to do with nuclear powers "inability" to "respond to load change" and everything to do with the cost of building enough nuclear power capacity that will almost never be used.

On the other hand, we are still very, very far from being able to do really large-scale battery storage. We don't have the manufacturing capacity for the enormous number of battery cells needed and even if we did, the cost would be prohibitive. This will of course change for the better in the future but that is how things are for now.

Re:Japan to invest on nuclear energy in major policy shift by cauch on Thursday December 22, 2022 @11:05AM (#34094775)
I thought French nuclear were only doing base load, the load following part being done by other sources.

I believe the French facilities have the capacity of doing load following, but are not doing it because it is less efficient (and therefore more expensive). So I would also not say "days", but it is also true that one cannot directly take a situation where nuclear has, so far, being used only for base load and pretend that load following will work exactly the same way.

I'm not sure why you say "rare, extreme peaks": the current demand is non-flat every day, with a difference between the trough and peak that is typically ~50% of the peak.

I agree that large scale battery storage is challenging. Maybe the solution would be to have some storage and some "wasted efficiency" by using nuclear plants in load following and turning them in stand-by every day during off-peak hours.

Re:Japan to invest on nuclear energy in major policy shift by Zopieux on Thursday December 22, 2022 @07:35PM (#34100920)
Correct, French nuclear is base load, but it still does a non-trivial amount of load following to e.g. absorb peaks. Check out [0] for some cool live graphs!

[0] https://www.rte-france.com/en/eco2mix/power-generation-energ...

Re:Japan to invest on nuclear energy in major policy shift by mlsu on Thursday December 22, 2022 @11:02AM (#34094737)
The entire United States has something like 3 seconds of energy storage, total.

Just getting that to an hour means a three order of magnitude change in the amount of connected grid storage. Good luck finding that much pumped hydro! The easy spots are taken already!

An hour is not enough, of course. That might handle some small variations in wind only. Of course, one diurnal solar cycle means you need to store power for 8-12 hours. That is another order of magnitude. So in order to do this, we need to increase our battery capacity by four orders of magnitude. Multiple days? Weeks?

Now consider that the demand curve will become even more extreme, as climate change increases demand for electric heating and cooling. And consider that you will also need to account for electrifying the cars on the road (because building out storage like this is a multiple decades project), which will place additional capacity demands on the grid.

The thing with storage is not that it's difficult, it's that it's big. Like the scale is you need to nationalize your extraction industries and turn your economy into a wartime economy whose singular purpose is producing batteries big. It's not a Tesla or Google or even a DOE scale problem.

Re:Japan to invest on nuclear energy in major policy shift by cauch on Thursday December 22, 2022 @11:15AM (#34094917)
Well, 3 seconds if you turn everything off, but it is not what we are talking about here, especially if the question is peak shifting. The majority of peak shifting is done at local level, with solution like, for example, domestic wall battery like Tesla or electric-vehicle-to-grid. Still not ideal, but I don't think your depiction of the situation is very fair if it presents it in a totally unrealistic way.

I also don't understand your argument about solar cycle: solar is producing close to peak hours, while nights are non-peak hours. So, in practice, it's not like you need to store the electricity locally for more than a couple of hours. I guess you are talking of a situation where the grid is 100% solar, but that's obviously a ridiculous scenario that no one has never pushed for.

I agree with the fact that the demand curve will become more extreme, and it is exactly the reason of my intervention here: this is a complicated situation, and it does not matter if the grid is mainly nuclear or mainly renewable, it is still problematic.

I agree that the storage problem is tricky and that the scale is a challenge. But this challenge still exist in full nuclear grid, unless we end up with a lot of idle nuclear plant running only few hours per day.

Re:Japan to invest on nuclear energy in major policy shift by VintageCool on Friday December 23, 2022 @02:12PM (#34109532)
The United States added more battery energy storage to the grid in 2021 than the United States had at the beginning of 2021. The situation here is one of rapid transition.
Re:Japan to invest on nuclear energy in major policy shift by liketochill on Thursday December 22, 2022 @06:56PM (#34100624)
Nuclear plants can respond to changes in reactive power demand in ~100ms. It is a function of the voltage regulator and not the prime mover. Perhaps you didn’t mean reactive?
Re:Japan to invest on nuclear energy in major policy shift by scythe on Thursday December 22, 2022 @10:07AM (#34093997)
Nuclear power needs storage on the scale of a day or two. Wind needs storage on the scale of a few weeks. Solar needs storage on the scale of 3-6 months. You can work around this a bit with demand scheduling and it's much less of a problem in the tropics, but we're talking about Japan: it's northern, densely populated and cloudy.

If you can turn a nuclear plant off (summer) and on (winter) once a year, the storage requirement for solar drops by a lot.

Re:Japan to invest on nuclear energy in major policy shift by cauch on Thursday December 22, 2022 @10:18AM (#34094144)
Sure, but

1) week storage and 3-6 months storage are extreme events, similar in probability as overlapping technical shutdowns in nuclear facilities. In practice, with interconnection, it is even arguable that such long term storage are even needed.

2) the technology built for short term storage is usually not that bad for medium term storage either. In any case, if you want a nuclear grid, you will need to invest in storage technology, and there is no reason the progress in those technology will only improve short term storage solutions.

But I 100% agree: a nuclear plant turned on during winter will help. I'm not against nuclear, I just want to react to the incorrect view that storage is just a renewable problem.

Re:Japan to invest on nuclear energy in major policy shift by moloch-hai on Thursday December 22, 2022 @02:56PM (#34097804)
There is, in fact, no need for "a few weeks" of storage anywhere for any reason, never mind months.

NG backup works fine, and will continue working fine indefinitely. Storage cuts the fraction of time the furnace needs to run.

Eventually, synthetic fuel will displace NG. It will be imported at need, same as NG today, but with no possibility of cartels.

Re:Japan to invest on nuclear energy in major policy shift by panick21_ on Thursday December 22, 2022 @08:08PM (#34101149)
Nuclear really only needs storage for a few hours, exactly what existing LiIon is already really good at, quick charge, quick uncharge.