Nuclear plants provide base load and they are extremely fast at ramping up/lowering production. All modern nuclear plants are capable of changing power output at 3-5% of nameplate capacity per minute: https://www.oecd-nea.org/upload/docs/application/pdf/2021-12...
You don't shut down power plants. None of the power plants ever do a "fast cold start"
> The end result now is that electricity in Europe is the most expensive on the World, so all manufacturing is moved to Asia
The production moved to Asia due to extremely cheap labor, not due to electricity costs.
And all of this is confused by the way the nuclear industry uses the term "load following". You'd think it means "changing the power output from moment to moment to match electricity demand" but for nuclear plants it means "changing from one pre-planned constant level to another pre-planned constant level, up to four times per day".[0] There are only three[1] sources of electricity that can be ramped freely enough to exactly match demand: hydro, simple-cycle gas turbines and batteries. All electrical supplies will need some of those three mixed in. Which is why France is still 10% hydro and 10% natural gas in their electricity supply.
0: Some of the most modern Russian plants can move to +-20% of their current target at 10% per minute, but "the number of such very fast power variations is limited, and they are mainly reserved for emergency situations." per your source.
1: OK, there are some obsolete ways too, like diesel generators. At least obsolete at the scale of the electricity grid.
5% of nameplate capacity.
> You'd think it means "changing the power output from moment to moment to match electricity demand" but for nuclear plants it means "changing from one pre-planned constant level to another pre-planned constant level, up to four times per day"
Which is clearly invalidated by the very source I provided, and which you then somehow quote back at me.
> "the number of such very fast power variations is limited, and they are mainly reserved for emergency situations." per your source.
Imagine if you didn't omit the full quote/context:
--- start quote ---
Also, AES-2006 is capable of fast power modulations with ramps of up to 5% Pr per second (in the interval of ±10% Pr), or power drops of 20% Pr per minute in the interval of 50-100% of the rated power. However, the number of such very fast power variations is limited, and they are mainly reserved for emergency situations.
--- end quote ---
Oh look. What's limited is an actual emergency ramp up of 5% per second or power drops of 20% per minute.
Which is literally an emergency that is not needed in a power grid.
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Let me quote page 10 of your source "In brief, most of the modern light water nuclear reactors are capable (by design) to operate in a load following mode, i.e. to change their power level once or twice per day in the range of 100% to 50% (or even lower) of the rated power, with a ramp rate of up to 5% (or even more) of rated power per minute". Your own source defines "load following" as changing the targeted power level once or twice per day.
Again on page 14 (about how the French currently run their nuclear plants): "The nuclear power plants operating in the load following mode follow a variable load programme with one or two power changes per period of 24 h". Weirdly enough this is contradicted by table 2.1 on page 20 where they do four changes per day.
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> Oh look. What's limited is an actual emergency ramp up of 5% per second or power drops of 20% per minute.
If you look at table 2.4 on the same page it states that it (the Russian VVER-1200) can do the 5% per second/20% per minute emergency change 20 000 times over the lifetime of the reactor. The 10% per minute change can also only be done 20 000 times over the lifetime of the reactor. Table 2.2 on page 21 helpfully calculates that 15 000 cycles is once per day for 40 years, so the VVER-1200 only can do a bit more than one >5% change per day (outside of emergencies) assuming a similar 40 year lifespan. And that was the point of my footnote: that nuclear plants technically can go faster than 5% but not up and down on a minute-by-minute basis.
> None of the power plants ever do a "fast cold start"
Somewhere in each grid you will have “black start” capacity contracts, dunno if nuclear can fills this role (or if grids exclude nukes for one reason or another).
Plenty of peaker plants built with the intention of running double digit hours per year and therefore the tradeoff supports being largely “off” in between those calls. Batteries might fill that gap.
The obvious counterexample is Chernobyl, where a big contributor was the fact that they were unable to scale it down & back up as desired. Yes, nuclear reactors can scale down rapidly - but you have to wait several hours until it can scale back up!
Besides, the linked paper only covers load-following in a traditional grid (swinging between 60% and 100% once a day) and barely touches on the economic effects. The situation is going to look drastically different for a renewables-first grid, where additional sources are needed for at most a few hours a day, for a few months per year.
> You don't shut down power plants. None of the power plants ever do a "fast cold start"
Gas turbines can. Hydro can. Battery storage can.
If you are going to curtail, you curtail other sources including solar and wind.
Nuclear fits quite well for the baseload you need. It's more expensive, but if you are going to need X capacity 24x7 and build nuclear, you simply build enough to provide just that plus perhaps a few extra for redundancy when another one goes offline. Then use gas peakers for the "oh shit" days difference between what nuclear is providing and solar was expected to but could not.
I don't understand the fascination folks have about nuclear not being able to following the grid. They don't need to, since they only ever remotely make sense when operated 24x7 at 100%. If you always have 1TW of grid usage every night during your lowest usage period - build that much nuclear as your starting point and figure out the rest from there. Nuclear's share of the total mix should be a straight line on a graph outside of plant shutdowns for maintenance.
Your argument only works in entirely state controlled systems, not in free energy markets of independent suppliers. Which is why nukes don’t get built.
You mean the obsolete design that is not used even in old reactors, not to say of modern designs?
Quote:
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The minimum requirements for the manoeuvrability capabilities of modern reactors are defined by the utilities requirements that are based on the requirements of the grid operators. For example, according to the current version of the European Utilities Requirements (EUR) the NPP must at least be capable of daily load cycling operation between 50% and 100 % of its rated power Pr, with a rate of change of electric output of 3-5% of Pr per minute.
--- end quote ---
> The situation is going to look drastically different for a renewables-first grid, where additional sources are needed for at most a few hours a day, for a few months per year.
Ah, to live in these mythical times...
