[turbinerneiter]

AFAIK nuclear output can be controlled only in a certain range, but if you go below a certain threshold it shuts off and you then have to restart it, which takes a lot of time.

Coal has a similar issue, these plants also can't be turned on and off quickly. In fact, the term "base load" originally was driven more by the minimum amount of power that has to be consumed to keep a plant running. Only now with the move to renewables with varying output the meaning has shifted to the consumption side of things.

Gas plants however can be turned on and off and easily, they work similar to aircraft engines. In Germany, the heat produced is then used for district heating, which gives these plants almost perfect efficiency. It's not a coincidence that Germany picked gas as supplement for renewables during the transition to 100% green energy. Gas (in the form of hydrogen directly ~ methane made from hydrogen) is also a key contender for very long term energy storage (in Germany, you have to save energy produced in the summer for use in winter, the batteries needed for that would be roughly in the order of ~50 million Tesla Model S (100kWh) batteries). The cost of overbuilding renewables and storing the energy in gas, with a lower round-trip efficiency, seems to be lower than building the big battery that would be needed. Wind is also better in winter than solar, which is why wind is such an important and hot topic in Germany. Solar doesn't bother anyone, but wind turbines are huge and people can see them in the landscape. Solar does not have this problem, but during the winter, the output goes down to almost nothing.

[ajuc]

Nuclear, coal, and gas powerplants only differ in how you produce heat. After that they work the same (heat water, make steam, drive turbines). There is usually a few stages of turbines to extract as much work as possible. Reaction time is 1 hour or more.

The waste heat can be used for district heating no matter how you produced the heat (in my city they use coal powerplant for this). It's not just gas. And it's not "perfect efficiency", it's about 80% for the best cogeneration powerplants compared to 60% without cogeneration. It's a little less in practice cause most powerplants aren't as modern and as efficient.

All of these is usually used on regular (not peaker) powerplants, because it's only useful if you use your powerplant for long periods of time.

There are also peaker powerplants. They work differently, and they are optimized for quick reaction time (so the energy they produce is more expansive and efficiency is lower). Reaction time is about 15 minutes. They don't only burn gas - they can also burn any liquid fuels (but gas is indeed the most common). Usually the efficiency of peaker powerplants is about 30-40%, can be almost as good as the regular ones but it's not worth it to install cogeneration if your plant runs for few hours a day.

I'm not sure which kind you were talking about. If they use cogeneration it means they must run for long time, and peaker powerplants running constantly is wasting money and fuel. Do you know what reaction time (from 0 to 100%) they have? 15 minutes or more like 1 hour? Or maybe less (then they are piston engines - and efficiency is even worse).

Anyway - there are also grid-scale batteries that can deal with power fluctuations on the order of milliseconds. That's why if you have lots of renewables and reasonably free energy market - grid scale batteries economically beat the crap out of peak powerplants (like gas plants).

In USA and Australia grid scale batteries already made building new peak powerplants unprofitable. It will soon happen in Europe too (unless lobbying stops this). Here [1] you can read more about how it works. It's basically the same advantage that High Frequency Trading has over regular traders on regular stock market. Just the difference isn't 1 second vs 10 milliseconds but 15 minutes vs 10 milliseconds. Before gas powerplant start up to produce the missing energy - the battery supplied it and shut down again. So now energy price lowered and gas powerplant has to either to produce that energy anyway and sell it for a fraction of price, or to shut down wasting fuel and not earning any money. And gas peak powerplants aren't designed for producing energy cheaply, they are designed for producing energy when there's shortage so energy is expansive.

So when you have grid scale batteries - they drive peak gas powerplants out of business :)

[1] https://caseyhandmer.wordpress.com/2021/05/20/the-unstoppabl...