zlacker

>>RobinL+(OP)
Curtailment, like negative prices, seems like something that it is hard for people to have constructive conversations about.

Probably the cheapest and best option is to build more wind and not care too much if it increases curtailment.

Yes, all the things mentioned should be looked into and done when it makes financial sense but "wasting wind" is much less a thing to worry about than "burning gas", and I'd rather waste wind than waste money.

>>ZeroGr+k8
Balancing a nationwide power grid is very complex. Some energy sources can be started and stopped instantly, but are limited - water. Others are plentiful, but unpredictable - wind. Others are predictable, but take a long time to start and stop - gas, coal(several hours), nuclear(1 day to start, fast to stop, but very expensive). A balanced grid will need all of them, will need them in quantities which can cover faults in the big producers(a nuclear reactor makes 700-800 MW). They will need them built in the right place, because while more power cables can be built, you can't transfer a lot of power on very long distances, for cost and grid stability reasons.

>>redlea+ud
Nuclear power plants can vary their output faster than most people think, see

https://www.oecd-nea.org/upload/docs/application/pdf/2021-12...

   ... 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.

One trouble is that changing the power output does put stress on components because of thermal expansion and contraction, potentially shortening their lifespan, but it something that can be designed for.

>>PaulHo+pn
Varying output from a nuclear plant is mostly achieved by simply releasing the generated steam into the atmosphere instead of sending it through the turbine[1].

But operating a nuclear plant in this fashion pushes up the price per MWh considerably given their very high cap-ex and op-ex. And while fuel cost is negligible for nuclear, creating more nuclear waste per useful MWh generated is a further drag on costs.

So as a solution, it "works" if the nuclear plant does not have to compete in terms of price with other sources of electricity. But nuclear fails to compete on cost even if operated continuously - it's uncompetitive with cheap, quick to deploy, low op-ex, modern tech like CC gas turbines or renewables in most western electricity markets and can only survive with government subsidy[2].

[1] https://www.nrc.gov/docs/ML0703/ML070380209.pdf [2] https://www.washingtonpost.com/business/2022/04/19/biden-adm...

>>derriz+HJ
Your reference for [1] just states that bypassing the turbine is a thing, not that it's normally used.

First, reactors are in a stable equilibrium when operating, so one will actually increase their power by increasing the rate at which heat is removed (and v.v.). Alas, that's workable only within some small range.

A reason[1] load-following with PWRs was originally difficult is that traditionally PWRs use boron concentration in primary loop to regulate power and that can be decreased only slowly. The reason it's done that way is that it's the easiest way to ensure that power is adjusted uniformly throughout the core; if instead some control rods were partially inserted, the top part of the core would operate at lower power (and thus lower fuel burn-up) than the bottom part, which would cause compounding control issues later on.

France is using their PWRs in load-following mode by (a) having additional less absorptive control rods ("gray rods") that can be inserted fully to adjust power by smaller increments (b) more complicated schemes to decide which combination of available actuations to use to change power. See https://hal.science/hal-01496376/document for a paper that tries to optimize control designs so that power changes are more possible (and describes how the control schemes work).

Note that the total heat capacity of even just the primary loop in usual reactors is quite large: in PWRs it usually requires ~0.5s of full power output of the reactor to warm it by 1degC, so this can easily cover, say, ~5% variations for something like a minute.

[1] Another is that reactors are not stateless due to xenon poisoning.