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How the electricity markets respond to a nuclear trip

blog.gridstatus.io

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Re: How the electricity markets respond to a nuclear trip

#51

Post by seoulmetro »

toomuchtodo wrote: post #2

Something interesting is that with substantial solar and batteries being deployed in the ERCOT market (in scope grid operator for this piece), solar generation in excess of what the grid can consume with load combined with grid forming inverters (vs traditional grid following) can step in when called upon if a traditionally firmer generator (coal or nuclear) trips out. The potential is already there (photons hitting…

Something less interesting and more annoying is that in power generation surpluses instead of doing this, the government can just mandate that you buy power from them instead of get it free from the sun.

Because a few hundred thousand chips in solar systems costs less than an entire network rethink.

Re: How the electricity markets respond to a nuclear trip

#52

Post by lmm »

huijzer wrote: post #11
toomuchtodo wrote: post #2

Something interesting is that with substantial solar and batteries being deployed in the ERCOT market (in scope grid operator for this piece), solar generation in excess of what the grid can consume with load combined with grid forming inverters (vs traditional grid following) can step in when called upon if a traditionally firmer generator (coal or nuclear) trips out. The potential is already there (photons hitting…

An individual inverter can usually switch in about 4 ms. A Tesla Megapack can go from 0% output to max output in 100 ms. Conversely, gas turbines (the fastest type of traditional power plant) takes about a minute to go from say 40% to 60%. Even in the fastest possible design, there is a mechanical rotor (kinetic energy) that has to change speed. What I mean to say is that solar and batteries are likely an order of ma…

> Even in the fastest possible design, there is a mechanical rotor (kinetic energy) that has to change speed.

The point of ramping up the power plant is to make sure that the rotor doesn't change speed (by e.g. burning more fuel to push it harder, because there's suddenly more load on it), and that can happen a lot faster than spinning up the rotor from scratch. Indeed a heavy rotor helps to stabilise the grid "for free" by acting as a flywheel (which, in a way, responds even quicker to the demand change than a battery can).

Re: How the electricity markets respond to a nuclear trip

#53

Post by m463 »

jeffbee wrote: post #45
bell-cot wrote: post #34

Earlier quoted context omitted.

The maximum slow-down of the turbines (before the generator trips off-line, removing the load on it) is far less than you seem to assume. The article's graph shows the 60.00Hz grid frequency dropping...all the way to 59.92Hz. That's 0.1333%. For an on-line gas turbine, the time to ramp up production is the second or few needed for the automated controls to open the throttle on the "Gas IN" pipe. It's basically a natu…

The more interesting thing about rotating power plants is that they are routinely destroyed by transmission outages, because when a rotating generator is suddenly disconnected from its load, there are infinity terms in the equations that govern its motion and infinity isn't a thing you can resist. For steam turbines the control system has to slam the valve shut on the steam, otherwise the machine would overspeed, and…

I don't see why there can't be load resistors (like locomotives use) to gracefully handle these sorts of situations.

Re: How the electricity markets respond to a nuclear trip

#55

Post by pfdietz »

rtkwe wrote: post #9
kccqzy wrote: post #4

Earlier quoted context omitted.

Most curtailment IIRC is due to insufficient transmission capacity. I doubt curtailed solar can be called upon in an emergency unless the emergency is located very close to the curtailed solar.

The transmission lines run to solar farms should be able to take 100% of the output of the farm and then some otherwise the farm was over built and wasted money.

If by output you mean the maximum output of the inverters. The maximum output of the PV modules can be higher, particularly if the field has integrated batteries.

Re: How the electricity markets respond to a nuclear trip

#57

Post by pfdietz »

energy123 wrote: post #46
rtkwe wrote: post #9

Earlier quoted context omitted.

The transmission lines run to solar farms should be able to take 100% of the output of the farm and then some otherwise the farm was over built and wasted money.

That's not necessarily optimal. For home installs, you can overbuild panels because they're cheap compared to the inverter. Then you curtail sometimes at midday and have extra energy on cloudy days and in the morning/afternoon. Turns out that's more cost effective than sizing the panels perfectly. The same logic could apply to utility farms, because transmission lines can be expensive. I don't really know myself sinc…

It definitely applies to utility builds. It applies even more if the DC power from the modules can also be used to directly charge batteries.

Re: How the electricity markets respond to a nuclear trip

#58

Post by Qwertious »

m463 wrote: post #53
jeffbee wrote: post #45

Earlier quoted context omitted.

The more interesting thing about rotating power plants is that they are routinely destroyed by transmission outages, because when a rotating generator is suddenly disconnected from its load, there are infinity terms in the equations that govern its motion and infinity isn't a thing you can resist. For steam turbines the control system has to slam the valve shut on the steam, otherwise the machine would overspeed, and…

I don't see why there can't be load resistors (like locomotives use) to gracefully handle these sorts of situations.

Well if you can solve it, I imagine there's a lot of money to be made - and yet it hasn't been solved.

Re: How the electricity markets respond to a nuclear trip

#59

Post by ViewTrick1002 »

leymed wrote: post #47
ViewTrick1002 wrote: post #40

Earlier quoted context omitted.

Reliable until it isn’t. The entire grid is a statistical system where we define the acceptable uptime. Renewables are as good as any other energy source bringing its own fuel, just need to take the variability into account. https://www.nytimes.com/2022/11/15/business/nuclear-power-fr...

You’re correct that the system is statistical, and it’s planned accordingly. However, we cannot omit the fact that it’s the running turbine that responds faster to the unpredictable nature of the grid. The backbone of the grid, aka the baseline plants, are extremely responsive to unpredictable nature of the grid at a greater scale, with enough amount of safety margins to bring into service under unusual circumstances…

Which means nuclear is the worst companion imaginable. Since nuclear power needs to run at 100% 24/7 to only make an enormous loss.

Dispatchable nuclear power to complement renewables has never made sense.

Re: How the electricity markets respond to a nuclear trip

#60

Post by Symbiote »

pstrateman wrote: post #8
Symbiote wrote: post #3

Where does the 1500MW of heat the reactor is producing go, immediately after the generators are isolated from the grid?

Enthalpy of vaporization for water is very very large. The amount of heat that can be dissipated by evaporating water is kind of incredible.

Thanks, that's what I was asking.

(It's obviously not a meltdown situation!)

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