857
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
this post was submitted on 11 Aug 2024
857 points (99.1% liked)
Mildly Interesting
17350 readers
60 users here now
This is for strictly mildly interesting material. If it's too interesting, it doesn't belong. If it's not interesting, it doesn't belong.
This is obviously an objective criteria, so the mods are always right. Or maybe mildly right? Ahh.. what do we know?
Just post some stuff and don't spam.
founded 1 year ago
MODERATORS
At risk of starting a whole new fight, this is why hybridizing renewables with nuclear doesn't work. They don't cover for each other's faults very well.
Nuclear isn't particularly good for leveling the daily demand curve, no.
But, it can be very useful for leveling the seasonal variation. Slowly ramping up nuclear production to make up for the short winter days of December, January, February. Slowly rolling it back for the long summer days of June, July, August.
Nuclear is also an excellent option for meeting overnight demand.
But you're right: it is terrible for making up for inclement weather, and other short-term variation. We will continue to require short- and medium-term storage. We will continue to need peaker plants, although we will hopefully be able to fire them with hydrogen instead of carbon-based fuels.
Which isn't actually necessary. Winter has less sunlight, but also more wind.
We can be smart about this. We have weather data for given regions stretching back decades, if not more than a century. We can calculate the mix of power we'd get from both wind and solar. There will be periods where both are in a lull. Looking again at historical data, we can find the maximum lull there ever was and put enough storage capacity to cover that with generous padding.
And then you just don't need nuclear at all. Might as well keep what we have, but no reason to build new ones.
Baseload storage is a pipe dream. The storage and generation capacity necessary to make that work would be about two orders of magnitude more expensive to maintain and operate than the equivalent nuclear capacity, and the environmental impact would be far greater still.
That's not to say that storage is useless; it certainly isn't. But its utility is in leveling spikes and dips, not replacing baseload generation during a "lull".
That's simply not true. This has been well studied, and a 100% renewable + storage option is quite feasible. It's even easier if you focus on going 95% first (that last 5% gets much, much harder).
https://www.amazon.com/dp/1009249541/
Depends on your definition of "feasible".
It is certainly within the capabilities of humanity to do it.
It would cost far more, and have much higher ecological impact than alternatives.
To me, that is not "feasible".
It's feasible and cost effective. The academic research on this has been quite clear, but it isn't the sort of thing that generates headlines. Nuclear just isn't necessary.
And don't forget that the plants are really expensive. Having them produce very little or even no power for half the time doesn't help that at all.
The trouble with that kind of variation is that the economics of nuclear don't make much sense. Nuclear is a large up front investment with (relatively) low marginal cost. If it's running at a low level for half the year, then it can't make back that huge initial investment in its expected lifetime.
We are currently charging very low overnight rates because we need to increase night time load on nuclear. With solar and wind being cheaper, grid operators are going to want to drive consumers to daytime consumption wherever possible. Night time rates are going to naturally increase, and I would expect artificial incentives on top of that to drive as much consumption as possible to the day, especially to clear, windy days.
The alternatives to nuclear are pumped storage, (which isn't sufficiently scalable); traditional baseload generation (which is significantly more expensive); and various forms of peaker plants (which are much more expensive).
Basically, overnight and winter rates are going to rise to wherever nuclear needs them to be to remain profitable, because every other option has either limited feasibility, or higher costs.
You left out a large number of storage options. There's plenty out there. Not every one is going to work for everything, but there's almost always something that's going to work.
Storage is important, yes, but it's mostly a pipe dream. Few grid scale storage options are sufficiently scalable, and all storage is inherently inefficient.
We have a steel mill. We currently run it on nuclear power, overnight, during off-peak hours. If we want to switch it from nuclear to solar, do we continue to operate it at night off of pumped storage and batteries? Or do we move it to daytime operations? The former is "supply shaping": adjusting our production to meet demand. The latter is "demand shaping": adjusting our consumption to meet available supply. That's the kind of thing we need to focus on.
At home, the single most important thing we need is mixing valves on our hot water tanks. These add cold water as needed to maintain a constant output temperature. This allows a variable, smart thermostat on the tank, that will superheat water when power is cheap, and let it fall when power is expensive. When solar excesses push rates too low, all of our water heaters start kicking on, sucking up cheap power during the day, and holding it through our night and morning showers.
ok just so we're clear here, you wouldnt ramp up or down nuclear power output, unless you're doing maintenance. It's at or near 100% power output, always. Most plants sit at a capacity factor of about 80-90%
You would however, ramp down wind turbines, or dump solar, or even store that solar since you're in a peaking cycle.
Solar and wind are cheaper and potentially more plentiful, more distributed than nuclear. Renewables are going to be the primary source of power; nuclear and every other type of generation will augment the renewables.
What you're saying is what nuclear has been, not what it will be.
potentially, that's always an option, but unlike something like oil where it's a generic concept, energy is kind of an ethereal concept. I see it much more likely that if nuclear plants get sufficient development time and funds, that they will pair nicely with renewables as you can buy the electricity wholesale at price, but the versatility of the pricing will offset the increased cost as you can subsidize it using cheaper renewables.
Allowing you to minimize energy storage and some amount of renewable production as well.
I wouldn't be surprised if grids ended up using solar primarily for day time production consumption and short time storage (evening consumption time) and then used nuclear as the primary producer for power consumption over night, along with wind somewhere in the mix. But this would require nuclear power to be built in the first place.
Exactly. Nuclear carries us overnight, renewables meet our needs during the day.
Negative rates aren't caused by excess solar. Negative rates are caused by excess overnight demand. Overnight demand is too high, necessitating the continuous nuclear output to be set too high. The sum of the continuous nuclear and the daytime solar exceeds daytime demand; rates go negative to correct.
The solution is to remove nighttime demand. Now the continuous nuclear output can be reduced. This is exactly opposite of what the grid needed before renewables, but it is the only viable approach moving forward. The other half of the solution is to add daytime demand, perhaps the same demand we removed from overnight; perhaps an entirely new way to turn power into profit.
(Nuclear plants won't actually reduce their output. Coal plants will go offline, and nuclear will take over their customers.)
oh well if you're arguing for shutting down nuclear, it's a bit different of a story. You should probably change your phrasing to reflect that lol.
I mean, long term, nuclear should probably go away, but that's a distant objective. I'm talking about the next few years, not the next century.
The next major stage is to reorient the grid away from the traditional, supply-shaping "baseload + peaker" model that benefits from increased overnight demand. That model is replaced with a demand-shaping, "use it when it's easiest to produce" model.
To get from here to there, we need to reverse the incentives that drive overnight consumption. This in turn lowers overnight demand. That reduction in overnight demand calls for a reduction in baseload supply, which reduces baseload generation at night and during the day as well. A reduction of baseload during the day means less surplus power is dumped, and more is sold.
ok so, solar, naturally produces the most power during the daytime, when the sun is up, which in places where it's warm is when you get the most significant energy bump due to AC and what not. There is also a bit of a trailing period in the evening where people get back from work and cook dinner/relax and whatever. But that's not super far off from noon peaking in the grand scheme.
Nuclear plants are baseload, so they produce 100% power output for 100% of the time they exist (at least in an ideal world) usually they have a capacity factor of about 80-90% though i've seen plants go past 100% before. This load is super useful for leveling out the power demand overnight, as well as shortening the day time peak loading a little bit. As well as providing a very consistent and regular source of power than can be used for things like hydro storage, and battery charging for example. So paired with a large thermal battery a nuclear plant might even be able to adapt to the midday loading cycle pretty functionally, as it can recoup most of it's lost energy over the night, through the baseload averaging out.
Nuclear plants are actually really well suited to be used with a thermal battery solution (given that they output thermal power, obviously) It's more common for modern plant designs to integrate thermal battery technology to some degree, but those are all gen IV designs, so they don't exist yet.
As for wind, i'm not sure what the effects on it during the day/night cycle is, but i imagine during the day they generally produce more power, though they will also produce some power over night. So those are a relatively low yield but high regularity power source, similar to nuclear, however you have much greater control over them as you can change the blade pitch during rotation in order to increase/decrease output as needed. Though ideally you would always be outputting, as often as possible.
Even in the event that you have a total grid blackout, nuclear plants are a potential source of blackstart power sources, though presumably it's not nearly as big of a deal in a solar plant for example. It's unclear how much those rely on being secondary producers, or how well they can function as primary producers to me. Presumably it will be dealt with at some point if it hasn't been already.
Ignoring the paragraphs of mansplaining about how nuclear works . . .
Wind speed at 100m tends to drop in the late afternoon and pick up during the night. See page 49 here:
https://www.nrel.gov/docs/fy15osti/61740.pdf
What? No. Much of the Ercot failure in Texas to deal with the 2021 winter weather was nuclear plants being knocked offline.
homie that's just me being autistic.
that's interesting, though i was speaking as an average throughout the whole day. Could very well still be true though.
yeah idk about that one chief i mean, you can clearly see it's combined cycle gas causing the problem primarily, there's also a bit of drop in gas, and it appears other sources also do, but that appears to be a graphing artifact more than anything.
It was literally reported that gas plants couldn't fire due to the pipes being frozen, while nuclear may have contributed, i believe the plants in question were already shutdown for maintenance or non operation to begin with. Also compounded with the grid being excessively depended on, due to electric resistive heating.
https://energy.utexas.edu/sites/default/files/UTAustin%20%282021%29%20EventsFebruary2021TexasBlackout%2020210714.pdf
in fact scrolling through an investigation in what happened it appears about 1300 MW of nuclear went offline, which is the collectively equivalent of, one plant. And it looks like it was an automated shutdown, which should've been expected.
In fact, considerably more coal, gas, wind power died out. The only thing less significant was solar power.
And if we go forward in history just a year we can find an example of similar grid mismanagement, though this time it was during the summer and due to improper grid configuration, nearing a potential grid outage. And with solar instead of gas.