3 ms·

I listened to a whole Joe Rogan podcast where a guest kept advocating for using nuclear to balance out the intermittent nature of solar and wind. I could never

I listened to a whole Joe Rogan podcast where a guest kept advocating for using nuclear to balance out the intermittent nature of solar and wind. I could never wrap my mind around how this makes sense. Nuclear has a fixed output, it doesn’t scale up and down the way fossil fuel plants do. If your nuclear capacity can cover the worst case where solar and wind aren’t producing, it can cover all cases, and the solar and wind become irrelevant. Seems like the linked concept is similarly making something more complicated in the hopes that somehow makes it better. Like bundling subprime mortgages.

robertlagrant 3y ago
It's definitely not perfect, but e.g. with pumped hydro, you can run it in peak hours when demand exceeds baseline supply.
2OEH8eoCRo0 3y ago
> Nuclear has a fixed output A fixed thermal output or a fixed electrical output?
idiotsecant 3y ago
That's exactly what you want for easy control of grid stability. Say you typically fluctuate between 100 and 150 GW of demand. You turn on 80GW of nuke, leave it running all the time, and then as resources come available from intermittent sources those can contribute to total load requirements. If you have a wide enough diversity of intermittent sources this works well. The problem with intermittent generation sources is that you must either store energy or overprovision generation to make up for the gaps in availability (or make wildly expensive transmission improvements but that is another discussion). For reasons of expense and reliability you must make a tradeoff between how much of your generation is reliable baseload and how much is intermittent generation. Nuke + intermittent sources is a very good match.
- eppp 3y ago
  You could also add time of use pricing to encourage use during peak renewable generation.
  - Scoundreller 3y ago
    My jurisdiction rolled out millions of Time of Use smart meters only to find that residential users really didn’t change their behaviour much. Demand shifting was something like a couple percent and faaaar less than predicted. It turns out when you run surveys, it’s the people that like to think about answers to questions that respond to them, which isn’t representative. 45pg pdf government report: https://www.auditor.on.ca/en/content/annualreports/arreports/en14/311en14.pdf https://www.auditor.on.ca/en/content/annualreports/arreports... which starts getting good at page 5. Understated costs and exaggerated benefits. Peak reduction targets ended up with increases in peak demand. As hard as it is for the HNer to believe, the vast majority of people will just do whatever they want whenever they want. I see this everywhere: “why would anyone go to this expensive supermarket that sells the same crap as the cheap one I go to? Why would anyone go to that gas station, their price is always higher than the others in the surrounding area. Why would anyone buy that car, it has a terrible TCO, and on and on”
    - knutzui 3y ago
      ToU pricing can be very effectively used by having an energy management system. This will automatically shift power usage to the most cost efficient times.
      - Scoundreller 3y ago
        In theory. After 15 years, the best most of us in Ontario have is a “4h delay” on a dishwasher and discounted (not free) smart thermostats that you have to install yourself or pay an installer for. I suppose electric cars do a good job here at least. And this is in new construction. Overall, it didn’t (and may never) make financial sense to put light users on smart/time of day metering.
    - toast0 3y ago
datadrivenangel 3y ago
Modern nuclear plants can scale much more aggressively than older plants. This is also true of coal plants as well. Still not perfect to have them be load following resources though.
toast0 3y ago
> I could never wrap my mind around how this makes sense. Nuclear has a fixed output, it doesn’t scale up and down the way fossil fuel plants do. Nuclear can and does regulate its output. And the fuel rods should last longer if you run at less than full output. But fuel cost is not a large component of nuclear energy cost, so it doesn't make a lot of economic sense to operate them far above or below their steady state maximum capacity. I agree that nuclear doesn't make a good backfill for intermittant sources; but it's not because they can't, it's because the economics aren't good.
- pbmonster 3y ago
  > Nuclear can and does regulate its output. They do in France. You kind of have to, if you produce 70% of your power in nuke plants. But in the US, it's not done in any meaningful sense. All US plants run at 100% capacity all the time. The reason for that is that it's incredibly complicated to ramp a nuke plant. If you take a reactor and reduce its heat output significantly, the currently active volume of fuel moves away from the decay product equilibrium - the reactor poisons its own fuel rods with neutron absorbing decay products. This makes a subsequent increase in output power extremely dangerous and thus impossible in practice. The only way to increase power safely is to wait for the radio poison to decay naturally, which can takes tens of days (and depends on by how much you reduced power). The only reason the French can ramp the power of their nuclear plants up and down is that they have so many of them, and they are all controlled by a central authority. This means the reactors can take turns in reducing power, each night a different set of reactors poison their fuel and recover slowly over the next week or two. There is also of course an economic side to this. In the US, nuclear power is so economically risky that planning a plant that is not trying as hard as it possibly can to recoup it's enormous investment would sound crazy to investors. It would make zero economic sense to not run at 100% all the time, and would probably make any newly build plant a billion dollar loss instantly.
arc-in-space 3y ago
>If your nuclear capacity can cover the worst case where solar and wind aren’t producing, it can cover all cases, and the solar and wind become irrelevant. This is plainly false; nation-wide energy consumption isn't fixed, it adapts to supply. Not all usage of energy is equally valuable, if the prices go up, you might choose to turn off your TV, but you'll probably keep your fridge running. With more energy, more activity can happen at lower prices.
gwbas1c 3y ago
> Nuclear has a fixed output, it doesn’t scale up and down the way fossil fuel plants do. This is a very, very old, and very, very solved problem. Today we'd solve it with batteries: Discharge when demand outstrips supply, recharge when supply outstrips demand. In the past, nuclear power was often paired with pumped storage: https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricit... Today a lot of pumped storage facilities have outlasted the nuclear power plants they were built to support. Instead of pumping at night, they pump when there's excess solar or wind.
mschuster91 3y ago
> Seems like the linked concept is similarly making something more complicated in the hopes that somehow makes it better. Because battery storage is legitimately better in terms of reaction time and efficiency: pumped hydro is 2 min from 0 to 100%, with a total efficiency ratio between .65-.85 [1], gas plants are at 3-5 minutes (peakers)/up to 30 min (combined power+heat) [2] and .35-.50 efficiency ratio (more if thermal energy is captured, but that only makes sense for non-peaker plants that also provide district heating)... whereas a battery plant's reaction time can be measured in milliseconds. That's orders of magnitude faster and is what makes decentralized battery storage worth it. [1] https://um.baden-wuerttemberg.de/de/energie/versorgungssicherheit/energiespeicher https://um.baden-wuerttemberg.de/de/energie/versorgungssiche... [2] https://www.ingenieur.de/fachmedien/bwk/erneuerbare-energien/gasmotoren-kraftwerke-in-kombination-mit-erneuerbaren-energien/ https://www.ingenieur.de/fachmedien/bwk/erneuerbare-energien... [3] https://www.deutschlandfunknova.de/nachrichten/australien-riesenakku-verhindert-stromausfall https://www.deutschlandfunknova.de/nachrichten/australien-ri...

robertlagrant 3y ago

It's definitely not perfect, but e.g. with pumped hydro, you can run it in peak hours when demand exceeds baseline supply.

2OEH8eoCRo0 3y ago

> Nuclear has a fixed output A fixed thermal output or a fixed electrical output?

idiotsecant 3y ago

That's exactly what you want for easy control of grid stability. Say you typically fluctuate between 100 and 150 GW of demand. You turn on 80GW of nuke, leave it running all the time, and then as resources come available from intermittent sources those can contribute to total load requirements. If you have a wide enough diversity of intermittent sources this works well. The problem with intermittent generation sources is that you must either store energy or overprovision generation to make up for the gaps in availability (or make wildly expensive transmission improvements but that is another discussion). For reasons of expense and reliability you must make a tradeoff between how much of your generation is reliable baseload and how much is intermittent generation. Nuke + intermittent sources is a very good match.

eppp 3y ago
You could also add time of use pricing to encourage use during peak renewable generation.
- Scoundreller 3y ago
  My jurisdiction rolled out millions of Time of Use smart meters only to find that residential users really didn’t change their behaviour much. Demand shifting was something like a couple percent and faaaar less than predicted. It turns out when you run surveys, it’s the people that like to think about answers to questions that respond to them, which isn’t representative. 45pg pdf government report: https://www.auditor.on.ca/en/content/annualreports/arreports/en14/311en14.pdf https://www.auditor.on.ca/en/content/annualreports/arreports... which starts getting good at page 5. Understated costs and exaggerated benefits. Peak reduction targets ended up with increases in peak demand. As hard as it is for the HNer to believe, the vast majority of people will just do whatever they want whenever they want. I see this everywhere: “why would anyone go to this expensive supermarket that sells the same crap as the cheap one I go to? Why would anyone go to that gas station, their price is always higher than the others in the surrounding area. Why would anyone buy that car, it has a terrible TCO, and on and on”
  - knutzui 3y ago
    ToU pricing can be very effectively used by having an energy management system. This will automatically shift power usage to the most cost efficient times.
    - Scoundreller 3y ago
      In theory. After 15 years, the best most of us in Ontario have is a “4h delay” on a dishwasher and discounted (not free) smart thermostats that you have to install yourself or pay an installer for. I suppose electric cars do a good job here at least. And this is in new construction. Overall, it didn’t (and may never) make financial sense to put light users on smart/time of day metering.
  - toast0 3y ago

datadrivenangel 3y ago

Modern nuclear plants can scale much more aggressively than older plants. This is also true of coal plants as well. Still not perfect to have them be load following resources though.

toast0 3y ago

> I could never wrap my mind around how this makes sense. Nuclear has a fixed output, it doesn’t scale up and down the way fossil fuel plants do. Nuclear can and does regulate its output. And the fuel rods should last longer if you run at less than full output. But fuel cost is not a large component of nuclear energy cost, so it doesn't make a lot of economic sense to operate them far above or below their steady state maximum capacity. I agree that nuclear doesn't make a good backfill for intermittant sources; but it's not because they can't, it's because the economics aren't good.

pbmonster 3y ago
> Nuclear can and does regulate its output. They do in France. You kind of have to, if you produce 70% of your power in nuke plants. But in the US, it's not done in any meaningful sense. All US plants run at 100% capacity all the time. The reason for that is that it's incredibly complicated to ramp a nuke plant. If you take a reactor and reduce its heat output significantly, the currently active volume of fuel moves away from the decay product equilibrium - the reactor poisons its own fuel rods with neutron absorbing decay products. This makes a subsequent increase in output power extremely dangerous and thus impossible in practice. The only way to increase power safely is to wait for the radio poison to decay naturally, which can takes tens of days (and depends on by how much you reduced power). The only reason the French can ramp the power of their nuclear plants up and down is that they have so many of them, and they are all controlled by a central authority. This means the reactors can take turns in reducing power, each night a different set of reactors poison their fuel and recover slowly over the next week or two. There is also of course an economic side to this. In the US, nuclear power is so economically risky that planning a plant that is not trying as hard as it possibly can to recoup it's enormous investment would sound crazy to investors. It would make zero economic sense to not run at 100% all the time, and would probably make any newly build plant a billion dollar loss instantly.

arc-in-space 3y ago

>If your nuclear capacity can cover the worst case where solar and wind aren’t producing, it can cover all cases, and the solar and wind become irrelevant. This is plainly false; nation-wide energy consumption isn't fixed, it adapts to supply. Not all usage of energy is equally valuable, if the prices go up, you might choose to turn off your TV, but you'll probably keep your fridge running. With more energy, more activity can happen at lower prices.

gwbas1c 3y ago

> Nuclear has a fixed output, it doesn’t scale up and down the way fossil fuel plants do. This is a very, very old, and very, very solved problem. Today we'd solve it with batteries: Discharge when demand outstrips supply, recharge when supply outstrips demand. In the past, nuclear power was often paired with pumped storage: https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricit... Today a lot of pumped storage facilities have outlasted the nuclear power plants they were built to support. Instead of pumping at night, they pump when there's excess solar or wind.

mschuster91 3y ago

> Seems like the linked concept is similarly making something more complicated in the hopes that somehow makes it better. Because battery storage is legitimately better in terms of reaction time and efficiency: pumped hydro is 2 min from 0 to 100%, with a total efficiency ratio between .65-.85 [1], gas plants are at 3-5 minutes (peakers)/up to 30 min (combined power+heat) [2] and .35-.50 efficiency ratio (more if thermal energy is captured, but that only makes sense for non-peaker plants that also provide district heating)... whereas a battery plant's reaction time can be measured in milliseconds. That's orders of magnitude faster and is what makes decentralized battery storage worth it. [1] https://um.baden-wuerttemberg.de/de/energie/versorgungssicherheit/energiespeicher https://um.baden-wuerttemberg.de/de/energie/versorgungssiche... [2] https://www.ingenieur.de/fachmedien/bwk/erneuerbare-energien/gasmotoren-kraftwerke-in-kombination-mit-erneuerbaren-energien/ https://www.ingenieur.de/fachmedien/bwk/erneuerbare-energien... [3] https://www.deutschlandfunknova.de/nachrichten/australien-riesenakku-verhindert-stromausfall https://www.deutschlandfunknova.de/nachrichten/australien-ri...