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In the US, PV solar capacity factor is about 0.24 (partly because lots of people live near very sunny regions like California and Texas). The National Renewable

In the US, PV solar capacity factor is about 0.24 (partly because lots of people live near very sunny regions like California and Texas). The National Renewable Energy Laboratory claims that in some parts of the US utility-scale solar capacity factors are 0.33 [0]. Wind is about 0.36, Hydro also 0.36, Nuclear about 0.93 [1]. If you apply these capacity factors to the nameplate capacities (ignoring batteries), you get 58.5% solar, 19.7% wind, 15.1% natural gas, and 6.6% nuclear. [0]: https://atb.nrel.gov/electricity/2021/utility-scale_pv https://atb.nrel.gov/electricity/2021/utility-scale_pv [1]: https://www.eia.gov/electricity/monthly/epm_table_grapher.php?t=epmt_6_07_b https://www.eia.gov/electricity/monthly/epm_table_grapher.ph...

Retric 3y ago
US nuclear averages below 0.9, individual plants can break 0.93 for a single year, but long term maintenance and refueling cycles lower the average. Ex: 95.73% (2017) 80.25% (lifetime) https://en.wikipedia.org/wiki/Beaver_Valley_Nuclear_Power_Station https://en.wikipedia.org/wiki/Beaver_Valley_Nuclear_Power_St... 94.43% (2017) 75.20% (lifetime) https://en.wikipedia.org/wiki/Brunswick_Nuclear_Generating_Station https://en.wikipedia.org/wiki/Brunswick_Nuclear_Generating_S... 96.04% (2017) 78.07% (lifetime) https://en.wikipedia.org/wiki/Browns_Ferry_Nuclear_Plant https://en.wikipedia.org/wiki/Browns_Ferry_Nuclear_Plant So you can cherry pick a few numbers from the best years, but the lifetime averages tell a different story.
- foota 3y ago
  Is a 15% difference that much of a different story?
  - hef19898 3y ago
    Look at your paycheck, and imagine the number is 15% lower. Should answer the question.
    - deleted 3y ago
      [deleted]
    - blackoil 3y ago
      If alternate pay is 90% lower, not big of a difference. i.e. If I lose job, I would prefer new one to pay 85% than 10%.
    - foota 3y ago
      It does. And no, it's not that significant. I'm not a nuclear fanboy (well, I wish I made sense since I like the idea of free energy, but renewables are just as good), but I think it's important to make accurate arguments.
      - hef19898 3y ago
        An accurate argument would include the financial aspects of +/- 15% in generated output and the impact that has on grid capacity....
        deleted 3y ago
        [deleted]
        deleted 3y ago
        [deleted]
        foota 3y ago
        With such a small difference, the burden of proof in this case is probably on the person arguing that it is a big difference, since you'd generally expect a roughly linear relationship between these. In fact, I think I'd suspect that downtime is less relevant for nuclear, since I believe most of it will be schedulable, as opposed to renewables where downtime is random and based on conditions. Since it's schedulable, it could be done in the off season, or different plants could be planned to be out at difference periods.
        hef19898 3y ago
        You actually have no idea about electricity transmission. For long term problems, look no further than France. Short term, look up how electricity generation, transmission, markets and grid stability are linked. Wikipedia is a good start. Followed by studies about 100% renewable grids, those explain why baseload is much less of an issue than people think. And too much inflexible capacity, aka baseload, can actually be a problem itself.
- throwaway87651 3y ago
  Nuclear had much lower capacity factors in the past, which brings the lifetime capacity factor down. But the relevant point is that the capacity factor of nuclear plants running today is >90%
  - Retric 3y ago
    US Nuclear had a capacity factor of 86.1% as recently as 2012, it just varies through time and over a 40+ year lifetime you don’t have outstanding results every single year. So sure you can argue 71.1% in 1997 no longer applies, but it was almost exactly the same fleet of reactors in use back then. Yet the person I was replying to said “about 93%” when averaging over 93% has been achieved exactly once in 2019. That kind of nonsense is actively harmful when people hear something and then later realize it’s simply incorrect. Effective advocacy requires accuracy including technology specific issues and how to mitigate them.
    - looofooo0 3y ago
      Planned or unplanned is the question.
      - Retric 3y ago
        The larger question is what capacity factors would look like if you tried to double the amount of nuclear as many advocates wish. And what that would do to profitability / the need for subsidies. Or as the industry has been concerned with for a decade, what happens when renewable energy is regularly sending wholesale prices near zero for hours a day.
Maakuth 3y ago
Of course those capacity factors hide one important bit, the dispatchability. While the capacity factor is the same in this list for wind and hydro, the wind and solar generation are naturally capped by nature. When demand exceeds the natural availability of these, you need to dispatch some extra generation. Hydro and natural gas are well suited for this, coal can do it even if dirtily. Nuclear generation could be made dispatchable, but due to the essentially zero marginal cost of running it all the time instead of limiting generation, it seldom is used in this fashion. Electricity demand could be elastic too, but there's a limit to that. It's not always feasible to limit or shut down industrial processes for the few hours of expensive power. And home consumers are loath to not use their stoves when they want. There's potential in elastic demand though.
- hef19898 3y ago
  Take a close look at the title again, second word after "solar", you have to pass by "and" to get there.
  - Maakuth 3y ago
    I guess I earned the snark for not mentioning the batteries. Weirdly the news item doesn't tell what sort of energy storage capacity these battery installation have, only the peak power output of 14.3 GW for this year's addition. While that is certainly a gigantic addition no matter what the energy capacity of these battery installations is going to be, running the whole grid on batteries over the periods of low renewable generation is going to require still orders of magnitude more batteries. I suppose there's enough lithium in the ground for this, but elastic demand and dispatchable generation are probably going to be part of the equation for economical reasons.
    - randunel 3y ago
      Plenty of batteries in the US are built out of water. They pump the water up during the day and it generates electricity at night. No lithium involved. > Pumped storage is by far the largest-capacity form of grid energy storage available, and, as of 2020, the United States Department of Energy Global Energy Storage Database reports that PSH accounts for around 95% of all active tracked storage installations worldwide, with a total installed throughput capacity of over 181 GW, of which about 29 GW are in the United States, and a total installed storage capacity of over 1.6 TWh, of which about 250 GWh are in the United States. I recently visited this one https://en.m.wikipedia.org/wiki/Gianelli_Power_Plant https://en.m.wikipedia.org/wiki/Gianelli_Power_Plant
ianai 3y ago
This discussion makes me realize we could have a 100% renewable energy grid and discussion will still be pushed with the same old “arguments” against renewable being feasible. Ridiculous.
dfc 3y ago
I do not understand your math. How did you go from .36 for wind, apply it to nameplate capacity and get 15.1%? And percent of what? I thought applying the capacity factor to nameplate would result in some measure of energy produced, not a percentage.

Retric 3y ago

US nuclear averages below 0.9, individual plants can break 0.93 for a single year, but long term maintenance and refueling cycles lower the average. Ex: 95.73% (2017) 80.25% (lifetime) https://en.wikipedia.org/wiki/Beaver_Valley_Nuclear_Power_Station https://en.wikipedia.org/wiki/Beaver_Valley_Nuclear_Power_St... 94.43% (2017) 75.20% (lifetime) https://en.wikipedia.org/wiki/Brunswick_Nuclear_Generating_Station https://en.wikipedia.org/wiki/Brunswick_Nuclear_Generating_S... 96.04% (2017) 78.07% (lifetime) https://en.wikipedia.org/wiki/Browns_Ferry_Nuclear_Plant https://en.wikipedia.org/wiki/Browns_Ferry_Nuclear_Plant So you can cherry pick a few numbers from the best years, but the lifetime averages tell a different story.

foota 3y ago
Is a 15% difference that much of a different story?
- hef19898 3y ago
  Look at your paycheck, and imagine the number is 15% lower. Should answer the question.
  - deleted 3y ago
    [deleted]
  - blackoil 3y ago
    If alternate pay is 90% lower, not big of a difference. i.e. If I lose job, I would prefer new one to pay 85% than 10%.
  - foota 3y ago
    It does. And no, it's not that significant. I'm not a nuclear fanboy (well, I wish I made sense since I like the idea of free energy, but renewables are just as good), but I think it's important to make accurate arguments.
    - hef19898 3y ago
      An accurate argument would include the financial aspects of +/- 15% in generated output and the impact that has on grid capacity....
      - deleted 3y ago
        [deleted]
      - deleted 3y ago
        [deleted]
      - foota 3y ago
        With such a small difference, the burden of proof in this case is probably on the person arguing that it is a big difference, since you'd generally expect a roughly linear relationship between these. In fact, I think I'd suspect that downtime is less relevant for nuclear, since I believe most of it will be schedulable, as opposed to renewables where downtime is random and based on conditions. Since it's schedulable, it could be done in the off season, or different plants could be planned to be out at difference periods.
        hef19898 3y ago
        You actually have no idea about electricity transmission. For long term problems, look no further than France. Short term, look up how electricity generation, transmission, markets and grid stability are linked. Wikipedia is a good start. Followed by studies about 100% renewable grids, those explain why baseload is much less of an issue than people think. And too much inflexible capacity, aka baseload, can actually be a problem itself.
throwaway87651 3y ago
Nuclear had much lower capacity factors in the past, which brings the lifetime capacity factor down. But the relevant point is that the capacity factor of nuclear plants running today is >90%
- Retric 3y ago
  US Nuclear had a capacity factor of 86.1% as recently as 2012, it just varies through time and over a 40+ year lifetime you don’t have outstanding results every single year. So sure you can argue 71.1% in 1997 no longer applies, but it was almost exactly the same fleet of reactors in use back then. Yet the person I was replying to said “about 93%” when averaging over 93% has been achieved exactly once in 2019. That kind of nonsense is actively harmful when people hear something and then later realize it’s simply incorrect. Effective advocacy requires accuracy including technology specific issues and how to mitigate them.
  - looofooo0 3y ago
    Planned or unplanned is the question.
    - Retric 3y ago
      The larger question is what capacity factors would look like if you tried to double the amount of nuclear as many advocates wish. And what that would do to profitability / the need for subsidies. Or as the industry has been concerned with for a decade, what happens when renewable energy is regularly sending wholesale prices near zero for hours a day.

Maakuth 3y ago

Of course those capacity factors hide one important bit, the dispatchability. While the capacity factor is the same in this list for wind and hydro, the wind and solar generation are naturally capped by nature. When demand exceeds the natural availability of these, you need to dispatch some extra generation. Hydro and natural gas are well suited for this, coal can do it even if dirtily. Nuclear generation could be made dispatchable, but due to the essentially zero marginal cost of running it all the time instead of limiting generation, it seldom is used in this fashion. Electricity demand could be elastic too, but there's a limit to that. It's not always feasible to limit or shut down industrial processes for the few hours of expensive power. And home consumers are loath to not use their stoves when they want. There's potential in elastic demand though.

hef19898 3y ago
Take a close look at the title again, second word after "solar", you have to pass by "and" to get there.
- Maakuth 3y ago
  I guess I earned the snark for not mentioning the batteries. Weirdly the news item doesn't tell what sort of energy storage capacity these battery installation have, only the peak power output of 14.3 GW for this year's addition. While that is certainly a gigantic addition no matter what the energy capacity of these battery installations is going to be, running the whole grid on batteries over the periods of low renewable generation is going to require still orders of magnitude more batteries. I suppose there's enough lithium in the ground for this, but elastic demand and dispatchable generation are probably going to be part of the equation for economical reasons.
  - randunel 3y ago
    Plenty of batteries in the US are built out of water. They pump the water up during the day and it generates electricity at night. No lithium involved. > Pumped storage is by far the largest-capacity form of grid energy storage available, and, as of 2020, the United States Department of Energy Global Energy Storage Database reports that PSH accounts for around 95% of all active tracked storage installations worldwide, with a total installed throughput capacity of over 181 GW, of which about 29 GW are in the United States, and a total installed storage capacity of over 1.6 TWh, of which about 250 GWh are in the United States. I recently visited this one https://en.m.wikipedia.org/wiki/Gianelli_Power_Plant https://en.m.wikipedia.org/wiki/Gianelli_Power_Plant

ianai 3y ago

This discussion makes me realize we could have a 100% renewable energy grid and discussion will still be pushed with the same old “arguments” against renewable being feasible. Ridiculous.

dfc 3y ago

I do not understand your math. How did you go from .36 for wind, apply it to nameplate capacity and get 15.1%? And percent of what? I thought applying the capacity factor to nameplate would result in some measure of energy produced, not a percentage.