4 ms·

The thing is, 183GW from PV is like 20-30GW of nuclear, because nuclear's capacity factor is near 100% and PV's is often near 10%. Storage seems hard and expen

by mlyle 4y ago

The thing is, 183GW from PV is like 20-30GW of nuclear, because nuclear's capacity factor is near 100% and PV's is often near 10%. Storage seems hard and expensive. We're going to need a whole lot of approaches: - Wind taking a bigger share of renewables - Whatever storage we can reasonably build, including some exotic stuff like power-to-gas-to-power. - Nuclear filling in a little bit - PV comically overbuilt and routinely throwing away a lot of power midday on most days. - Still peaking off natural gas, a little bit.

ncmncm 4y ago
Renewables' capacity factor is much greater than 10%, in practice. If you need falsehoods to make your case, you have no case.
- mlyle 4y ago
  > > The thing is, 183GW from PV is like 20-30GW of nuclear, because nuclear's capacity factor is near 100% and PV's is often near 10%. > Renewables' capacity factor is much greater than 10%, in practice. If you need falsehoods to make your case, you have no case. Residential/commercial PV -- e.g. rooftop solar-- very often is 10% or less. If you want to only look at utility-scale fixed tilt, instead, recent deployments average near (not quite) 20%. https://emp.lbl.gov/pv-capacity-factors https://emp.lbl.gov/pv-capacity-factors Nuclear's capacity factor is 93%. In which case, 183GW from utility-scale, fixed-tilt PV is like 183/.93 * .20 = 39GW. Which, admittedly, is outside of my range of 20-30, but also relies on generous assumptions (utility scale projects only-- which are only ~25% of US solar wattage). If you consider only tracking, you can get all the way to 49GW, which still doesn't eliminate the point. Perhaps the bigger point is looking at the eastern seaboard. Shipping power 2000 miles is not super practical for various reasons, and the capacity factors for a whole region of the US are pretty poor.
  - r00fus 4y ago
    How much solar capacity is actually residential? I'd say quite small since solar is hard to deploy residential + lack of home value improvement. Nuclear should be part of the equation (it has it's own issues with wastewater) but if adding nuclear means not investing equally or more in solar/wind renewables, that's completely misguided.
    - mlyle 4y ago
      > How much solar capacity is actually residential? I'm not sure how much is residential, but about 25% is utility-scale projects. The rest is stuff on commercial buildings and homes-- which have an average capacity factor around 12%. > Nuclear should be part of the equation (it has it's own issues with wastewater) but if adding nuclear means not investing equally or more in solar/wind renewables, that's completely misguided. I totally agree. I think our priorities should be, in order: - Wind - Pumped storage - Improved utility interties - Demand-side management - PV - Nuclear - Battery storage - Electrolyzers, etc But even the lowest priority item should be aggressively pursued.
      - pfdietz 4y ago
        Utility scale solar is greater than small scale (< 1 MW) solar in the US, and this is disparity is projected to increase through 2050. This is good, because utility scale solar is cheaper per unit output than small scale solar. https://www.eia.gov/todayinenergy/detail.php?id=50357 https://www.eia.gov/todayinenergy/detail.php?id=50357
        mlyle 4y ago
        > Utility scale solar is greater than small scale (< 1 MW) solar in the US Your graph shows in total generated energy per year it's roughly even--- not in nameplate power. Because the capacity factor is worse, you need a lot more nameplate power at non-utility installations to get the same energy out. > This is good, because utility scale solar is cheaper per unit output than small scale solar. Yup. Small scale solar really needs to stop, other than for installations that have special requirements (e.g. need for power backup / diversity).
        ncmncm 4y ago
        You would forbid me to buy panels?
        mlyle 4y ago
  - ncmncm 4y ago
    Shipping power 2000 miles is absolutely super-practical. China has a project to send it 8000 miles from solar farms they are building in Chile, for use during nighttime in China.
    - mlyle 4y ago
      > Shipping power 2000 miles is absolutely super-practical. DC interconnect makes it more practical, and it's better than storage, but losses and costs accumulate. > China has a project to send it 8000 miles from solar farms they are building in Chile Chile has proposed a project to do just that. It is in exceptionally early conceptual planning stages-- but look at you acting like it's a fait accompli!
      - ncmncm 4y ago
        Chile does not drive massive energy projects. China is in the driver seat. I doubt it will end up built, but that will not be because it is impractical. It will be because local generation and storage will turn out to be cheaper and less vulnerable to geopolitical upset.
        ben_w 4y ago
        Last time I looked at this, antipodal HVDC was several (2? 3? Can't remember) orders of magnitude cheaper than batteries at the scale of continental electrical requirements; the limit is needing so much metal you become a dominant player in the world metal mining industry just for this project.
        ncmncm 4y ago
        Batteries are the most expensive storage. A negligible fraction of utility storage will be batteries unless some new battery chemistry is very, very cheap. Almost all current utility storage is gravity. That probably won't change.
        ben_w 4y ago
  - ncmncm 4y ago
    Nukes' utility factor will fall rapidly as renewables and storage undercut them. Each decrease in utility factor multiplies their per-kWh cost, making them increasingly uncompetitive, and that at a steadily increasing rate. Nukes will shortly be mothballed, to perhaps be fired up once in a while in response to spiking demand.
    - mlyle 4y ago
      You continually do this: reply to the same comments multiple times from different angles hours apart; make unsupported assertions that storage will fix everything, etc. It doesn't lead to productive conversation.
ben_w 4y ago
Even at 10% capacity factor, and with a sudden cessation of the long term exponential trend in PV, and assuming the 2021 numbers for new nuclear power while ignoring that more was shut down, that still leaves more than twice as much new PV as new nuclear.
- mlyle 4y ago
  Sure, but I think we already know that we build a lot more PV than nuclear. The question is, should we build a bit more nuclear? Even a small change would be equivalent to a lot of PV production, and provide power at times when PV can't.
  - ben_w 4y ago
    Well on that point I agree completely, although mainly because I think it's a good idea to have a diversity of supply and not because it's the most cost effective. From what I've seen, the cheapest solution is a few square meters' cross section of HVDC encircling the planet, but that would almost certainly take a big increase in global metal mining even on these time scales and even when ignoring the political issues.
aidenn0 4y ago
For the USA, utility scale PV runs at a capacity factor of over 25% in the sunbelt and mid teens elsewhere. I suppose that may qualify as "often near 10%" but I think you are overstating it a bit, as really household PV is the only one that really is around 10%.
- mlyle 4y ago
  See https://news.ycombinator.com/item?id=31755603 https://news.ycombinator.com/item?id=31755603 Note non-utility scale solar is 75% of the installed watts, too-- so you have a huge share of it pulling towards that 10-12% number.
r00fus 4y ago
PV throwing off excess during peak is fine - if we have storage. Storage is has only recently become feasible, it would likely be utility-grade storage, Powerwall/home storage or Vehicle2Grid integration by the 2050 timeframe. Storage cost being excessive means it's early adoption timeframe. As the need for it becomes clear options will open up.
- mlyle 4y ago
  > PV throwing off excess during peak is fine PV throwing off excess during peak is fine even if we don't have storage, because it means PV is adequate for a bigger fraction of the morning and evening (and in turn, the needs for storage become a little less because of the over-provisioning of production).
- ncmncm 4y ago
  Storage is cheap and getting cheaper even faster than solar. Batteries will only ever be a tiny fraction of storage.

by mlyle 4y ago

ncmncm 4y ago

Renewables' capacity factor is much greater than 10%, in practice. If you need falsehoods to make your case, you have no case.

mlyle 4y ago
> > The thing is, 183GW from PV is like 20-30GW of nuclear, because nuclear's capacity factor is near 100% and PV's is often near 10%. > Renewables' capacity factor is much greater than 10%, in practice. If you need falsehoods to make your case, you have no case. Residential/commercial PV -- e.g. rooftop solar-- very often is 10% or less. If you want to only look at utility-scale fixed tilt, instead, recent deployments average near (not quite) 20%. https://emp.lbl.gov/pv-capacity-factors https://emp.lbl.gov/pv-capacity-factors Nuclear's capacity factor is 93%. In which case, 183GW from utility-scale, fixed-tilt PV is like 183/.93 * .20 = 39GW. Which, admittedly, is outside of my range of 20-30, but also relies on generous assumptions (utility scale projects only-- which are only ~25% of US solar wattage). If you consider only tracking, you can get all the way to 49GW, which still doesn't eliminate the point. Perhaps the bigger point is looking at the eastern seaboard. Shipping power 2000 miles is not super practical for various reasons, and the capacity factors for a whole region of the US are pretty poor.
- r00fus 4y ago
  How much solar capacity is actually residential? I'd say quite small since solar is hard to deploy residential + lack of home value improvement. Nuclear should be part of the equation (it has it's own issues with wastewater) but if adding nuclear means not investing equally or more in solar/wind renewables, that's completely misguided.
  - mlyle 4y ago
    > How much solar capacity is actually residential? I'm not sure how much is residential, but about 25% is utility-scale projects. The rest is stuff on commercial buildings and homes-- which have an average capacity factor around 12%. > Nuclear should be part of the equation (it has it's own issues with wastewater) but if adding nuclear means not investing equally or more in solar/wind renewables, that's completely misguided. I totally agree. I think our priorities should be, in order: - Wind - Pumped storage - Improved utility interties - Demand-side management - PV - Nuclear - Battery storage - Electrolyzers, etc But even the lowest priority item should be aggressively pursued.
    - pfdietz 4y ago
      Utility scale solar is greater than small scale (< 1 MW) solar in the US, and this is disparity is projected to increase through 2050. This is good, because utility scale solar is cheaper per unit output than small scale solar. https://www.eia.gov/todayinenergy/detail.php?id=50357 https://www.eia.gov/todayinenergy/detail.php?id=50357
      - mlyle 4y ago
        > Utility scale solar is greater than small scale (< 1 MW) solar in the US Your graph shows in total generated energy per year it's roughly even--- not in nameplate power. Because the capacity factor is worse, you need a lot more nameplate power at non-utility installations to get the same energy out. > This is good, because utility scale solar is cheaper per unit output than small scale solar. Yup. Small scale solar really needs to stop, other than for installations that have special requirements (e.g. need for power backup / diversity).
        ncmncm 4y ago
        You would forbid me to buy panels?
        mlyle 4y ago
- ncmncm 4y ago
  Shipping power 2000 miles is absolutely super-practical. China has a project to send it 8000 miles from solar farms they are building in Chile, for use during nighttime in China.
  - mlyle 4y ago
    > Shipping power 2000 miles is absolutely super-practical. DC interconnect makes it more practical, and it's better than storage, but losses and costs accumulate. > China has a project to send it 8000 miles from solar farms they are building in Chile Chile has proposed a project to do just that. It is in exceptionally early conceptual planning stages-- but look at you acting like it's a fait accompli!
    - ncmncm 4y ago
      Chile does not drive massive energy projects. China is in the driver seat. I doubt it will end up built, but that will not be because it is impractical. It will be because local generation and storage will turn out to be cheaper and less vulnerable to geopolitical upset.
      - ben_w 4y ago
        Last time I looked at this, antipodal HVDC was several (2? 3? Can't remember) orders of magnitude cheaper than batteries at the scale of continental electrical requirements; the limit is needing so much metal you become a dominant player in the world metal mining industry just for this project.
        ncmncm 4y ago
        Batteries are the most expensive storage. A negligible fraction of utility storage will be batteries unless some new battery chemistry is very, very cheap. Almost all current utility storage is gravity. That probably won't change.
        ben_w 4y ago
- ncmncm 4y ago
  Nukes' utility factor will fall rapidly as renewables and storage undercut them. Each decrease in utility factor multiplies their per-kWh cost, making them increasingly uncompetitive, and that at a steadily increasing rate. Nukes will shortly be mothballed, to perhaps be fired up once in a while in response to spiking demand.
  - mlyle 4y ago
    You continually do this: reply to the same comments multiple times from different angles hours apart; make unsupported assertions that storage will fix everything, etc. It doesn't lead to productive conversation.

ben_w 4y ago

Even at 10% capacity factor, and with a sudden cessation of the long term exponential trend in PV, and assuming the 2021 numbers for new nuclear power while ignoring that more was shut down, that still leaves more than twice as much new PV as new nuclear.

mlyle 4y ago
Sure, but I think we already know that we build a lot more PV than nuclear. The question is, should we build a bit more nuclear? Even a small change would be equivalent to a lot of PV production, and provide power at times when PV can't.
- ben_w 4y ago
  Well on that point I agree completely, although mainly because I think it's a good idea to have a diversity of supply and not because it's the most cost effective. From what I've seen, the cheapest solution is a few square meters' cross section of HVDC encircling the planet, but that would almost certainly take a big increase in global metal mining even on these time scales and even when ignoring the political issues.

aidenn0 4y ago

For the USA, utility scale PV runs at a capacity factor of over 25% in the sunbelt and mid teens elsewhere. I suppose that may qualify as "often near 10%" but I think you are overstating it a bit, as really household PV is the only one that really is around 10%.

mlyle 4y ago
See https://news.ycombinator.com/item?id=31755603 https://news.ycombinator.com/item?id=31755603 Note non-utility scale solar is 75% of the installed watts, too-- so you have a huge share of it pulling towards that 10-12% number.

r00fus 4y ago

PV throwing off excess during peak is fine - if we have storage. Storage is has only recently become feasible, it would likely be utility-grade storage, Powerwall/home storage or Vehicle2Grid integration by the 2050 timeframe. Storage cost being excessive means it's early adoption timeframe. As the need for it becomes clear options will open up.

mlyle 4y ago
> PV throwing off excess during peak is fine PV throwing off excess during peak is fine even if we don't have storage, because it means PV is adequate for a bigger fraction of the morning and evening (and in turn, the needs for storage become a little less because of the over-provisioning of production).
ncmncm 4y ago
Storage is cheap and getting cheaper even faster than solar. Batteries will only ever be a tiny fraction of storage.