6 ms·

Gigawatts of capacity, I assume? What's the capacity factor of their investments, I wonder? E.g. how many GW-years of electricity do they generate in a year on

Gigawatts of capacity, I assume? What's the capacity factor of their investments, I wonder? E.g. how many GW-years of electricity do they generate in a year on average? It's much more important these days to measure progress is integral terms like low-carbon energy generated/year rather than max low-carbon power when in ideal conditions. It's even better to measure with things like lifecycle mass CO2-equiv/kWh avoided, which avoids traps of crediting things like forest combustion as "green" like drax does in the UK.

ericpauley 4y ago
This is so often under appreciated. For reference, non-FF capacity factors here: 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... So you’re probably looking at a 2-3x difference between renewable nameplate capacity and the equivalent replaced fossil fuels.
- jacquesm 4y ago
  Fossil also has downtime, as does nuclear. It just isn't as frequent. But in some cases (reactor shutdown for instance) it can be much more sudden and long than the way wind and solar vary. And prediction of near future solar/wind availability is getting better all the time helping a lot in dealing with the variability.
  - acidburnNSA 4y ago
    Average is what matters here when you're on the grid. Nuclear capacity factor averages 92% in the US. Solar averages 25%. Wind 35.
    - jacquesm 4y ago
      I've been 100% off grid for two consecutive years in Northern Canada. We did have a backup generator but it wasn't used after the windmill went up. 48 KWh of storage was enough to tide us over any period without sun/wind.
      - aeyes 4y ago
        What kind of windmill do you have? I did some research to see if it would make sense as a homeowner and found it to be mostly not worth it. You shouldn't attach it directly to the building because wind speed near surfaces slows down significantly. So you need a large pole which will make maintenance very expensive. You usually can't attach the pole directly to the building either because it isn't rated for such high forces. Wind mills are also quite noisy so you probably want to have a huge amount of land to put it far away from the house. The power produced rises to the power of two with the diameter of the rotor and to the power of three with wind speed. This means that you want an installation which is both large and high.
        jacquesm 4y ago
        I built my own. 16' diameter, variable pitch, and silent as can be. The noise a windmill makes is closely related to the thickness of the trailing edge of the blades.
        coda_ 4y ago
        Have you done any write ups or posts on your build? Or do you have any suggestions of other posts about similar builds? Would love to learn more about what it takes to do this.
        jacquesm 4y ago
        Absolutely. Part II has the diagrams and pretty much everything else. If you build one let me know! https://jacquesmattheij.com/how-to-build-a-windmill/ https://jacquesmattheij.com/how-to-build-a-windmill/
    - ZeroGravitas 4y ago
      Why does it matter though? Are coal plants better because they have higher capacity factors? Are they cheaper to run? I mean obviously if you compare two coal plants that are otherwise identical, you'd assume the higher capacity leads to cheaper power and is therefore better. But once you are comparing coal to solar, its utterly meaningless out of context. Even in the near identical coal case, why not say "this one is cheaper" or some other measurement people actually care about?
      - dahfizz 4y ago
        Coal plants aren't "better", but they work when its dark and not windy. We need _something_ to fill that (rather large) niche.
brookst 4y ago
Can you elaborate? Are there significant differences in ratios of power produced to max power? Naively I would expect some scaling factor to apply in most cases, as regional and seasonal differences come out in the wash.
- acidburnNSA 4y ago
  Huge differences based on region and technology. In California solar PV may generate 30% of its max capacity in a year due to nights and clouds, whereas in Seattle it may be well below 20% due to no sun in winter. Wind averages 35% due to lulls. Nuclear is about 92% (has to shut down every 2 years to refuel). Hydro often is run around 40% (depends on water availability). So building 13.7 GW of nuclear capacity in a northern region could generate ~5x more clean energy per year than 13.7 GW of solar capacity. Not sure if Apple is investing in nuclear or not. (:
  - Retric 4y ago
    Nameplate capacity is so vastly cheaper with solar it more than offsets that difference in all but the worst locations. In Nevada you nuclear is means paying 10x as much to get a 90% capacity factor vs 30% for solar. So you build 3x as much solar and a ton of batteries and still cost less than nuclear while being able to follow the demand curve.
    - acidburnNSA 4y ago
      If you only look at LCOE and ignore backup, transmission, recycling at scale, etc then sure!
      - Retric 4y ago
        LCOE is vastly lower for battery backed solar, that’s why it’s so cheap. You also don’t need backup with batteries that’s the entire point. Individual nuclear power plants are single points of failure and go offline randomly. Nuclear needs redundancy to ensure a stable grid which further increases its costs. Transmission is again worse for nuclear because it’s so centralized. With solar you can locate it much closer to end users which cuts down on annual transmission losses.
edhelas 4y ago
Also it's mandatory to take care of the backup used when there is "no-wind/no-sun". You can have your electricity share coming from renewable that is increasing, if in the end you have 30-40 of gaz/coal as a backup to handle the time when renewable is not producing you'll no go way further. Example: Germany.
- sveme 4y ago
  Care to put some numbers on the no wind/no sun scenario? As an example, the share of renewables in Germany never dropped below 30% last year and that only happened a couple of days. Average renewable contribution was >50%.
  - aeyes 4y ago
    I imagine that this is only for the grid production? If I charge my car with solar at home it won't move the meter, energy consumed by households with solar might not show up in the statistics. In reality renewable contribution might be even higher, unless there is correction for this.
  - KptMarchewa 4y ago
    Wind in Poland right now works on 2% capacity factor. 152MW out of 7.72GW installed. There is solar now, so renewables are not so bad. However, at 5AM it was bad - wind was only on 5%, zero solar. https://i.imgur.com/LAJ2cKP.png https://i.imgur.com/LAJ2cKP.png
  - barney54 4y ago
    What is your source for this? I’m highly skeptical because it means there was never a time of low wind at night ir when it was cloudy. February 26th of last year sure looks like a lot less than 30% renewable. https://mobile.twitter.com/energybants/status/1497392463731908614 https://mobile.twitter.com/energybants/status/14973924637319...
    - sveme 4y ago
      There's also hydro (incl. imported from Norway) and biomass. Source for total renewable over time is here: https://www.zeit.de/wirtschaft/energiemonitor-deutschland-gaspreis-spritpreis-energieversorgung https://www.zeit.de/wirtschaft/energiemonitor-deutschland-ga... There might be spells during the day where this is less than 30%, but that's what short term storage would be there for. The nightmare scenario, often mentioned, is weeks of clouds and low winds, which does not seem to have occurred last year, at least. And even when it's cloudy you still have some solar. By the way, I'm not arguing that all is well and everything is solved, I just hate this juvenile argument of "but what if it's cloudy and there is no wind for weeks", because that does not happen often, especially not on a continent-wide grid with lots of offshore wind power in one of the windiest seas in the world.

ericpauley 4y ago

This is so often under appreciated. For reference, non-FF capacity factors here: 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... So you’re probably looking at a 2-3x difference between renewable nameplate capacity and the equivalent replaced fossil fuels.

jacquesm 4y ago
Fossil also has downtime, as does nuclear. It just isn't as frequent. But in some cases (reactor shutdown for instance) it can be much more sudden and long than the way wind and solar vary. And prediction of near future solar/wind availability is getting better all the time helping a lot in dealing with the variability.
- acidburnNSA 4y ago
  Average is what matters here when you're on the grid. Nuclear capacity factor averages 92% in the US. Solar averages 25%. Wind 35.
  - jacquesm 4y ago
    I've been 100% off grid for two consecutive years in Northern Canada. We did have a backup generator but it wasn't used after the windmill went up. 48 KWh of storage was enough to tide us over any period without sun/wind.
    - aeyes 4y ago
      What kind of windmill do you have? I did some research to see if it would make sense as a homeowner and found it to be mostly not worth it. You shouldn't attach it directly to the building because wind speed near surfaces slows down significantly. So you need a large pole which will make maintenance very expensive. You usually can't attach the pole directly to the building either because it isn't rated for such high forces. Wind mills are also quite noisy so you probably want to have a huge amount of land to put it far away from the house. The power produced rises to the power of two with the diameter of the rotor and to the power of three with wind speed. This means that you want an installation which is both large and high.
      - jacquesm 4y ago
        I built my own. 16' diameter, variable pitch, and silent as can be. The noise a windmill makes is closely related to the thickness of the trailing edge of the blades.
        coda_ 4y ago
        Have you done any write ups or posts on your build? Or do you have any suggestions of other posts about similar builds? Would love to learn more about what it takes to do this.
        jacquesm 4y ago
        Absolutely. Part II has the diagrams and pretty much everything else. If you build one let me know! https://jacquesmattheij.com/how-to-build-a-windmill/ https://jacquesmattheij.com/how-to-build-a-windmill/
  - ZeroGravitas 4y ago
    Why does it matter though? Are coal plants better because they have higher capacity factors? Are they cheaper to run? I mean obviously if you compare two coal plants that are otherwise identical, you'd assume the higher capacity leads to cheaper power and is therefore better. But once you are comparing coal to solar, its utterly meaningless out of context. Even in the near identical coal case, why not say "this one is cheaper" or some other measurement people actually care about?
    - dahfizz 4y ago
      Coal plants aren't "better", but they work when its dark and not windy. We need _something_ to fill that (rather large) niche.

brookst 4y ago

Can you elaborate? Are there significant differences in ratios of power produced to max power? Naively I would expect some scaling factor to apply in most cases, as regional and seasonal differences come out in the wash.

acidburnNSA 4y ago
Huge differences based on region and technology. In California solar PV may generate 30% of its max capacity in a year due to nights and clouds, whereas in Seattle it may be well below 20% due to no sun in winter. Wind averages 35% due to lulls. Nuclear is about 92% (has to shut down every 2 years to refuel). Hydro often is run around 40% (depends on water availability). So building 13.7 GW of nuclear capacity in a northern region could generate ~5x more clean energy per year than 13.7 GW of solar capacity. Not sure if Apple is investing in nuclear or not. (:
- Retric 4y ago
  Nameplate capacity is so vastly cheaper with solar it more than offsets that difference in all but the worst locations. In Nevada you nuclear is means paying 10x as much to get a 90% capacity factor vs 30% for solar. So you build 3x as much solar and a ton of batteries and still cost less than nuclear while being able to follow the demand curve.
  - acidburnNSA 4y ago
    If you only look at LCOE and ignore backup, transmission, recycling at scale, etc then sure!
    - Retric 4y ago
      LCOE is vastly lower for battery backed solar, that’s why it’s so cheap. You also don’t need backup with batteries that’s the entire point. Individual nuclear power plants are single points of failure and go offline randomly. Nuclear needs redundancy to ensure a stable grid which further increases its costs. Transmission is again worse for nuclear because it’s so centralized. With solar you can locate it much closer to end users which cuts down on annual transmission losses.

edhelas 4y ago

Also it's mandatory to take care of the backup used when there is "no-wind/no-sun". You can have your electricity share coming from renewable that is increasing, if in the end you have 30-40 of gaz/coal as a backup to handle the time when renewable is not producing you'll no go way further. Example: Germany.

sveme 4y ago
Care to put some numbers on the no wind/no sun scenario? As an example, the share of renewables in Germany never dropped below 30% last year and that only happened a couple of days. Average renewable contribution was >50%.
- aeyes 4y ago
  I imagine that this is only for the grid production? If I charge my car with solar at home it won't move the meter, energy consumed by households with solar might not show up in the statistics. In reality renewable contribution might be even higher, unless there is correction for this.
- KptMarchewa 4y ago
  Wind in Poland right now works on 2% capacity factor. 152MW out of 7.72GW installed. There is solar now, so renewables are not so bad. However, at 5AM it was bad - wind was only on 5%, zero solar. https://i.imgur.com/LAJ2cKP.png https://i.imgur.com/LAJ2cKP.png
- barney54 4y ago
  What is your source for this? I’m highly skeptical because it means there was never a time of low wind at night ir when it was cloudy. February 26th of last year sure looks like a lot less than 30% renewable. https://mobile.twitter.com/energybants/status/1497392463731908614 https://mobile.twitter.com/energybants/status/14973924637319...
  - sveme 4y ago
    There's also hydro (incl. imported from Norway) and biomass. Source for total renewable over time is here: https://www.zeit.de/wirtschaft/energiemonitor-deutschland-gaspreis-spritpreis-energieversorgung https://www.zeit.de/wirtschaft/energiemonitor-deutschland-ga... There might be spells during the day where this is less than 30%, but that's what short term storage would be there for. The nightmare scenario, often mentioned, is weeks of clouds and low winds, which does not seem to have occurred last year, at least. And even when it's cloudy you still have some solar. By the way, I'm not arguing that all is well and everything is solved, I just hate this juvenile argument of "but what if it's cloudy and there is no wind for weeks", because that does not happen often, especially not on a continent-wide grid with lots of offshore wind power in one of the windiest seas in the world.