3 ms·

Peak power usage is around 7-8PM, this discrepancy is the source of the duck curve. More storage could allow tons more solar to be installed. https://cleantech

Peak power usage is around 7-8PM, this discrepancy is the source of the duck curve. More storage could allow tons more solar to be installed. https://cleantechnica.com/2014/07/21/utilities-cry-fowl-over-duck-chart-and-distributed-solar-powercrying-fowl-or-crying-wolf-open-season-on-the-utilitys-solar-duck-chart/ https://cleantechnica.com/2014/07/21/utilities-cry-fowl-over... (deepsun - the "no sun" critical event happens every night)

_delirium 9y ago
7-8pm according to that link is the net peak, after solar production has canceled out the original afternoon peak. The problem is that even though solar supply does roughly coincide with the peak of demand, solar production has increased enough that, since about 2013, it's gone past the point of offsetting peak afternoon A/C usage, to now producing an actual net trough in the afternoon hours (you can see the afternoon extremum flips from a local maximum to a local minimum from 2012 to 2014, and just keeps going further down every year since, as peak afternoon solar grows faster than peak afternoon A/C). The new net peak around 7-8pm is because demand has a long tail into the early evening, while solar drops off sharply around 5-7pm. But yeah the end result is that it does cause a problem for grid management if you add more incremental solar, since the original afternoon peak it helped smooth out has long since been smoothed and then some.
- akira2501 9y ago
  In California, the peak is actually at 6pm. At that time, Solar is generally producing 6.6 GW from around 9.6 GW at noon. http://www.caiso.com/Pages/TodaysOutlook.aspx http://www.caiso.com/Pages/TodaysOutlook.aspx
- Animats 9y ago
  Wind is really variable, and often way out of sync with load. I just looked at PJM's dashboard, and peak wind in the last 24 hours was 4 gigawatts at 4 AM. Wind bottomed out at 0.65 GW at 8 PM. That's total output from wind farms from Illinois to New England. Averaging over a large area isn't that helpful. Piping energy in from the wind corridor that runs up from the Texas panhandle to Canada has promise. The wind is steadier there. It's quite possible to run megavolt DC power lines now; China has 16,000Km of them. California has had a half-megavolt DC link from Oregon to Southern California since the 1970s.
tedsanders 9y ago
To be clear, 7-8PM is the daily peak. The annual peak is around 2-5PM. The annual peak is far more relevant for grid capacity planning. So there's still plenty of room for solar in California. https://www.caiso.com/Documents/CaliforniaISOPeakLoadHistory.pdf https://www.caiso.com/Documents/CaliforniaISOPeakLoadHistory... (I used to work for a CA utility.)
deepsun 9y ago
Calculations show that it's less expensive to maintain more solar panels than maintaining storage. (And, instead of solar panels -- wind turbines, as they are mostly better than solar panels). Storage is better to be left for critical events (no sun + no wind + peak consumption). And even then it's better to keep several gas power plants to cover those events.
- epistasis 9y ago
  I'd love to see those studies, that's unfamiliar to me! With the quickly dropping costs of storage, I wonder where/if there's and inflection point.
  - KekDemaga 9y ago
    Its hard to imagine a more efficient solar energy storage medium than oil and gas. I'd be curious how close it is myself.
    - jessaustin 9y ago
      I'm not sure how efficient hydrocarbons are as storage media; the point is that eras of geological processes have already done the work of storing energy in that form.
    - epistasis 9y ago
      I was more interested in the claim of having more solar negating the need for storage. Oil and gas are horrifyingly inefficient storage mechanisms. Round trip will be less than 50%, best case. That said, power to gas may be worthwhile if there's a ton of excess electrical power certain times of the year and the capital costs of power to gas is low enough.
      - KekDemaga 9y ago
        I'm thinking more in terms of availability, cost, volume and portability. I might be wrong but wouldn't a oil tanker full of diesel fuel contain a great deal more potential energy than the same volume of the best battery cell we can produce for this purpose?

_delirium 9y ago

7-8pm according to that link is the net peak, after solar production has canceled out the original afternoon peak. The problem is that even though solar supply does roughly coincide with the peak of demand, solar production has increased enough that, since about 2013, it's gone past the point of offsetting peak afternoon A/C usage, to now producing an actual net trough in the afternoon hours (you can see the afternoon extremum flips from a local maximum to a local minimum from 2012 to 2014, and just keeps going further down every year since, as peak afternoon solar grows faster than peak afternoon A/C). The new net peak around 7-8pm is because demand has a long tail into the early evening, while solar drops off sharply around 5-7pm. But yeah the end result is that it does cause a problem for grid management if you add more incremental solar, since the original afternoon peak it helped smooth out has long since been smoothed and then some.

akira2501 9y ago
In California, the peak is actually at 6pm. At that time, Solar is generally producing 6.6 GW from around 9.6 GW at noon. http://www.caiso.com/Pages/TodaysOutlook.aspx http://www.caiso.com/Pages/TodaysOutlook.aspx
Animats 9y ago
Wind is really variable, and often way out of sync with load. I just looked at PJM's dashboard, and peak wind in the last 24 hours was 4 gigawatts at 4 AM. Wind bottomed out at 0.65 GW at 8 PM. That's total output from wind farms from Illinois to New England. Averaging over a large area isn't that helpful. Piping energy in from the wind corridor that runs up from the Texas panhandle to Canada has promise. The wind is steadier there. It's quite possible to run megavolt DC power lines now; China has 16,000Km of them. California has had a half-megavolt DC link from Oregon to Southern California since the 1970s.

tedsanders 9y ago

To be clear, 7-8PM is the daily peak. The annual peak is around 2-5PM. The annual peak is far more relevant for grid capacity planning. So there's still plenty of room for solar in California. https://www.caiso.com/Documents/CaliforniaISOPeakLoadHistory.pdf https://www.caiso.com/Documents/CaliforniaISOPeakLoadHistory... (I used to work for a CA utility.)

deepsun 9y ago

Calculations show that it's less expensive to maintain more solar panels than maintaining storage. (And, instead of solar panels -- wind turbines, as they are mostly better than solar panels). Storage is better to be left for critical events (no sun + no wind + peak consumption). And even then it's better to keep several gas power plants to cover those events.

epistasis 9y ago
I'd love to see those studies, that's unfamiliar to me! With the quickly dropping costs of storage, I wonder where/if there's and inflection point.
- KekDemaga 9y ago
  Its hard to imagine a more efficient solar energy storage medium than oil and gas. I'd be curious how close it is myself.
  - jessaustin 9y ago
    I'm not sure how efficient hydrocarbons are as storage media; the point is that eras of geological processes have already done the work of storing energy in that form.
  - epistasis 9y ago
    I was more interested in the claim of having more solar negating the need for storage. Oil and gas are horrifyingly inefficient storage mechanisms. Round trip will be less than 50%, best case. That said, power to gas may be worthwhile if there's a ton of excess electrical power certain times of the year and the capital costs of power to gas is low enough.
    - KekDemaga 9y ago
      I'm thinking more in terms of availability, cost, volume and portability. I might be wrong but wouldn't a oil tanker full of diesel fuel contain a great deal more potential energy than the same volume of the best battery cell we can produce for this purpose?