4 ms·

Sun doesn't shine for ~50% time everyday.

by dexwiz 10y ago

Naritai 10y ago
That would only be relevant if demand curves had a duty cycle of 50%. As OP mentions, in the warm parts of the world demand peaks during sunny times (thanks to AC), so there is good alignment.
manicdee 10y ago
Demand for electricity is not at peak for 90% of the day.
floatrock 10y ago
Solar and wind make up 2-3% of energy produced in the US. We can still make huge improvements just doubling a few times to bring it to 33% before talking about a 100% renewable grid. (Though some people have said that a 100% renewable grid is still achievable within reasonable economic conditions.)
CalChris 10y ago
Yes but peak demand is 9PM in the evening. Wind is down at that time as well. http://energyclub.stanford.edu/wp-content/uploads/2013/06/kavousian-2.png http://energyclub.stanford.edu/wp-content/uploads/2013/06/ka... Solar+wind don't have to provide 100% of the mix. They has to reduce the daytime fossil fuel generation.
- patrickk 10y ago
  Any idea why wind is up or down on a particular time? I would've thought it's extremely random.
  - CalChris 10y ago
    No, it's definitely not random. Off shore you get 24 hour constant wind, the synoptic wind. When we race to Hawaii, first you HAVE to get past the Farallones the first day and into the synoptic wind. If the inshore wind shuts down, you're bobbing all night with 0 wind. Get to the synoptic wind, set the spinnaker and it's a downhill sled race to Oahu. At the coast, you get marine layer driven winds in the afternoon, dying off in the evening. Stockton heats up midday, creates a low pressure and sucks in the marine layer. It cools off in the evening, shutting it down. Now, as to the wind chart, that's CA as a whole. Dunno. But wind is definitely not random by geography and season. Basically, it's solar driven.
- Johnny555 10y ago
  That doesn't line up with the CalISO graphs, for today, the peak is around 6pm - 7pm (still late in the day for Solar, but solar does ramp up in time to help with the daytime peak at around 8:30am): http://www.caiso.com/Pages/TodaysOutlook.aspx http://www.caiso.com/Pages/TodaysOutlook.aspx But if you look at the August 1st graph here, the summer peak is around 4pm: http://www.energyonline.com/Data/GenericData.aspx?DataId=18 http://www.energyonline.com/Data/GenericData.aspx?DataId=18 In any case, the peak solar output is around 4600MW while overall demand peaks at 29000MW, so solar still has a ways to go before we have to figure out what to do with all of the peak power.

Sun doesn't shine for ~50% time everyday.

by dexwiz 10y ago

Sun doesn't shine for ~50% time everyday.

That would only be relevant if demand curves had a duty cycle of 50%. As OP mentions, in the warm parts of the world demand peaks during sunny times (thanks to AC), so there is good alignment.

manicdee 10y ago

Demand for electricity is not at peak for 90% of the day.

floatrock 10y ago

Solar and wind make up 2-3% of energy produced in the US. We can still make huge improvements just doubling a few times to bring it to 33% before talking about a 100% renewable grid. (Though some people have said that a 100% renewable grid is still achievable within reasonable economic conditions.)

CalChris 10y ago

Yes but peak demand is 9PM in the evening. Wind is down at that time as well. http://energyclub.stanford.edu/wp-content/uploads/2013/06/kavousian-2.png http://energyclub.stanford.edu/wp-content/uploads/2013/06/ka... Solar+wind don't have to provide 100% of the mix. They has to reduce the daytime fossil fuel generation.

patrickk 10y ago
Any idea why wind is up or down on a particular time? I would've thought it's extremely random.
- CalChris 10y ago
  No, it's definitely not random. Off shore you get 24 hour constant wind, the synoptic wind. When we race to Hawaii, first you HAVE to get past the Farallones the first day and into the synoptic wind. If the inshore wind shuts down, you're bobbing all night with 0 wind. Get to the synoptic wind, set the spinnaker and it's a downhill sled race to Oahu. At the coast, you get marine layer driven winds in the afternoon, dying off in the evening. Stockton heats up midday, creates a low pressure and sucks in the marine layer. It cools off in the evening, shutting it down. Now, as to the wind chart, that's CA as a whole. Dunno. But wind is definitely not random by geography and season. Basically, it's solar driven.
Johnny555 10y ago
That doesn't line up with the CalISO graphs, for today, the peak is around 6pm - 7pm (still late in the day for Solar, but solar does ramp up in time to help with the daytime peak at around 8:30am): http://www.caiso.com/Pages/TodaysOutlook.aspx http://www.caiso.com/Pages/TodaysOutlook.aspx But if you look at the August 1st graph here, the summer peak is around 4pm: http://www.energyonline.com/Data/GenericData.aspx?DataId=18 http://www.energyonline.com/Data/GenericData.aspx?DataId=18 In any case, the peak solar output is around 4600MW while overall demand peaks at 29000MW, so solar still has a ways to go before we have to figure out what to do with all of the peak power.