4 ms·

Here are the graphs, as promised. https://i.imgur.com/bo0s7b0.png https://i.imgur.com/bo0s7b0.png Yes, these charts are horrific. I am showing daily energy g

Here are the graphs, as promised. https://i.imgur.com/bo0s7b0.png https://i.imgur.com/bo0s7b0.png Yes, these charts are horrific. I am showing daily energy generation for the last three months and the same period 12 months ago for comparison. I have also added day charts for January 14th through the 19th of this year (the period indicated by the red arrow) for readers to get a sense of what solar reality looks like. I've done this because it is too easy to say "On January 17th we generated 42.6 kWh" and fail to understand that between 12:20 and 13:15 the system dropped from 6.672 kW to 1.632 kW (power, not energy). Intelligent readers will be able to take these charts, play with some very basic numbers and understand the significant issues facing solar. If I wanted to have a system that delivered a reliable, usable 40 kWh of energy per day it would likely grow from the 13 kWh array I have today to somewhere between 50 kWh and 100kWh (if not more). And, on top of that, I would probably need somewhere in the order of 400 kWh of batteries for storage. In other words, an unrealizable monster. I know people are going to laugh at these numbers. These are the folks who never bother to fire-up a spreadsheet, run the numbers and reason. Take a look at the daily chart for January and tell me how much energy you would need to store to be able to have a real 40 kWh per day supply and how large the array would have to be. Then tell me how you are going to charge that pack in December, because it has to be fully charged so you can use it in January. That's the reality you need to understand. And the only way you will is to do the math. And, BTW, this is living in Southern California. Almost anywhere north of this latitude --places with far more weather-- the situation is even worse.

Schroedingersat 4y ago
So your system in perfect weather has a performance ratio of around 80% of what an average system optimized for total power would produce on average over the month, it has terrible low light performance (almost as if it's 2010 tech or you picked a bad inverter for your use case or it's badly installed), you're pretending transmission and wind don't exist and that any suggestion of a mix involving solar be exclusively off grid, and that dispatchable backup like biomethane and hydro for a few hundred hours a year is both impossible and is never going to be involved in any nuclear based system? You're also trying to pretend weather is a 1:1 correlation with latitude and that wind and solar aren't anti-correlated. You know a vertical south facing bifacial panel a bit north of Calgary will produce just as much power in december as a flat one in singapore right? California already has about 7% hydro and biomass capacity. Include 7% dispatchable generation, then adjust your stats to match or look up the output of a real modern fixed tilt utility (or well designed off grid) system with a decent MPPT, adequate low light performance and bypass diodes, and you'll be able to see you've actually provided fairly strong evidence that 12hr storage, 7% dispatch and 100% overprovision (which you can use with your 3 day dispatchable load called an EV to avoid curtailment if you drive an average amount) on a 93% solar system is more than sufficient. Include transmission to the other side of a range to get less correlated weather and the storage and overprovision drop significantly. Add onshore wind and the requirement for dispatch, overprovision and storage plummets. Add offshore wind and HVDC and 3 hours with 30% curtailment into an electrolyser for fertilizer is overkill.
- robomartin 4y ago
  > So your system in perfect weather has a performance ratio of around 80% of what an average system optimized for total power would produce on average over the month Sorry buddy, the level of ignorance you continue to exhibit about real-life solar is astounding. The fact that you say tuff like this continues to show you are what I call a “google search expert”. Go build something. Learn. Maybe then you’ll understand. You also have to learn to listen to people who know more than you think you know. Perfect solar only exists in fantasy land. In the real world things are different. Nobody has a system on their roof that Mets your fantasy specifications. Nobody. You mentioned Singapore. One of our customers has a 300 kW solar array there. Care to guess how much power they actually generate. Hint: Rain. Lots of rain.
  - Schroedingersat 4y ago
    > Sorry buddy, the level of ignorance you continue to exhibit about real-life solar is astounding. The fact that you say tuff like this continues to show you are what I call a “google search expert”. Go build something. Learn. Maybe then you’ll understand. Good thing the industry has specific metrics and models for all of these things and there is plenty of data published for integration studies. GTI on a fictional perfect bifacial system on a good day at that latitude in January would be 70-80kWh not 50. A real utility system in easy transmission range of LA including an 85-90% performance ratio is about 50kWh/day in January. You can see clearly from the posted graphs that the system has poor low light performance, less than ideal tilt and that's where the missing energy is. A utility site or well sited standalone off grid system (or one wherebthe building was designed with solar in mind) would not have this. 3.8kWh/day/kWp in January in california isn't some magical ideal. It's completely normal. > You mentioned Singapore. One of our customers has a 300 kW solar array there. Care to guess how much power they actually generate. Hint: Rain. Lots of rain. You completely missed the point here and made it for me. Weather is not latitude. The idea that solar is useless anywhere outside the tropics or that a summer optimised system's winter performance is representative of a winter-optimized system is a myth made up by insane conservatives. Local weather has a larger effect than 50 degrees of latitude during winter. Tilt is also very important -- you do not want to install an off grid system (or a system in a saturated market) at the angle which maximises annual output, you install it at the angle which maximises winter output. Once Europe saturates summer PV, adding more doesn't become useless, you just slap some on a south facing wall or use it as a fence in a paddock. Read. Pay some minimal amount of attention to what you're responding to and to new developments. You also have to learn to listen to people who know more than you think you know.

Schroedingersat 4y ago

So your system in perfect weather has a performance ratio of around 80% of what an average system optimized for total power would produce on average over the month, it has terrible low light performance (almost as if it's 2010 tech or you picked a bad inverter for your use case or it's badly installed), you're pretending transmission and wind don't exist and that any suggestion of a mix involving solar be exclusively off grid, and that dispatchable backup like biomethane and hydro for a few hundred hours a year is both impossible and is never going to be involved in any nuclear based system? You're also trying to pretend weather is a 1:1 correlation with latitude and that wind and solar aren't anti-correlated. You know a vertical south facing bifacial panel a bit north of Calgary will produce just as much power in december as a flat one in singapore right? California already has about 7% hydro and biomass capacity. Include 7% dispatchable generation, then adjust your stats to match or look up the output of a real modern fixed tilt utility (or well designed off grid) system with a decent MPPT, adequate low light performance and bypass diodes, and you'll be able to see you've actually provided fairly strong evidence that 12hr storage, 7% dispatch and 100% overprovision (which you can use with your 3 day dispatchable load called an EV to avoid curtailment if you drive an average amount) on a 93% solar system is more than sufficient. Include transmission to the other side of a range to get less correlated weather and the storage and overprovision drop significantly. Add onshore wind and the requirement for dispatch, overprovision and storage plummets. Add offshore wind and HVDC and 3 hours with 30% curtailment into an electrolyser for fertilizer is overkill.

robomartin 4y ago
> So your system in perfect weather has a performance ratio of around 80% of what an average system optimized for total power would produce on average over the month Sorry buddy, the level of ignorance you continue to exhibit about real-life solar is astounding. The fact that you say tuff like this continues to show you are what I call a “google search expert”. Go build something. Learn. Maybe then you’ll understand. You also have to learn to listen to people who know more than you think you know. Perfect solar only exists in fantasy land. In the real world things are different. Nobody has a system on their roof that Mets your fantasy specifications. Nobody. You mentioned Singapore. One of our customers has a 300 kW solar array there. Care to guess how much power they actually generate. Hint: Rain. Lots of rain.
- Schroedingersat 4y ago
  > Sorry buddy, the level of ignorance you continue to exhibit about real-life solar is astounding. The fact that you say tuff like this continues to show you are what I call a “google search expert”. Go build something. Learn. Maybe then you’ll understand. Good thing the industry has specific metrics and models for all of these things and there is plenty of data published for integration studies. GTI on a fictional perfect bifacial system on a good day at that latitude in January would be 70-80kWh not 50. A real utility system in easy transmission range of LA including an 85-90% performance ratio is about 50kWh/day in January. You can see clearly from the posted graphs that the system has poor low light performance, less than ideal tilt and that's where the missing energy is. A utility site or well sited standalone off grid system (or one wherebthe building was designed with solar in mind) would not have this. 3.8kWh/day/kWp in January in california isn't some magical ideal. It's completely normal. > You mentioned Singapore. One of our customers has a 300 kW solar array there. Care to guess how much power they actually generate. Hint: Rain. Lots of rain. You completely missed the point here and made it for me. Weather is not latitude. The idea that solar is useless anywhere outside the tropics or that a summer optimised system's winter performance is representative of a winter-optimized system is a myth made up by insane conservatives. Local weather has a larger effect than 50 degrees of latitude during winter. Tilt is also very important -- you do not want to install an off grid system (or a system in a saturated market) at the angle which maximises annual output, you install it at the angle which maximises winter output. Once Europe saturates summer PV, adding more doesn't become useless, you just slap some on a south facing wall or use it as a fence in a paddock. Read. Pay some minimal amount of attention to what you're responding to and to new developments. You also have to learn to listen to people who know more than you think you know.