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Solar city broken promise

Discussion in 'Model 3: Battery & Charging' started by bomquito, Sep 1, 2018.

  1. bomquito

    bomquito Member

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    I’ve been charging my model 3 at home off peak and noticed that the energy produced from solar is not sufficient enough to sustain. Let me share my story.

    9.1 kW system installed in August last year with a promised minimum generation of 13000 kWh. I add all the monthly generation numbers from the solar city app and come up with ~14300 kWh. When I check the electricity bill, my one year consumption from 08-17 to 08-18 is ~8800 and net surplus generation is -700 kWh, which translates to a total of ~9500 kWh recorded . My question is: where did the ~4800 kWh difference go? Am I losing them in transit coming from the solar panels back to the grid?
     
  2. SDRick

    SDRick Member

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    If I understand correctly, the answer is pretty simple.
    Your electricity provider is not measuring your consumption while your panels are producing. As far as your utility is concerned the meter only measures net power going into or out of the grid.
     
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  3. bomquito

    bomquito Member

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    So should I be calling Tesla energy or SoCal Edison for the difference issue?
     
  4. mspohr

    mspohr Well-Known Member

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    Why on earth would you jump to the conclusion that it's a "Solar City Broken Promise" when you can see that your system is generating more than they "promised" ? Are you always this confrontational ? Are you always this clueless about math ?
    If you weren't able to figure out this simple math problem on your own, you could have just asked here politely for some help. Instead, you go on a rant.
    Simple answer that others have pointed out is that the power company only measures the excess that you deliver to the grid and what you draw from the grid. The power company has no way to measure your self consumption. The Solar City app measures total generation.
     
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  5. SDRick

    SDRick Member

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    Calling will not do any good. Consider yourself lucky! There are utilities that do actually measure your personal consumption and charge you for it even though the system is a net generator!
     
  6. bomquito

    bomquito Member

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    I was just trying to generate a response. I am sorry for sounding confrontational. I simply just need help determining the difference between that my panels generate vs. recording data from SCE
     
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  7. ucmndd

    ucmndd Active Member

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    Your electric meter can only sense energy traveling through it. That's it. As in, how much energy you consume from the grid and/or how much energy you send back.

    During the day, your solar panels are producing electricity while your home is consuming electricity. That energy is going directly from your panels to your appliances. It never traverses the meter.

    You can see for yourself, quite clearly, that the net generation of your panels over the year exceeds the "promise" that Solar City gave you.
     
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  8. Ejl80

    Ejl80 Supporting Member

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    So, no where did solar city break any promises to you, unless they promised to teach you math?
     
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  9. invalid

    invalid Member

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    Others are correct. I also have a system from Solar City and pretty sure the agent had discussed "understanding your utility bill" with us. For us, its PG&E.
     
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  10. Rocky_H

    Rocky_H Active Member

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    I'm not with Solar City, but I have to keep my own spreadsheet to do the math and subtract to get the consumption numbers because of this issue with net metering reporting. I get the monthly report from Enphase, showing our total generation. Then I log into our energy company to get the monthly net amount. Generated energy minus our consumed energy = the net plus or minus total. But I only have the first and last numbers, so it's just a subtracting formula to calculate that consumption number for each month.

    Utter horse manure. You were flying off the handle, jumping to conclusions with a finger-pointing accusation of wrongdoing, not just asking for a response. Trying to generate a response would look something like: "These numbers look weird. What is going on?"
     
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  11. YauKwan

    YauKwan Member

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    This video might help you understand solar, net metering and adjust your charging habits.

     
  12. SSonnentag

    SSonnentag Supporting Member

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    Your power company meter only records what is sent to the grid and what comes off the grid. It cannot see the power your house is consuming when the panels are producing power and sending it directly to your house. The meter will only show excess power generated or power consumed in excess of what your panels are producing.
     
  13. mspohr

    mspohr Well-Known Member

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    Here's an example from my home system showing generation, use, export and import.
    upload_2018-9-11_9-25-32.png

    I have sensors which measure production (green) and consumption (red). The lines are immediate values and the shaded areas are cumulative for the day.
    You can see the production (green line) goes up during the day to a cumulative of about 55 kWh. Consumption spikes with use. The 4 kW spikes are my hot tub heater, 2 kW spikes are my heat pump. The 7 kW spike in the middle is my car charging.
    When the green line is above the red line, the difference is fed into the grid. When the green line is below the red line, I am drawing power from the grid.

    Here is a graph of monthly net:
    upload_2018-9-11_9-33-52.png
    You can see from this the simple math that shows
    upload_2018-9-11_9-36-32.png
    The power company only sees what you export (yellow) and what you import (red). They don't know about generation or self consumption.
     
  14. davewill

    davewill Member

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    Actually, I think it's worse to post a rant just to "generate a response" than to just admit a mistaken angry post.
     

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