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  • estimating yearly production

    just received my level 1 application back from the local electrical company, with requests to correct some info. MY yearly estimated production (based on shading estimates and pvwatts) was more than my annual electric consumption, which is apparently a no-no. They want the estimated production to be lower. Should I just pick some arbitrary number to make it work, or raise the shading losses until the numbers work?
    Also, they stated that my single line diagram is missing the DC system info. I'll add the diagram, if anyone has some criticism I'd appreciate it. FWIW, I'm doing this project scrounging old stock items, trying to keep it as low cost as possible.
    SD

  • #2
    here
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    • #3
      Originally posted by badwithusernames View Post
      just received my level 1 application back from the local electrical company, with requests to correct some info. MY yearly estimated production (based on shading estimates and pvwatts) was more than my annual electric consumption, which is apparently a no-no. They want the estimated production to be lower. Should I just pick some arbitrary number to make it work, or raise the shading losses until the numbers work?
      Also, they stated that my single line diagram is missing the DC system info. I'll add the diagram, if anyone has some criticism I'd appreciate it. FWIW, I'm doing this project scrounging old stock items, trying to keep it as low cost as possible.
      SD
      On the production estimate issue, if you're unsure of what they are asking, why not just call and ask them what they want or mean, or if there is a limit to system size for the purpose of limiting systme production ?

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      • #4
        The simple solution is to tell them you are going to buy an EV. There is a guy on this forum who is very reasonable and he has been contemplating buying an EV as long as I have been on this forum.

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        • #5
          It is bad practice to fudge numbers. It is even worse practice to say that you're thinking of fudging numbers on a public forum. We have been (pleasantly) surprised to find that some important people read this forum.

          The idea of mentioning that your electric usage is planning to go up is a good solution, if true.

          If you have any trees that shade the panels, they will certainly grow and increase shading with time. My rule of thumb is that average trees grow 1.5 feet per year, but it varies with climate and tree species.

          I've read that used equipment is not eligible for the federal solar tax credit. The government does this to avoid double dipping, because they may have given a tax credit on the equipment when it was new. The tree-hugger in me loves the idea of recycling old equipment, but some times, it doesn't make financial sense.
          7kW Roof PV, APsystems QS1 micros, Nissan Leaf EV

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          • #6
            There is a big difference between fudging numbers and the prospect of buying an EV. I don't know why he keeps saying he is going to buy an EV.
            Maybe paralysis by analysis.
            Last edited by Ampster; 08-08-2020, 12:21 PM.

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            • #7
              If your POCO wants you to limit you solar output to just cover your past yearly use, you can always build a smaller system to fit into their requirements.

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              • #8
                Originally posted by bob-n View Post
                It is bad practice to fudge numbers. It is even worse practice to say that you're thinking of fudging numbers on a public forum. We have been (pleasantly) surprised to find that some important people read this forum.

                The idea of mentioning that your electric usage is planning to go up is a good solution, if true.

                If you have any trees that shade the panels, they will certainly grow and increase shading with time. My rule of thumb is that average trees grow 1.5 feet per year, but it varies with climate and tree species.

                I've read that used equipment is not eligible for the federal solar tax credit. The government does this to avoid double dipping, because they may have given a tax credit on the equipment when it was new. The tree-hugger in me loves the idea of recycling old equipment, but some times, it doesn't make financial sense.
                IMO, and on the chance the OP is unaware of it, good mention about no tax credit for used equipment. Seems like we all missed that in the original post.

                If I was the OP, and since they are the horse's mouth in this case, I'd still call the POCO and ask for clarification of PV size/output limits before I made a decision on how to deal with any such limits, particularly how they maybe impacted by future plans.

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                • #9
                  Originally posted by Ampster View Post
                  The simple solution is to tell them you are going to buy an EV. There is a guy on this forum who is very reasonable and he has been contemplating buying an EV as long as I have been on this forum.
                  I'm actually contemplating a spa, which would certainly set the numbers where the utility company would be happy. Thank you all for the input..
                  I'm not an advocate of fudging anything when it comes to electrical.. that said many of the points raised are hold true. My electrical consumption will probably increase, as will shading.... so at some point the system will not produce as much as I am using. I will call and make some more specific inquiries. The first call didn't get me anywhere, as the woman answering the phone was clearly not happy to answer questions.
                  About the tax credit. I have weighed several ways of doing this, and with some careful digging I did find deals that were good enough that I was saving even more than the tax credit would have netted me. And, at this point in time, with the way 2020 has gone, we may actually end up with a loss this year so a tax credit wouldn't really be any good. I'm under 4.5k for everything so far, and installing it myself; to have gone with a comparable system new would have been around 10k. As it is I have bought the inverters new, but deeply discounted, so there is something to claim if I wanted.
                  Still curious was to what they want to see for the DC system. The panels are shown on the drawing, maybe they want the rapid shutdown added? I will have to ask
                  SD

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                  • #10
                    Originally posted by badwithusernames View Post
                    ...........
                    Still curious was to what they want to see for the DC system. The panels are shown on the drawing, maybe they want the rapid shutdown added? I will have to ask
                    SD
                    Usually the Power Company is only concerned with the capacity and that anything that interconnects, like the inverter, meets UL standards. The wiring details behind the meter are usually the concern of the building department issuing the building permit, which is a prerequisite to getting the Power Company approval. Rapid Shut down is a recent requirement in NEC and it may be required by your building department. The only exception to the foregoing is in the case of a municipal utility which is part of the city issuing the permits. In that case the Power Company (municipal utility) may have been delegated that task.

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                    • #11
                      Well, the second call to PSEG here in south Jersey went much better than the first and I was given some clarification:
                      Regarding the DC system, they want the array total wattage listed in multiple places. I had it listed on the single line diagram, and filled out in the application, but they wanted it listed everywhere.
                      And about the production VS consumption. Apparently here PSEG doesn't want you to make more than you use, though that tidbit of info isn't listed anywhere. So; I explained that we have recently added 6 tons of central air and are adding a spa this fall, and basing my usage on last years bills wasn't accurate.Was told that I need to do an updated load calculation for our place with all of the new equipment. That in conjunction with my recent bills (show increased usage compared to last year) should be enough to push the system through.
                      I will likely increase the loss due to shading in my calculations, as when you pull up the property on google maps, you can see the trees are numerous.

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                      • #12
                        Originally posted by Ampster View Post
                        Usually the Power Company is only concerned with the capacity and that anything that interconnects, like the inverter, meets UL standards. The wiring details behind the meter are usually the concern of the building department issuing the building permit, which is a prerequisite to getting the Power Company approval. Rapid Shut down is a recent requirement in NEC and it may be required by your building department. The only exception to the foregoing is in the case of a municipal utility which is part of the city issuing the permits. In that case the Power Company (municipal utility) may have been delegated that task.
                        That used to be true. More and more utilities are now requesting panel brand, model, number, tilt, azimuth & shading. They are using this data to model system output over time for grid stability modeling

                        Andy

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                        • #13
                          Originally posted by PVAndy View Post

                          That used to be true. More and more utilities are now requesting panel brand, model, number, tilt, azimuth & shading. They are using this data to model system output over time for grid stability modeling
                          Yes, I can understand the reason to do that to estimate or verify capacity..Are they going as far as reviewing NEC compliance like Rapid Shut Down or buss bar capacity on sub panels? So far in California they have not.
                          Last edited by Ampster; 08-13-2020, 10:22 AM.

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                          • #14
                            update, and another question: I did recalculate my yearly electric usage to include this past June and July, which show my new AC system's usage. And then I read a bit more on shading, recalculated my production estimate using (maybe more accurate) shading numbers and exact panel angles. After all of that my consumption and production numbers are very close. I still completed the PSEG load analysis worksheet, which shows my consumption could be much, much higher, so hopefully this works.
                            On the form there is a section that I'm not sure how to answer, maybe someone can advise me?
                            Current consumption: 8212kwh
                            Estimated gross production: 8200kwh
                            Do you plan to export power Y/N
                            If yes, estimated maximum?
                            So, if they don't want production to exceed consumption, how would I export power? I know this is a question for the power company, but I forgot to call today and this will bug me all weekend. It's literally the last hurdle so I can resubmit the application. In other news, my plans and permit were approved by the township! Progress!
                            Thanks in advance. SD

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                            • #15
                              To answer your question, you might produce more during the day but consume it during the night. Also seasonal differences could cause you to export during a sunny month and consume during a cloudy month. I don't think it is a trick question.

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