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  • gvl
    Solar Fanatic
    • Mar 2015
    • 288

    6kW system in Agoura Hills

    New user here. Looks like I'm ready to finally pull the trigger on solar this year. SCE territory, South-East facing roof at 130-degree azimuth, lots of room, no shading. My installer whom I generally trust is initially quoting me $3.95/watt DC on a 20-panel turn-key system using LG300N1C panels and Enphase M250 inverters. Is this a more or less reasonable price for a straightforward install on a roof with asphalt shingles? Should I look into using a string inverter and lower-efficiency panels to reduce up-front costs? I have an EV and not excluding a possibility of adding a second one, so being able to increase the size of the array in the future is somewhat a concern.
  • thejq
    Solar Fanatic
    • Jul 2014
    • 599

    #2
    Any way you can put it on a south, south west or even a west facing roof? That south east roof will "kill" your production, especially considering you have an EV and probably on some EV-TOU plan that pays the most in the afternoon. Not sure about pricing in Agoura Hills but sounds a little higher than San Diego.
    16xLG300N1C+SE6000[url]http://tiny.cc/ojmxyx[/url]

    Comment

    • gvl
      Solar Fanatic
      • Mar 2015
      • 288

      #3
      I have some small SW facing roof over the garage, probably good for 10 panels at most with some shading late in the day. I realize that the SE facing roof is not ideal, especially with the recent TOU on-peak window changes from SCE. However PVWatts tells me that even if I could fit all 6kW on that SW section my annual production would only grow by 327kWh, so in an ideal case scenario when all that extra energy is produced at the highest on-peak rate of 46c/kWh with no consumption it would save me 150 bucks a year, in reality I can only put a limited number of panels there which will also complicate the installation and likely increase the up-front cost I don't feel like it is really worth it not to mention this is a street-facing slope so while I personally couldn't care less about the aesthetics the looks of the street-facing panels may turn off some buyers should I decide to sell my home.

      Comment

      • thejq
        Solar Fanatic
        • Jul 2014
        • 599

        #4
        Originally posted by gvl
        I have some small SW facing roof over the garage, probably good for 10 panels at most with some shading late in the day. I realize that the SE facing roof is not ideal, especially with the recent TOU on-peak window changes from SCE. However PVWatts tells me that even if I could fit all 6kW on that SW section my annual production would only grow by 327kWh, so in an ideal case scenario when all that extra energy is produced at the highest on-peak rate of 46c/kWh with no consumption it would save me 150 bucks a year, in reality I can only put a limited number of panels there which will also complicate the installation and likely increase the up-front cost I don't feel like it is really worth it not to mention this is a street-facing slope so while I personally couldn't care less about the aesthetics the looks of the street-facing panels may turn off some buyers should I decide to sell my home.
        While I can't comment on what it will do to your property value, but your calculation is a little off. When you change the orientation not only you get more production, but your entire bell curve will move from peaking in the morning to afternoon. Just for example you 6K system's annual production is 14000 KWh of which 9000 is produced in the summer (highest TOU pay out). For east facing, let's say 1/5 of the production is after 2PM and for SW it's 1/2 (my SW peaks around 1:45-2:15 PM in the summer). So for the summer, the difference is roughly 9000*1/2*(.46+.30) - 9000*(1/5*.46+4/5*.3) = $432 on top of the $150 you already calculated. But of course, it didn't account for usage during the day. So just scale down the previous number by the % of usage. It's just a rough estimate, you need to go through it again with your bell curves.
        16xLG300N1C+SE6000[url]http://tiny.cc/ojmxyx[/url]

        Comment

        • gvl
          Solar Fanatic
          • Mar 2015
          • 288

          #5
          Ok, you're right my estimate was too naive, however scaling down the numbers in your example to the estimated 9500 kWh of total annual production from a 6kW array per PVWatts for the SW facing roof installation and further by 1/2 because I can only fit 3kW there we arrive at roughly $300 a year difference with no usage that includes my original $150, which is about what I will be spending on trimming of my neighbor trees to reduce shading on the SW segment if I'm lucky he agrees to it. Still not worth doing it in my book.

          Comment

          • thejq
            Solar Fanatic
            • Jul 2014
            • 599

            #6
            Originally posted by gvl
            Ok, you're right my estimate was too naive, however scaling down the numbers in your example to the estimated 9500 kWh of total annual production from a 6kW array per PVWatts for the SW facing roof installation and further by 1/2 because I can only fit 3kW there we arrive at roughly $300 a year difference with no usage that includes my original $150, which is about what I will be spending on trimming of my neighbor trees to reduce shading on the SW segment if I'm lucky he agrees to it. Still not worth doing it in my book.
            Why just 9500 KWh? Maybe pvwatt is a little pessimistic. I'm hoping to get 10K KWh/year with my 4.8K system. If you have no shades, try "premium" and "0%" loss.
            16xLG300N1C+SE6000[url]http://tiny.cc/ojmxyx[/url]

            Comment

            • gvl
              Solar Fanatic
              • Mar 2015
              • 288

              #7
              Originally posted by thejq
              Why just 9500 KWh? Maybe pvwatt is a little pessimistic. I'm hoping to get 10K KWh/year with my 4.8K system. If you have no shades, try "premium" and "0%" loss.
              0% loss? Sounds a bit optimistic for the imperfect world we live in I scaled the losses down to 6% and selected premium, which brought me up to 10500 kWh, unfortunately it doesn't change the fact I have limited SW roof area that is affected by shading.

              Comment

              • sensij
                Solar Fanatic
                • Sep 2014
                • 5074

                #8
                9500 kWh from a 6 kW array is a much better estimate than 14000 kWH, or 10000 kWh from a 4.8 kW array. Panel orientation will have an impact with respect to value in a TOU plan, but the SCE TOU-D-A plan still pays generously for production off-peak (8am - 2pm, and 8 pm-10pm, which doesn't matter), so even the SE panels will probably generate more value in TOU for EV drivers than they will in the straight tier plan.

                Does that price include a main service panel upgrade? If so, it is slightly on the high side, but still pretty good. If it does not, you might want to shop it around a bit more.
                CS6P-260P/SE3000 - http://tiny.cc/ed5ozx

                Comment

                • gvl
                  Solar Fanatic
                  • Mar 2015
                  • 288

                  #9
                  Originally posted by sensij

                  Does that price include a main service panel upgrade? If so, it is slightly on the high side, but still pretty good. If it does not, you might want to shop it around a bit more.
                  No, due to reasons that deserve a separate topic the panel had to be taken care of previously. Just need to install the panels and drop solar feed on the panel, that's it. You think it is too high for the equipment spec'd or in just general I can spend less for an equivalent system with less expensive components?

                  Comment

                  • thejq
                    Solar Fanatic
                    • Jul 2014
                    • 599

                    #10
                    PVWatt says I should get 8710 KWh with "premium" and "0%" loss. But my total so far is about 10% higher than that. So maybe I'm a little optimistic and weather has been nice, but 9500 KWh is probably doable ... I'm hoping But we digress ...
                    16xLG300N1C+SE6000[url]http://tiny.cc/ojmxyx[/url]

                    Comment

                    • sensij
                      Solar Fanatic
                      • Sep 2014
                      • 5074

                      #11
                      Originally posted by gvl
                      No, due to reasons that deserve a separate topic the panel had to be taken care of previously. Just need to install the panels drop solar feed on the panel, that's it. You think it is too high for the equipment spec'd or in just general I can spend less for an equivalent system with less expensive components?
                      I think you could get an equivalent system for a bit less with some shopping...

                      In December, user JD31 shared in this post some quotes.

                      LG280's were about 0.25 / W more than Hanwha panels, and LG280's should be probably at least 0.10 / W less than 300's. I think paying $3.50 - $3.75 / W is reasonable for the 300's if your SE roof doesn't have space for something less efficient, depending on the installer.
                      CS6P-260P/SE3000 - http://tiny.cc/ed5ozx

                      Comment

                      • gvl
                        Solar Fanatic
                        • Mar 2015
                        • 288

                        #12
                        Originally posted by sensij
                        I think you could get an equivalent system for a bit less with some shopping...

                        In December, user JD31 shared in this post some quotes.

                        LG280's were about 0.25 / W more than Hanwha panels, and LG280's should be probably at least 0.10 / W less than 300's. I think paying $3.50 - $3.75 / W is reasonable for the 300's if your SE roof doesn't have space for something less efficient, depending on the installer.
                        $3.50 - $3.75/W with Enphase M250s? They are about $1500 more for a 6kW system than the Solar Edge 7600 that jd31 was quoted for. I should have no problem finding room for less efficient panels as the roof is huge, I should probably do that. Sounds like my guy is more or less in the ballpark, I suppose paying $0.20 extra per W on a 6kW system to someone I can trust is not too bad of a concept?

                        Comment

                        • J.P.M.
                          Solar Fanatic
                          • Aug 2013
                          • 14924

                          #13
                          Try this: lots of room, no shade --->> LG280 etc. w/ string inverter(s). Face as many south as possible. In San Diego etc. $3.50/$3.5/Watt for that combo ought to be doable and different enough to save your guy some face when he swallows on price, provided you think he's worth it and feel comfortable with him as your vendor. Low buck for its own sake is false economy. Fair and tough negotiating is good business. If he wants your business help him with an opportunity to lower his price by slight changes that result in a better system and savings for all.

                          On the other hand, get any other quotes ? It's just business.

                          9,500-10,500 kWh/yr. ought to be doable. Much more might be a stretch.

                          I'd not recommend using PVWatts the way Thejq suggests.

                          Comment

                          • gvl
                            Solar Fanatic
                            • Mar 2015
                            • 288

                            #14
                            Originally posted by J.P.M.
                            Try this: lots of room, no shade --->> LG280 etc. w/ string inverter(s). Face as many south as possible. In San Diego etc. $3.50/$3.5/Watt for that combo ought to be doable and different enough to save your guy some face when he swallows on price, provided you think he's worth it and feel comfortable with him as your vendor. Low buck for its own sake is false economy. Fair and tough negotiating is good business. If he wants your business help him with an opportunity to lower his price by slight changes that result in a better system and savings for all.

                            On the other hand, get any other quotes ? It's just business.

                            9,500-10,500 kWh/yr. ought to be doable. Much more might be a stretch.

                            I'd not recommend using PVWatts the way Thejq suggests.
                            My guy is super-flexible and will put whatever components I want in the system if he can get them, for me it is just a matter of figuring out the most optimal solution using current technology and the specifics of my site in terms of $$$ that also gives me room for future expansion while making sure he is not overcharging me. I'm working on getting additional quotes.

                            Comment

                            • thejq
                              Solar Fanatic
                              • Jul 2014
                              • 599

                              #15
                              One thing you might want to consider is tilt mount, so you get either south, or south west exposure from a SE facing roof. It has been talked about many times but I'm not sure about the cost.
                              16xLG300N1C+SE6000[url]http://tiny.cc/ojmxyx[/url]

                              Comment

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