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  • Greetings from Brazil

    Hello all, I live in Brasilia, capital of Brazil. I am not exactly new to this forum because have reading it for the last six months.

    But the reason I come now is that today my on-grid PV system finally started producing, which makes me proud.

    My system consists in 18 x 275W CS6K Canadian modules, divided in 2 strings of 9, totaling 4.95kW DC peak and 1 Fronius PRIMO 5.0-1 inverter.

    Modeling this system in SAM resulted in 7,440kWh/y. Brasilia is located at latitude 16 degree south and 3,000ft altitude. The estimated efficiency of the system is 4.12kWh/kW. This production offsets more than 100% of my current consumption, but my consumption is still increasing and I am planning buying a electric car in a few years.

    The overall cost, including no only these equipments but wires, mounts, installation and project for POCO, was US$ 1.90/W.

    This is the final cost for me since there is no rebates. But there are incentives from the government like exemption for importation and sale taxes on PV generators.

    Here POCO uses netmetering model, so all energy injected on grid and not used becomes kWh credits. This credits lasts for 60 months, which after that it expires. The compensation is made on a 1 to 1 basis.

    The investment is estimated to be paid in 8 years.
    Last edited by rcmc; 12-02-2017, 06:04 AM.

  • #2
    U.S. $ ?

    $1.90 for material and labor = turnkey or material only ?

    Tilt/Azimuth ? If close to horizontal, know that array cleanings will be required much more frequently. Horizontal or close to horizontal arrays turn into mud pans in short order.

    7,440 kWh/yr./4.95 STC kW = 1500 kWh/yr. per STC kW. While not bad, I'd have thought Brasilia would yield a higher specific annual output. What are the temps. like ?

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    • #3
      Hi JPM, I've read lots of posts from you. I even downloaded and read solar power for dummies, although I am not new to solar energy.

      My contract was turnkey. The only thing to do was paying it in 4 instalments. After the project was aproved by POCO, my vendor could not order the panels and the inverter sold to me so they offered me an upgrade. My panels were changed from 270W to 275W and the inverter from 4000W to 5000W, both from the same line of products.

      The price is already in US$.

      In the pictures attached you can see panels arrays. One array is azimute 33 degree and the other is 213. The latter is poorly oriented but was the only place to put 9 panels without shading. SAM showed to me that this array produces 15% less than the other one on a year basis. Both arrays are 17 degree tilted.

      During the days temperature ranges from 70 to 90 degree F throughtout the year. Never snow and there are two clearly seasons, 6 months of rain and 6 month of drought.

      As for the efficiency, if the poor array had the same other orientation the system could produce 7.5% more.

      Now the next step is setup the inverter to push data to pvoutput.

      telhado.PNGEnergia-Fotovoltaica-495-kWp-1-4.jpgEnergia-Fotovoltaica-495-kWp-3-4.jpgEnergia-Fotovoltaica-495-kWp-4.4.jpgEnergia-Fotovoltaica-495-kWp-Capa-2.jpginversor.PNG
      Last edited by rcmc; 12-02-2017, 06:38 AM.

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      • #4
        Here goes my system:

        https://pvoutput.org/list.jsp?id=60164&sid=55836

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        • #5
          Originally posted by rcmc View Post
          Any surprises so far ? Not wishing them on you, but any roof leaks/other problems yet ?

          Respectful suggestion: You may want to consider hosing off the array about every 4 weeks or so during the dry season, or more often if you get a lot of pollen.

          What's the cost of electricity in your area ?

          Thanx for the update.

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          • #6
            No problems with leaking and it rained a lot since installation. The installers broke some tiles, but I had replaces for them.

            In fact, the surprise is positive. As I said the inverter would be of 4,000w and by SAM there would be very few hours of clipping in a year. But I what I see is that the panels can easily surpass that value and sometimes be clipped at 5,000w, the nominal power of the installed inverter. Today generation is a good example. Had I had the 4,000w inverter I would loss a lot of energy.

            No problem with pollen here, but at dry season dirt lays down everywhere. I will have to hose off the array frequently.

            1 Kwh costs US$ 21 cents.

            Comment


            • #7
              Originally posted by rcmc View Post
              No problems with leaking and it rained a lot since installation. The installers broke some tiles, but I had replaces for them.

              In fact, the surprise is positive. As I said the inverter would be of 4,000w and by SAM there would be very few hours of clipping in a year. But I what I see is that the panels can easily surpass that value and sometimes be clipped at 5,000w, the nominal power of the installed inverter. Today generation is a good example. Had I had the 4,000w inverter I would loss a lot of energy.

              No problem with pollen here, but at dry season dirt lays down everywhere. I will have to hose off the array frequently.

              1 Kwh costs US$ 21 cents.
              Thank you. If an install doesn't leak with the first good rain, baring a lot of subsequent foot traffic, it's likely good for the duration.
              A 5 kW inverter seems well suited to the application, particularly given the likely small cost differential in going from a smaller up to a 5 kW inverter.
              Given the PVOutput max power of a bit better than 5 kW +/- some as of late, I suspect a bit of clipping, but relatively minor, particularly with a 4.95 kW STC rating. That max output will probably drop back some as the panels burn in.

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              • #8
                Yes, it is clipping. I keep watching the display and sometimes I see the power reach up 5600w, but only to last 2 seconds and be clipped to 50XX something.

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                • #9
                  Hello everyone, I'm back to update the news about my system. Now it's been 8 months running. Overall, it produced 3% more than what SAM has predicted so far. I am optimistic that will close the first year above the goal.

                  On the night of July 14, I washed the panels for the first time. In fact, I just wet the panels with a hose and did not rub it at all. The panels were all red due to dirt and some poop pigeons stuck. That day, it had been 80 days since the last rain.

                  Regarding production, considering the 12 days before and 12 days after washing, excluding the 17 that was cloudy, production increased 10% on average.

                  You can see this difference in the daily production chart. https://pvoutput.org/list.jsp?id=60164&sid=55836

                  Comment


                  • #10
                    Originally posted by rcmc View Post
                    Hello everyone, I'm back to update the news about my system. Now it's been 8 months running. Overall, it produced 3% more than what SAM has predicted so far. I am optimistic that will close the first year above the goal.

                    On the night of July 14, I washed the panels for the first time. In fact, I just wet the panels with a hose and did not rub it at all. The panels were all red due to dirt and some poop pigeons stuck. That day, it had been 80 days since the last rain.

                    Regarding production, considering the 12 days before and 12 days after washing, excluding the 17 that was cloudy, production increased 10% on average.

                    You can see this difference in the daily production chart. https://pvoutput.org/list.jsp?id=60164&sid=55836
                    Thanx for the update. Hosing about every 4 weeks as you have done ought to help hold the performance penalty from fouling to ~ 2-4 % or so.

                    This is more coincidental that anything else probably, but it looks like your ~ 11.5 weeks of no rain/cleaning and a 10 % performance improvement after cleaning sort of agrees my empirical guesstimate of ~ 1% per week performance reduction in the absence of any cleaning/hosing/rain.

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                    • #11
                      rcmc, I love your set up. If I didn't have a big tree in my back yard, I would have loved to something similar to that. My only options is to mount my panels on the north end of my house, which also seems to get a lot of sun, just not enough like a southern end. Your English is fantastic. Do a lot of people in Brazil speak English or only Portuguese?

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                      • #12
                        Originally posted by J.P.M. View Post

                        Thanx for the update. Hosing about every 4 weeks as you have done ought to help hold the performance penalty from fouling to ~ 2-4 % or so.

                        This is more coincidental that anything else probably, but it looks like your ~ 11.5 weeks of no rain/cleaning and a 10 % performance improvement after cleaning sort of agrees my empirical guesstimate of ~ 1% per week performance reduction in the absence of any cleaning/hosing/rain.
                        During rain season hosing is not necessary, because rarely it takes more than 10 days without raining. But I wish I could hose the panels everymonth during the drought. The problem is climbing on the roof, something I am not really fan of it. I intend to hose the panels only once a year, exactly in the middle of the drought. I am going to estimate the losses of doing this way instead of five monthly hosing during drought.

                        Comment


                        • #13
                          Originally posted by RenewablesRock View Post
                          rcmc, I love your set up. If I didn't have a big tree in my back yard, I would have loved to something similar to that. My only options is to mount my panels on the north end of my house, which also seems to get a lot of sun, just not enough like a southern end. Your English is fantastic. Do a lot of people in Brazil speak English or only Portuguese?
                          It is pretty frustranting not putting the panels at the best location, but notice that half of my panels are headed south, which is unoptimal where I live. Theses southen panels produces 15% less than the northen. But in my case it was take it or leave it. However, in the end what really matters is what much cost the kwh produced. If you are confortable with the price paid for the set up versus the expected production go for it.

                          Most Brazilians don't speak English. It is not taught at regular schools. If you want to learn it have to attend an English school and pay for it.

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                          • #14
                            Originally posted by rcmc View Post

                            However, in the end what really matters is what much cost the kwh produced. If you are confortable with the price paid for the set up versus the expected production go for it.
                            You have just hit the nail on the head. Problem often is that most folks don't know much about what they pay for in terms of long term costs vs. long term costs of other ways to supply electricity.

                            RenewablesRock's posts are probably some of the best examples of that type of ignorance I've seen lately.
                            Last edited by J.P.M.; 08-01-2018, 01:05 PM.

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