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  • New Grid Tie In System Proposals in Colorado

    I have been interested in Solar for a few years, and our last home was not a good candidate for numerous reasons. Our current home, on the other hand, is a much better candidate so I have been doing some data gathering, ran PVWatts various times/ways, and submitted requests of bids. (I even played with SAM for a bit haha.)

    Our home has a flat roof (new white 60mil TPO), so we will be using a ballast system (such as dynomaxx with a 10 degree tilt), and all panels will be facing south. There is very little shade concerns based on what two installers were indicating on site visits.

    We used just a tad bit more than 14500 kwh over the last twelve months, and I was looking to install a system that would meet this need. Based on my PVWatt runs, a system between 9.5 - 9.9 kw should be sufficient to generate between 13500 - 14500 per year here in Colorado. The system would be on a net meter plan.

    I got a bunch of bids, though very few from the big solar folks as they don't seem to install on flat roofs in my area.

    I have been getting quotes from $2.75/watt - $3.80/watt, for systems primarily in the 9.5 - 9.9kw, The majority of the bids were in the $2.75 - $3.30, though the highest bid ($3.80/watt) was for a system providing 6.7kw haha, and they tried to sell it has providing enough to meet my needs as they would make my house more efficient to reduce my electrical usage. (They didn't get very far in my process.)

    I found 2 installers that I really liked, both had great reviews, where local, and didn't try to sell me things I didn't need. (not sure how many companies tried to sell me a nest thermostat to help improve efficiency with their systems.). They were more than happy to build systems based on different panels (initially I started looking at LG 360's, and then wanted to look at saving some money.)

    The two bids from them that I was most interested in are basically the same systems, but their prices were different. (The higher price is from the company that is bigger, and I suspect they have higher costs, but they are also the ones I enjoyed working with the most.)

    Installer 1
    $2.75/watt (before FTC)
    33 SolarWind 300 watt panels, or 31 QCells 320 watt panels (9.9kw systems)
    IQ7 micro inverters

    Installer 2
    $2.90/watt (before FTC)
    33 SolarWind 300 watt panels (9.9kw system)
    IQ7 micro inverters

    Both of the installers were basically the same price on the LG 360 panels

    $3.18 - $3.20/watt (before FTC)
    27 LG 360 watt panels (9.72kw system)
    IQ7 micro inverters

    Both installers preferred the enphase micro's, but could also use SE 10000 inverter with power optimizers. (Though their pricing is the same.)

    Just wanted to get folks thoughts on the price / watt listed here for the equipment in question.

    Thanks!

  • #2
    I am in NJ, i have 35 LG 320W with SE 10000... installed on 5/2017 for $3.07 per Watt... 11.2kW system

    Comment


    • #3
      Originally posted by Jayc5627 View Post
      I am in NJ, i have 35 LG 320W with SE 10000... installed on 5/2017 for $3.07 per Watt... 11.2kW system
      I should check on those LG 320's and see what the price quote would be from these installers.

      Comment


      • #4
        Going rate in my neck of the woods is ~2.50/w for a turn key installation. I'd say they aren't too far off but not familiar with your area.

        I opted for doing the installation myself which my county and POCO allows... cut the cost to ~$1/w.. however there is a lot of leg work to do.
        Last edited by Mr4btTahoe; 04-23-2018, 11:25 AM.

        Comment


        • #5
          In spite of being overpriced, and without particulars I'll not defend them, but the outfit selling conservation with PV combo (if that's what it is) uses an idea that makes sense in most cases. They may just be ripping you off, but compare their overall annual elec. bill reduction estimates with the others. It's almost always more cost effective to reduce a load before PV than to simply throw more PV at a bill that's not been reduce by conservation measures.

          As for ballasted systems on what I'm assuming is a horizontal, or mostly horizontal roof (most roofs are flat, just not horizontal), you'll be well advised to be very careful on that. First, there may be building codes to deal with. Check it out very carefully before you proceed.

          Then, know that the ballast mass may be substantial - and create forces and moments much greater than you may think and/or more than were considered in the original design. Also, most any ballasted system must usually still be anchored in some fashion so it doesn't creep around - and it will if not anchored in some way. Not much (maybe), but some. Such anchorage, while not as substantial as non ballasted anchorage, will usually negate most of the perceived advantage of a ballasted - that is - not requiring any penetrations in a horizontal roof. Unless very carefully designed, and for a lot of other reasons besides mentioned here, ballasted systems and flat roofs are not a good marriage.

          Even tilted systems on mostly horizontal roofs that are anchored and non ballasted need more consideration because of possible imposed moments from wind uplift or downward forces exerted on a horizontal or mostly horizontal roof that can be in excess of moments imposed on tilted roofs, including the idea of (not so) occasional forces and moments of a more or less cyclic or repeating nature from wind. Just know that there may be more to mounting a system on a flat roof than you may be aware of and ballasted systems may not be the best way to go.

          You sure about that PVWatts output ? What orientation are you using ? South, but same tilt as the roof ? You'll get a smaller array with a higher tilt. If in rows, the row pitch will need to be > than the significant panel length (that is, the long panel side if in portrait, the short panel side if in landscape), but in the end, the system output from the available roof footprint will be about the same for a smaller array but tilted more than the roof.

          Why are you even considering micros when you have no shade problems ? IMO and that of some others, you're building in problems for no need or advantage and probably paying more for the privilege.

          Comment


          • #6
            Originally posted by J.P.M. View Post
            In spite of being overpriced, and without particulars I'll not defend them, but the outfit selling conservation with PV combo (if that's what it is) uses an idea that makes sense in most cases. They may just be ripping you off, but compare their overall annual elec. bill reduction estimates with the others. It's almost always more cost effective to reduce a load before PV than to simply throw more PV at a bill that's not been reduce by conservation measures.
            It was definitily the latter (i.e. trying to sell a lower kw based system by providing efficiencies that would never be possible with just a nest thermostat and some insulation.) I have no attic to insulate, and what space that is between my ceiling and TPO roof already has insulation, as well as another 3 inches of insulation installed when I had the roof redone due to a massive hail storm.

            The home currently has efficient windows, lots of insulation, smart thermostats, etc. My actual heating (water boiler) and cooling needs are a lot less than my previous home, where I only need to run of built in AC units for short periods in the summer to keep the whole house cool. (it is approx a 3k ranch, no basement.). The main energy usage in my home is my dryer and one of my electric water heaters that I cannot convert to gas without some serious expense to run ducting, gas lines, etc., I am planning on swapping it out with a heat pump electric water heater in the future, but will still need to run some ducting due to its location to get the best efficiency out of it.

            Originally posted by J.P.M. View Post
            As for ballasted systems on what I'm assuming is a horizontal, or mostly horizontal roof (most roofs are flat, just not horizontal), you'll be well advised to be very careful on that. First, there may be building codes to deal with. Check it out very carefully before you proceed.

            Then, know that the ballast mass may be substantial - and create forces and moments much greater than you may think and/or more than were considered in the original design. Also, most any ballasted system must usually still be anchored in some fashion so it doesn't creep around - and it will if not anchored in some way. Not much (maybe), but some. Such anchorage, while not as substantial as non ballasted anchorage, will usually negate most of the perceived advantage of a ballasted - that is - not requiring any penetrations in a horizontal roof. Unless very carefully designed, and for a lot of other reasons besides mentioned here, ballasted systems and flat roofs are not a good marriage.

            Even tilted systems on mostly horizontal roofs that are anchored and non ballasted need more consideration because of possible imposed moments from wind uplift or downward forces exerted on a horizontal or mostly horizontal roof that can be in excess of moments imposed on tilted roofs, including the idea of (not so) occasional forces and moments of a more or less cyclic or repeating nature from wind. Just know that there may be more to mounting a system on a flat roof than you may be aware of and ballasted systems may not be the best way to go.
            My roof is a completely horizontal flat roof, with minimal tilt to allow for water to flow off. The goal for using a ballasted system was two fold, one to reduce the chance of leaks due to anchoring, and second to keep my roof warranty, since it is just eight months old. Each installer I talked too who came out to check the roof did not have concerns about using a ballasted system for a few reasons. The roof is very large from a sqft perspective, and they are able to easily spread out the panels to reduce the amount of weight in each section Based their review of how the roof was constructed, they did not see concerns of the additional weight, but obviously each bid included an engineers review to verify weight compliance, etc.

            Originally posted by J.P.M. View Post
            You sure about that PVWatts output ? What orientation are you using ? South, but same tilt as the roof ? You'll get a smaller array with a higher tilt. If in rows, the row pitch will need to be > than the significant panel length (that is, the long panel side if in portrait, the short panel side if in landscape), but in the end, the system output from the available roof footprint will be about the same for a smaller array but tilted more than the roof.

            Why are you even considering micros when you have no shade problems ? IMO and that of some others, you're building in problems for no need or advantage and probably paying more for the privilege.
            I am pretty comfortable with the PVWatts output I was running. I used a south orientation (180 degrees) as the installers were able to place all panels in that direction. I also made sure the tilt was set to 10 degrees. I did both open rack and roof attached. Based on the instructions, the flat roof install closer resembled the open rack option, but I ran both to see the difference, which was a couple of hundred kwhs I believe. Because of the wind load concerns, 10 degrees seems to be the most common tilt angle ballasted systems come with. The systems were apparently designed to withstand the wind load requirements for the area, which as you mentioned is very very important! I spent some time reviewing ballasted system offerings, and most of them all are at a default of 10 degrees, with some that go up to 12 - 15 degrees tilt, but those weren't very common. In order to get more of a tilt, the system would have to be a penetration based system.

            As for the micros vs SE, I see the pros and cons of both, and 90% of the bids I got all defaulted to using micros. I specifically asked each installer what the cost difference would be to using SE, and none of them came back with a lower cost. While I obviously can dictate whatever technology I want to use, and I haven't fully made a decision yet, but I do have a concern about future support, as the majority of the solar installers in the area seem to prefer micros, Even the larger named installers (that actually worked on flat roofs) where defaulting to Micros. Only 1 of my bids defaulted to an SE7600 (non HD), that even based on SE's design tool wasn't the correct model to use based on the size of the system they proposed. It would be a whole lot easier to use SE if that was the default tech being implemented in the area, but I am just not seeing it on the 10 or so bids I got. (Its almost like deciding to buying a foreign car, importing it, and then trying to get support locally where primarily only domestic cars are available and serviced. Ok, that might be a stretch of an example haha ) That being said, all of the installers did indicate they could do an SE based system, and I suspect that because they don't do it as often in the area, that is why the cost was the same.

            Comment


            • #7
              Originally posted by kbonnel View Post

              It was definitily the latter (i.e. trying to sell a lower kw based system by providing efficiencies that would never be possible with just a nest thermostat and some insulation.) I have no attic to insulate, and what space that is between my ceiling and TPO roof already has insulation, as well as another 3 inches of insulation installed when I had the roof redone due to a massive hail storm.

              The home currently has efficient windows, lots of insulation, smart thermostats, etc. My actual heating (water boiler) and cooling needs are a lot less than my previous home, where I only need to run of built in AC units for short periods in the summer to keep the whole house cool. (it is approx a 3k ranch, no basement.). The main energy usage in my home is my dryer and one of my electric water heaters that I cannot convert to gas without some serious expense to run ducting, gas lines, etc., I am planning on swapping it out with a heat pump electric water heater in the future, but will still need to run some ducting due to its location to get the best efficiency out of it.



              My roof is a completely horizontal flat roof, with minimal tilt to allow for water to flow off. The goal for using a ballasted system was two fold, one to reduce the chance of leaks due to anchoring, and second to keep my roof warranty, since it is just eight months old. Each installer I talked too who came out to check the roof did not have concerns about using a ballasted system for a few reasons. The roof is very large from a sqft perspective, and they are able to easily spread out the panels to reduce the amount of weight in each section Based their review of how the roof was constructed, they did not see concerns of the additional weight, but obviously each bid included an engineers review to verify weight compliance, etc.



              I am pretty comfortable with the PVWatts output I was running. I used a south orientation (180 degrees) as the installers were able to place all panels in that direction. I also made sure the tilt was set to 10 degrees. I did both open rack and roof attached. Based on the instructions, the flat roof install closer resembled the open rack option, but I ran both to see the difference, which was a couple of hundred kwhs I believe. Because of the wind load concerns, 10 degrees seems to be the most common tilt angle ballasted systems come with. The systems were apparently designed to withstand the wind load requirements for the area, which as you mentioned is very very important! I spent some time reviewing ballasted system offerings, and most of them all are at a default of 10 degrees, with some that go up to 12 - 15 degrees tilt, but those weren't very common. In order to get more of a tilt, the system would have to be a penetration based system.

              As for the micros vs SE, I see the pros and cons of both, and 90% of the bids I got all defaulted to using micros. I specifically asked each installer what the cost difference would be to using SE, and none of them came back with a lower cost. While I obviously can dictate whatever technology I want to use, and I haven't fully made a decision yet, but I do have a concern about future support, as the majority of the solar installers in the area seem to prefer micros, Even the larger named installers (that actually worked on flat roofs) where defaulting to Micros. Only 1 of my bids defaulted to an SE7600 (non HD), that even based on SE's design tool wasn't the correct model to use based on the size of the system they proposed. It would be a whole lot easier to use SE if that was the default tech being implemented in the area, but I am just not seeing it on the 10 or so bids I got. (Its almost like deciding to buying a foreign car, importing it, and then trying to get support locally where primarily only domestic cars are available and serviced. Ok, that might be a stretch of an example haha ) That being said, all of the installers did indicate they could do an SE based system, and I suspect that because they don't do it as often in the area, that is why the cost was the same.
              As you see fit. I'd be skeptical of what vendors with skin in the game had to say about ballasted systems or anything else for that matter had say.

              As for Solar edge vbs. micros, with no shade and south facing, why not just a string inverter ? Simpler so fewer electronics to screw up, about the same production in a no shade environment and cheaper.

              As for a 10 degree tilt, there's a reason for that. MAYBE less uplift ,making an bit easier case (and lower load) for ballast. Down side is lower output per panel area. Also, don't forget to consider the idea of snow removal. In CO, chances are you will get snow, and it will be more of a hassle to remove the lower the tilt. Believe it. Something else vendors don't talk about much.

              Lastly, as I mentioned, and what vendors will not tell you, is that ballasted system will move. Maybe not much, but it doesn't take much to cause problems. To restrict/control that movement will most likely take some roof penetration(s), or guying, which raises real safety issues and anchorages for the guy fixations which may be roof penetrated anyway. There are ways to penetrate a horizontal roof and have a reasonable chance of a fit for purpose fixation that can be inspected and maintained to provide a leak tight seal.

              Take what you want of the above. Scrap the rest.

              Comment


              • #8
                Originally posted by J.P.M. View Post

                As you see fit. I'd be skeptical of what vendors with skin in the game had to say about ballasted systems or anything else for that matter had say.

                As for Solar edge vbs. micros, with no shade and south facing, why not just a string inverter ? Simpler so fewer electronics to screw up, about the same production in a no shade environment and cheaper.

                As for a 10 degree tilt, there's a reason for that. MAYBE less uplift ,making an bit easier case (and lower load) for ballast. Down side is lower output per panel area. Also, don't forget to consider the idea of snow removal. In CO, chances are you will get snow, and it will be more of a hassle to remove the lower the tilt. Believe it. Something else vendors don't talk about much.

                Lastly, as I mentioned, and what vendors will not tell you, is that ballasted system will move. Maybe not much, but it doesn't take much to cause problems. To restrict/control that movement will most likely take some roof penetration(s), or guying, which raises real safety issues and anchorages for the guy fixations which may be roof penetrated anyway. There are ways to penetrate a horizontal roof and have a reasonable chance of a fit for purpose fixation that can be inspected and maintained to provide a leak tight seal.

                Take what you want of the above. Scrap the rest.
                I very much appreciate the information, none of it gets scrapped, just prioritized based on my situation. None of the installers in my area wanted to talk about, or offer, just doing a string inverter. As I am not a Solar PV expert (if I was, I would probably be in the business ), one must rely on the experts within the region who offer, install, and support the systems. If I was doing this myself, supporting it myself, etc., I would seriously consider just a string inverter setup.

                In my situation, if I want to consider solar, compromises have to be made to any system. Having a flat roof limits my ability to have a perfectly tilted panel for the most efficiency (I believe it would be approx 40 degrees per PVWatts runs), and it would provide and additional (approx.) 1500 kwh per year vs 10 degrees. Though this would most definitely not be a ballast system, and I have no idea what would be needed to support this on a flat roof. Jumping up to a 15 degree tilt would add approx 450 kwh per year to the system, but again, not sure what would be needed to support this from a mounting perspective. As such, I defer to what the local installers recommend, based on what they continuously deeply within the area when doing ballast systems, which is 10 degrees. Obviously right off the bat, producing more kwh per year would mean I could save money on less panels, but how much of that savings would go to supporting the higher tilt (e.g.no warranty on roof due to penetrations, different racking system, etc.) Compromises. Definitely understand regarding the snow coverage, but there isn't a lot I can do about that other than wait for it too melt, which usually happens fast in Colorado. Of course, having a completely flat roof would make it "easier" to properly wipe the snow off assuming it was safe enough to get on the roof. Again, Compromises. Since I have not signed a contract yet, I am attempting to go into this with my eyes wide open, understanding the potential pitfalls (tilt, snow, ballast, etc.) with the pros (no shade, tons of sun in Colorado year round, having a very close to 100% offset of my electricity, increased equity, continued Tax credit, cost of my electricity over the last 12 months and the cost of the Solar, etc.)

                I most certainly will ask about the movement of the ballast systems to understand what kind of damage that may cause, etc.

                Comment

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