Announcement

Collapse
No announcement yet.

Hybrid Systems w/ Peak-Shaving & Equipment Selection

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Hybrid Systems w/ Peak-Shaving & Equipment Selection

    Hello everyone and thank you very much for your time.

    we are in the early planning stages for a hybrid system but cannot find a particular brand of equipment that fits my needs, everything keeps falling back to Enphase however they don't quite fit the bill.

    Our current goal is to install a small 2.8kw system consisting of 8 panels rated at 350 watts. We will use this small installation to get our homes infrastructure in place and ready for future upgrades to the total system size as well as recuperate funds for this next round of upgrades. The idea is to use this system for around 6 months then add another 2.8kw worth of 350 watt panels. Using this strategy we can save money for the next round of upgrades and each period of 12 months can result in faster savings due to an ever decreasing utility bill. This cycle would continue until the entire system reaches a "Net Positive" state somewhere in the 20-30kw range.

    The current issue is selecting the proper equipment to fit our needs, as this entire installation will take place over the course of 4 years we want to make sure everything is planned properly from the beginning. Current brands of equipment available seem to provide an entire ecosystem of products which doesn't allow interoperability between other brands so this makes it even more difficult to select equipment, for example you wouldn't want to end up with having two different web portals to manage one system after using one brand of inverters with another brands charge controllers.

    Our ideal system has the following features:
    1. Connected to the grid to export excess energy.
    2. Allow AC-Coupling of a *CUSTOM* designed battery banks.
    3. Support Peak-Shaving to offset grid usage whenever our demand is higher than the panels are capable of putting out.
    4. Micro-Inverters or DC-Optimizers would be a major selling point however using multiple smaller strings of 4 panels should eliminate this need almost completely
    5. Backup power when the grid is down would be nice but it's not essential.

    We would love to go with Magnum however it doesn't seem like they offer any sort of advanced power management such as Peak-Shaving and this is a deal breaker.
    Solar Edge would almost fit the bill however they only appear to support LG or Tesla batteries.
    Enphase would be the best route simply due to their smaller upfront cost for each micro-inverter and the simplistic installation, but they too only support their own proprietary batteries.
    Schneider Electric looks promising, they appear to do everything we require, except maybe point #5 but again that's not essential. We don't like not having micro's or optimizers nor can we find any documentation on how many individual strings can connect to a single inverter.

    The best course of action may to drop the fantasy of a custom battery bank and just go with Enphase, all roads seem to lead to this destination.

    Can anyone suggest other brands that might fit our wants and needs? Maybe someone can educate us on other routes that can be taken to add Peak-Shaving to a system that doesn't directly support it? We want to explore every option available so we can plan and install the best system we can.

    Thank you again for your time and I hope you all have a wonderful day!

  • #2
    Your looking at a $50k-$60k for a 20/30kw system after credits am I hearing you right.
    25kW-Solar-Panel-Cost-System-Infographic.png
    Last edited by Paul Land; 12-18-2018, 11:53 AM.

    Comment


    • #3
      I'd suggest you become a lot more informed about the limitations, costs and availability of equipment as well as the capabilities of PV, on grid, off grid and battery systems before you start any preliminary planning or design, and definitely before you buy any equipment or talk to vendors.

      From what you've written so far it appears to me that you are ill informed and need a lot more self education. Start by learning that not using electricity is a lot more cost effective than buying it from a POCO, which, depending on your time frame to cost effectiveness, is often less expensive than getting it via grid tied PV generation, and WAY less expensive (at least at this time) than off grid generation and storage.

      Grid power is still the way of choice and the method to beat, as well as the most reliable and lowest cost way to supply an electric load to a residence for most, but perhaps not every residential application, at least in N.America. It is still the way against which all other methods are compared. Residential PV may be as cost effective in more situations than in the past, but still not for every application, particularly as f(the length of time to cost effectiveness).

      Residential battery systems are still evolving. Hype abounds from the green press and those with $$ to make from the solar and energy ignorant. They are not cost effective at this time. Big time Caveat Emptor on that one.

      Adding to existing systems sounds like a good idea that experience often shows to be not the best and often far from the best way to go.

      If this is for a single residence and unless you're WAY north or south of the equator, and/or your use is huge for a residential application, a 20 kW system is way above normal size. Also, a 10 kW size range tells me you need to specify your loads and needs better or more tightly.

      Start by buying or downloading a copy of "Solar Power Your Home for Dummies". Then, running PVWatts for your location after you read the help screens a couple of times.

      BTW, if you are in the U.S., know that the solar tax credits are being reduced/phased out.

      Welcome to the neighborhood and the forum of few(er) illusions.

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

      Comment


      • #4
        We have done a lot of research into costs and effectiveness of a solar system over the past few years and keep regularly informed about changes in the industry. I personally have the knowledge and confidence in my skillset to be able to do all the labor required to design and install the system, this includes everything from obtaining the equipment and proper permits all the way to mounting the panels and electrical work. Doing the labor ourselves will remove a big portion of the overall cost.

        I'm here looking for outside advice and knowledge into the different equipment manufacturers currently available today as there are quite a few out there and I have inevitably not discovered them all. I had hoped in posting what we wanted to achieve from a system would allow others to weigh in on what equipment they might use in such a scenario and better equip us in making a final decision. All things though, especially cost, point to Enphase.

        The current excel spredsheet we have setup to give a very rough estimate of costs that have been figured up so far total out at $20,863 for a 21,000kwh system. This is a very rough estimate as it only includes cost of panels, enphase inverters, and complete racking system. Keeping to our 2.8kw initial install figure comes to a total of $2,805. Again this doesn't include permits, additional conduit, breaker boxes, circuit breakers, etc. Once this infrastructure is in place, adding more panels down the line should be a little more straightforward. This estimate also does not include the price of batteries which if we end up going the Enphase route, will add $13,499 to the overall system cost for 10kwh using today's prices.

        Of course a 100% off-grid system exponentially increases the cost of the system. The idea is to stay grid-tied indefinitely as you never know what your power usage will be in the future, adding electric vehicles, more household members, etc.. will increase your total power demand and these are variables you cannot calculate out ahead of time. One could always scale their system to be 2x or 3x to give a buffer for future power demands however we can sleep sound knowing the grid is always there in case the solar system cannot keep up with demand.

        We've already taken measures to reduce our power consumption in the building, LED's in every light fixture, adjusted HVAC temperatures, energy efficient hot water heater, even down to the point of 1.25gpm shower heads to consume less hot water when we use it. These savings are however dwarfed in comparison to the amount of power the small datacenter in our basement consumes. Aside from wanting to reduce our carbon footprint, the amount of server equipment running in our basement is the main driving force behind the push to solar.

        As a side note, It is extremely unfortunate that the solar tax credit is being phased out starting 2020 and completely gone by 2022. I hope this doesn't slow the progress of solar around the country. Get it while it's hot

        I would like to get some more opinions and possible alternatives to using Enphase.
        Thank you again everyone.

        Comment


        • #5
          Originally posted by KKlouzal View Post
          We have done a lot of research into costs and effectiveness of a solar system over the past few years and keep regularly informed about changes in the industry. I personally have the knowledge and confidence in my skillset to be able to do all the labor required to design and install the system, this includes everything from obtaining the equipment and proper permits all the way to mounting the panels and electrical work. Doing the labor ourselves will remove a big portion of the overall cost.

          I'm here looking for outside advice and knowledge into the different equipment manufacturers currently available today as there are quite a few out there and I have inevitably not discovered them all. I had hoped in posting what we wanted to achieve from a system would allow others to weigh in on what equipment they might use in such a scenario and better equip us in making a final decision. All things though, especially cost, point to Enphase.

          The current excel spredsheet we have setup to give a very rough estimate of costs that have been figured up so far total out at $20,863 for a 21,000kwh system. This is a very rough estimate as it only includes cost of panels, enphase inverters, and complete racking system. Keeping to our 2.8kw initial install figure comes to a total of $2,805. Again this doesn't include permits, additional conduit, breaker boxes, circuit breakers, etc. Once this infrastructure is in place, adding more panels down the line should be a little more straightforward. This estimate also does not include the price of batteries which if we end up going the Enphase route, will add $13,499 to the overall system cost for 10kwh using today's prices.

          Of course a 100% off-grid system exponentially increases the cost of the system. The idea is to stay grid-tied indefinitely as you never know what your power usage will be in the future, adding electric vehicles, more household members, etc.. will increase your total power demand and these are variables you cannot calculate out ahead of time. One could always scale their system to be 2x or 3x to give a buffer for future power demands however we can sleep sound knowing the grid is always there in case the solar system cannot keep up with demand.

          We've already taken measures to reduce our power consumption in the building, LED's in every light fixture, adjusted HVAC temperatures, energy efficient hot water heater, even down to the point of 1.25gpm shower heads to consume less hot water when we use it. These savings are however dwarfed in comparison to the amount of power the small datacenter in our basement consumes. Aside from wanting to reduce our carbon footprint, the amount of server equipment running in our basement is the main driving force behind the push to solar.

          As a side note, It is extremely unfortunate that the solar tax credit is being phased out starting 2020 and completely gone by 2022. I hope this doesn't slow the progress of solar around the country. Get it while it's hot

          I would like to get some more opinions and possible alternatives to using Enphase.
          Thank you again everyone.
          SMA is a great choice and change out HVAC to geothermal,new systems sip power. Mine (geo) runs @ 400w-1300w Vs 3000+w Old HVAC Sys.

          Comment


          • #6
            Originally posted by KKlouzal View Post
            Hello everyone and thank you very much for your time.



            Our ideal system has the following features:
            1. Connected to the grid to export excess energy.
            2. Allow AC-Coupling of a *CUSTOM* designed battery banks.
            3. Support Peak-Shaving to offset grid usage whenever our demand is higher than the panels are capable of putting out.
            4. Micro-Inverters or DC-Optimizers would be a major selling point however using multiple smaller strings of 4 panels should eliminate this need almost completely
            5. Backup power when the grid is down would be nice but it's not essential.


            The best course of action may to drop the fantasy of a custom battery bank and just go with Enphase, all roads seem to lead to this destination.

            Can anyone suggest other brands that might fit our wants and needs? Maybe someone can educate us on other routes that can be taken to add Peak-Shaving to a system that doesn't directly support it? We want to explore every option available so we can plan and install the best system we can.

            Thank you again for your time and I hope you all have a wonderful day!
            ok a few issues here.

            First WHY the want for AC- Coupled storage? that seems odd. DC coupled is more efficient and cheaper.
            What exactly is a CUSTOM designed battery bank?

            Why have you not included OutBack Power?

            Also Almost ANY inverter system can be AC coupled. That is much more dependent on the bimodal or hybrid inverter that is used than the grid tie.

            Have you considered a loan? it is far far cheaper to install 10kW at once than to try to do it in 2.5kW chunks repeatedly.
            You seem to indicate that you managed to get pricing on the bulk of the equipment to about $1/w which seem pretty low if it include racking, mounts, inverter, and PV modules.
            Last edited by ButchDeal; 12-18-2018, 03:39 PM.
            OutBack FP1 w/ CS6P-250P http://bit.ly/1Sg5VNH

            Comment


            • #7
              Originally posted by KKlouzal View Post
              The current excel spredsheet we have setup to give a very rough estimate of costs that have been figured up so far total out at $20,863 for a 21,000kwh system. This is a very rough estimate as it only includes cost of panels, enphase inverters, and complete racking system. Keeping to our 2.8kw initial install figure comes to a total of $2,805. Again this doesn't include permits, additional conduit, breaker boxes, circuit breakers, etc. Once this infrastructure is in place, adding more panels down the line should be a little more straightforward. This estimate also does not include the price of batteries which if we end up going the Enphase route, will add $13,499 to the overall system cost for 10kwh using today's prices.
              Does you estimate include flashed mounts for the racking?
              how about the (expensive and proprietary) enphase cabling to connect the micro inverters?k
              You can't just double the size of an array much less triple or quadruple the size. The AC combiner, interconnect all have to be sized for that full size. The interconnect agreement will have to be redone with each expansion and likely not to your advantage.

              you mentioned 21,000kwh system? is this your expectation for annual production? what size (in kW) is the system?

              Originally posted by KKlouzal View Post
              We've already taken measures to reduce our power consumption in the building, LED's in every light fixture, adjusted HVAC temperatures, energy efficient hot water heater, even down to the point of 1.25gpm shower heads to consume less hot water when we use it. These savings are however dwarfed in comparison to the amount of power the small datacenter in our basement consumes. Aside from wanting to reduce our carbon footprint, the amount of server equipment running in our basement is the main driving force behind the push to solar.
              LEDs help but are a very small portion of consumption in most homes.
              Is your hotwater heater electric? you might try lowering the water temperature in the heater. That will have a bigger effect.

              So small data center in your basement, what exactly are we talking here? there are much more efficient servers that can be use, and the heat can be let to ride a lot higher than previously though.
              OutBack FP1 w/ CS6P-250P http://bit.ly/1Sg5VNH

              Comment


              • #8
                I did forget the Enphase Trunk Cables in the rough estimate, adding those brings the 21kw system up to $21,731 and the 2.8kw system to $2,921. This includes the panels, rails, panel clamps, rail feet, inverter mounts. I might be missing bolts that connect the rail feet to the legs, the listing wasn't clear if they were included with the feet or not, if not it might add $65 at most. Again that's just everything needed at the roof level. All other electrical conduit, breaker boxes, breakers, wire, permits not included however most of this should be a one-time cost aside from more wire/conduit/breakers as long as the initial install is done with future expansion in mind and a rough idea of what the final product will be.

                I did not pay much attention to DC-Coupled battery storage, after a few hours of reading it seems like this is indeed the superior method for storage. It would provide all the advanced features such as Peak-Shaving/Load-Shifting since the batteries are now between the panels and inverters. Not to mention the increase in efficiency since were not going DC->AC->DC->AC to charge/drain the batteries.
                These key features we were looking for are automatically provided with a proper DC-Coupled system:
                1. As long as the power drain on the system (from the inverters) is less than the current power output of the panels then the batteries will charge
                2. If the batteries are full then power will be exported to the grid.
                3. If your power drain (from the inverters) is greater than what the panels are producing then it will drain from the batteries up to the maximum supported wattage of the inverters.

                So as long as you size your inverters to handle the highest load you expect to pull from the building then the batteries can Peak-Shave and Load-Shift and now you can apply this system to a much broader range of inverter brand/manufacturers.

                Going to read up on SMA and OutBack more in depth, a lot of people are using Outback systems and SMA SunnyBoy, both are well known names in the industry and they should have been looked into further already, shamefully they weren't.

                As far as "custom batteries", the ability to design our own battery bank to use with the system, selecting batteries we feel are appropriate for the system, looking into different manufacturers and finding one that makes us feel comfortable that they will last for years to come. Li-On would be the optimal choice with whatever manufacturer is used but without proper care and consideration put in place these are essentially a ticking time bomb. We've had our eye on SBS-Batteries for a while.

                I'm going to need to do more research into exactly how DC-Coupled systems are wired up so I can have a better understanding of the big picture, most information I can find deals with Utility-Scale production and differences beween AC/DC coupling.

                I want to thank everyone again for their suggestions and input it has helped a lot already.

                Comment


                • #9
                  Micronverters wire directly to PV panels and can provide no power when the grid is down or at night

                  String inverters generally run off 500VDC from the panels. and provide no power when the grid is down or at night

                  Hybrid inverters run off battery voltage (48V in your case) and the XW series from Schneider (I can speak about them because I have them) can load shave or sell excess AND run without grid power. They do require solar Charge Controllers to charge the batteries. The XW line also has internal transfer switches and a Generator AC2 input.

                  You need to research this more before you purchase any gear. Download the manuals, read them till you understand them and then decide on what gear.
                  Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
                  || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
                  || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

                  solar: http://tinyurl.com/LMR-Solar
                  gen: http://tinyurl.com/LMR-Lister

                  Comment

                  Working...
                  X