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  • #16
    Originally posted by BuddLakeSE View Post
    SunEagle, thanks for the explanation.

    To all,

    As way of intro...
    I own (not lease) a grid-tied 9.3kW system, with 27 x SunPower X21-345w modules, SolarEdge Optimizers and inverter (SE6700).
    The install was completed in early December 2014, but it took the local utility until mid-January 2015 to install the net metering for official startup.

    (BTW, I would have joined solarpaneltalk.com back then, but just discovered it!)

    Annual Production so far has been: 10.5MWh (2015), 11.0MWh (2016), 10.0MWh (2017).
    Only a guess, but I suspect the 9-10% dropoff last year was mainly weather related - it was a really overcast winter (and continues to be in 2018 ).

    Besides the FIT tax credit and a much lower monthly electric bill, in NJ we get awarded 1 SREC (Solar Renewable Energy Certificate) for each MWh we produce.
    SRECs can then be sold on a PJM-run marketplace - current bid price (today) is $225 per, although it can vary quite a bit (e.g. $172 last October).

    I expected and still hope to get ROI in the first 6-7 years, and after that it's all gravy. Of course, if new models of panels hit 35% efficiency, I'll consider upgrading, but ...
    Annual output of +/5% due to weather alone is to be expected. +/-10% is also pretty common. That's probably where most of the 0.5 MWh increase 2015 to 2016 came from as well as the 1.0MWh increase 2016 to 2017. Solar generation is much more variable than fossil fuel, nuke or hydro generation.

    Unless PV panels change materials and processes, the thermodynamic limit for currently available and marketed panels is ~~ 30-32% or so. Don't expect that to be reached in a production model, reliable fashion for some years.

    You have about the most (area) efficient units available today or for the last few years at ~ 21-22%. In spite of what Sunpower would like to have us all believe, efficiency is not necessarily the name of the game in PV. It's more about a safe and reliable way to get the most bang for the buck.

    Too bad you didn't find SPT before you bought Sunpower. Your ROI would be about 20% higher today with equally productive, fit for purpose but less expensive equipment.

    Welcome to the neighborhood.

    BTW, what's your zip (in the NE maybe ?) and array orientation ? 11,000 kWh/yr. from a 9.3 kW system seems a bit on the light side. Any shading ?

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    • #17
      If his name indicates where he lives I would say we might have been neighbors at one time. I lived in Budd Lake NJ on Tulip Ave.back in the early 1980's. Then moved to Sucasunna for a few years before I headed to Florida.
      Last edited by SunEagle; 04-06-2018, 09:17 PM.

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