This is the winter of my contentment!

jagecjagec Solar Expert Posts: 157 ✭✭
This is a bit of a brag thread.

My grid-tied system was finally commissioned on November 4th of last year, having taken months longer and thousands of dollars more than I had originally planned. I have to admit that I was feeling a little burnt out on solar by the time it was all done. I still don't think that my installer did a very professional job.

But luckily for me, this winter has seen unexpectedly good weather, which meant that the system has been producing far more power than it ought, based on historical data. I haven't paid a penny for electricity since the system was turned on.

If I take the PV-watts estimates for my system and the readings that the Sunny Boy gives me (I write them down at the end of every month), I can calculate my effective derating factor for that month. Of course, I was just hoping to beat the .77 default. Well, my average derating factor for November through February has been 0.96 8)

I am beginning to think that I shouldn't have undersized my inverter as much as I did (4 kW Sunny Boy on 4.95 kW of Canadian Solar panels)!

Too much power (if you're grid tied) is a good problem to have...

Have the rest of you fared unusually well this winter?

Comments

  • peakbaggerpeakbagger Solar Expert Posts: 341 ✭✭✭
    Re: This is the winter of my contentment!

    Dont you love it when a plan comes together!

    What type of panels? if they are amorphous, they have a higher than published efficiency for a few months while they "burn in" so the first winter will have slightly better results then later years. You would also have to factor in the temperature unless the Sunny Boy takes that into account. Ideally a cold clear winter with some snow on the ground with new panels will give you higher than normal readings.

    I expect in Maryland there isnt snow on the ground, so chalk it off on cold temps and clear days.

    Now when you get to the point where you dont record the data, you truly are finished with the system.
  • jagecjagec Solar Expert Posts: 157 ✭✭
    Re: This is the winter of my contentment!

    Panels are polycrystalline, 22xCanadian Solar CS6P-225P. The company does claim to have a "plus only" 5% tolerance on the power rating. But I think that the unusually sunny winter weather has been the key factor responsible for my better-than-expected energy harvest. No way to know for sure without an irradiance meter.
  • solar_davesolar_dave Solar Expert Posts: 2,366 ✭✭✭✭
    Re: This is the winter of my contentment!
    jagec wrote: »
    Panels are polycrystalline, 22xCanadian Solar CS6P-225P. The company does claim to have a "plus only" 5% tolerance on the power rating. But I think that the unusually sunny winter weather has been the key factor responsible for my better-than-expected energy harvest. No way to know for sure without an irradiance meter.

    Yeah PVwatts takes your local weather into account, if it has been better than historical you will see lots more.
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