Happy New Year everyone! Well, now that the new year is upon us and I finally have a full month of data collection, I can look at how well my solar installation has performed compared to what was expected. Be mindful that this really only 1 month of data. The true test will be once we get a full year of data. But I'm gonna show y'all anyway.
First let's get some of the background, shall we? Below is a pic of what PV Watts estimated my house should get. This is the same information that my Solar Contractor, Greenspring Energy, gave to me.
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PV Watts Information
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The PVWatts information has a big ole' asterisk with it though. This assumes full, unimpeded access to the sunlight. Well, my house isn't in the middle of a field, so these numbers are not realistic. That's where the SunEye report comes in as shown in the pictures below.
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| Monthly SolarEye Information |
As you'll notice, due to shading, I should expect at most, 75% of the unimpeded values with February- October getting the best results (72-83%) and November-January getting significantly lower (47-66%). December is the worst month with only 47%.
Wait...never seen one of these things? Well, essentially what they do is take this fisheye camera thingy (yes, "thingy" is a technical term) and put it on multiple points on your roof where it takes a picture and overlays how the sun will track across it. See the picture below:
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| SunEye Report for One of my Locations. |
In my case they took 3 pictures at the 3 points of the triangle of my southern facing roof. In the picture above (the peak of the triangle, best location) you can see how the tops of the trees (green) partially inhibit the sunshine from reaching my solar panels. The evening trees (picture right) are in my backyard and is about a 50/50 mix of trees in my yard and my neighbors yard. So if I wanted to increase my energy generation, I'd need to get myself a chainsaw. However, I don't want to do that because those same trees shade my house and keep the temperature down. I'll take that benefit instead. If there was one thing I'd do would be to trim some of the those top trees that are significantly reducing Nov/Dec/Jan. That could be really only 3-4 branches. In one instance I know there's a tree that's dead on the top (shown in the pic above, the green splotch where the 10am line and Nov line meet) that probably needs to be trimmed or come down soon anyway.
OK...enough of that tangent...so getting back to the discussion, now let's look at my generation (from the Tigo website):
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| Tigo Energy Recordings |
Overall I've produced just shy of 100 kWh/month for November and December. And don't forget that I'm missing about 6-10 days of data as the system was energized on November 7th and wasn't fully operational until November 11th. So let's take this data and compare it what was expected:
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| Comparison of Expected vs Actual Solar Power Generation |
As we see for December, I was just over what was expected for the month which is good! If we were to extrapolate November we'd be a little under (say 130 kWh vs 145 kWh), but it's at least in the neighborhood. I'd say "so far so good". I think what's going to be most interesting is when we get into this Spring.
I'll try to remember to post this similar information for each month in addition to my Duke Energy information. If I can, I'll try to combine the two when I can.
Any thoughts out there?
