My Home’s Solar Performance Year 1

I installed 39 solar panels on the roof of my home one year ago. How did the system perform?

The installation is 7.995 KW in peak DC capacity. The AC capacity is 7.4 KW. The panels are from Day4 based in Vancouver, with Enphase micro inverters. The installation was purchased from my nephew’s company, Estill Energy. The purchase price including HST was $67,000.

The forecast production was 8423 KWh per year. The estimated production was prepared by Estill Energy, using a laser system to assess shading issues, and software to estimate the output based on the angle of the roof, and the orientation of the roof surface. The house is oriented to 240 degrees or basically WSW, and of course 180 degrees would be perfect. The roof slope is 15 degrees – 35 or 40 would be better. There is some shading of the roof from trees, mostly in the winter when the sun is low in the sky. The estimated production for the roof if there was no shading was 8855 KWh.

The forecast provided had estimated output monthly. I told my nephew that his software probably didn’t account properly for snow loads in the snow belt where I live – I am not about to go on the roof to shovel panels, and risk damaging them, for a few dollars. And we get a lot of snow, and it is very cloudy from November – February while the Great Lakes are still warm. I was right – there was very little production in December, January, and most of February. But then again, the forecast didn’t anticipate much winter production as this is when the shading is the worst, and of course the days are short.

Actual production as measured by the inverters, for December 1-November 30 came in at 8760 KWh, or 4% more than forecast. Not bad considering the impact of snow on production. This resulted in revenues of $7025.00 and gives about a 9.5 year payback. I calculated the return on capital at 9.3%.

One of the bigger events of the year was that a tree fell on the house. It was an aspen tree, about 10 inches in diameter at the base. Fortunately, the branches of the tree spread the weight of the fall and remarkably, there was no damage to the panels or the roof. I was away when this occurred, so there was certainly some production lost while the tree branches and leaves were on the roof. But all of the panels still work well – indeed, they saved the shingles from damage.

So I am one happy customer. The bottom line is that this installation performed as advertised. Solar works.

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