We are now really into the heat of things. May is the third most important month for solar radiation. So it is very important to maximize the power one generates in May. Only July and June are more important.
May 2012 was good month. Lots of sunny days. Plenty of mixed sun and cloud days. Just a few rainy days. Pretty much what one would expect. So now that the Deger tracking device has been fixed, we should have been generating power almost at the top of our potential.
At the end of April, I reported that our meter read 5720 kilowatt hours. Last night, once the sun went down, it read 7693. So we generated 1973 kilowatt hours. That is still short of the 2151 projected by PVwatts. It is 91.7 percent – much better than any other month, so far, but still shy of what we would have hoped.
Why?
PVwatts measures solar radiation in Ottawa, the closest big city. But Ottawa is still an hour’s drive away. Is it possible that there is a significant variation in solar radiation between here and Ottawa?
I have searched in vain for a regional radiation map. Anything I can find is Canada-wide, like the one below. If anyone knows where I can find more localized solar radiation data, I would love to hear from you.
In any case, the payment for May will still be by far the largest one yet, and the system is still a positive investment. So I am smiling even as I scratch my head.
