These trees are kicking my ass. We just suffered the worst June ever, following the worst May ever. Our solar electricity production is about a day above last year’s at this time (1644 kWh vs 1634 kWh through June 21) but significantly under the two prior years: 1986 kWh by late June, 2004, is our record.
I noticed during my last trip up to the roof that the tall sycamore across the driveway from the house is now putting 1/3 of our array into shadow at 4:30PM. Needless to say, this nukes our generation for the rest of the afternoon, including 90 critical minutes of the utility’s “peak period.”
The tree in question has also enveloped all the cables coming into the house — data, telephone, and electric — so it has needed attention anyway. (High winds plus tree limbs equal extended power outages.) I’ve scheduled our tree surgeon for a visit next week.
The other problem we’re having is dirty air. I have washed the panels more often this year than any other, every 3 weeks on average, and they seem dirtier than ever before. I scrubbed them clean 11 days ago, and yet when I stand with my eyes just above the plane of the surface of the panels, they look completely opaque with dust. I wonder if more people are burning trash now than in previous years?
There is some good news: our electricity charges for 2007, despite production woes, will be lower than the prior two years. Last year’s fee was ~$160.
I mention the financial aspect to make clear that despite maintenance issues, the PV system on my roof will save me about $1000 in electricity costs this year.
Update 2007-10-18: It wasn’t the trees after all.