I am not a solar PV system expert at all. I have very limited knowledge in the area. But I am concerned that people are being scammed by installers of roof mounted residential solar power systems. Please correct me if I am wrong.
I say this because people are paying many thousands of dollars for systems that can't possibly produce that much power. Even if somebody else is subsidizing the system like the Gov't or the utility, they don't make economic sense for the individual and even less sense for the taxpayer or ratepayer.
It's my understanding that solar panels produce the most power when they are directly facing the sun (exactly 90 degrees). The amount of power produced falls off greatly as the angle changes from 90. The best systems track the sun keeping the panels in proper alignment as much as possible. Cheaper ground based systems don't move, but are at least aimed to maximize the potential sun input. Then there are residential systems that are built on people's roofs (usually flat to the roof). The roof could be way out of alignment with the sun and a solar contractor will put panels there anyway.
It's also my understanding that if any portion of any panel in a string of panels becomes shaded, this significantly reduces the output of the entire string, yet I see panels installed near chimneys, antennas, trees, and other things that throw shade at some point during the day.
In my travels I have seen many PV systems installed at my clients homes. The vast majority of them are backfed to the panel on a 2 pole 30 amp breaker. This must mean that the PV system produces less than 30 amp at its peak. Since the peak is only a few minutes each day, I suspect that most of the rest of time it's producing far less: 15 amps?, 10 amps?, 5 amps? And of course, the system produces zero amps at night.
A thirty amp breaker is probably what the system manufacturer requires, but since most systems are not installed to maximize solar input as I mentioned above, they are probably producing far less.
Is 15 amps of solar power for a couple of hours each day worth $10-20K in expense? And what if the roof needs replacing and all the panels have to be removed and reinstalled? And what if an inverter craps out and you have to replace it? I hear many clients talking like they are going to power their entire house off the system and sell gobs of power back to POCO. Then they wonder why it's not working. Were they oversold?
If homeowners want to create an aura of "greenness" around themselves, then fine. Otherwise, in my humble opinion, it doesn't make sense. I'll stick to recycling and bringing my own bags to the grocery store.
