This was written in March 2013 when the installation was completed.
Today was an auspicious day. A truck labeled “Real Goods Solar, Inc.” pulled up in front of our house at 8:00 AM, and a trio of young guys got out and started unloading tools and equipment. Ladders went up, and soon the sounds of cordless drills and hammers filled the house, scaring the bejeezus out of the cat who thought the world was coming to an end. I took him on my lap and assured him that we had safely passed the scheduled day for that event last year on December 21st, 2012. He was soon placated with a saucer of milk.
I spent most of the day pestering the crew, who turned out to be intelligent, witty and very tolerant of my questioning and incessant picture-taking. When anything interesting is going on, I always have a camera in my hand. Some people are uncomfortable with that, but these guys didn’t seem to care. They went about their job efficiently and competently. First they laid out the area on the roof where the panel would be placed, and started drilling holes for the anchor points for the support posts…much to the cat’s displeasure.
Next, the rails that would support the panels were mounted.
Then the microinverters, one for each of the twelve solar modules were attached to the rails and wired together.
Microinverters are a relatively recent innovation in solar array installations. Older systems used one large inverter. If part of the array was shaded, the output of the entire array went to zero. With microinverters, only the output from the shaded parts is lost. Also, an inverter failure takes out only one module, leaving the rest of the array working. Finally, microinverters implement a modular design that is easily expanded. The last point is especially important to me, because I plan further “electrification” of our house in the future.
Then, the solar modules were mounted on the rails and connected to the microinverters.
That completed the physical installation. Meanwhile one of the guys had been working at the other end of the house at the power panel, installing the safety switch and monitoring system.
Wires carrying the power from the panel were run through the attic from the solar array to the monitor, through the safety switch, and into the main power panel where it was connected to the power grid. Immediately upon completion, the monitor showed, even in the cloudy conditions this morning, that the array was making more electricity than we were using!
Here’s what the completed installation looks like. The original meter and circuit breaker panel are on the left. The two two dark gray boxes on the right contain the disconnect switch and monitoring system.
The monitoring system is connected to my computer and to the Internet, so I can check on the output of the panel at any time. Data is collected on a web site provided by the microinverter supplier, enabling me to see weekly, monthly and yearly totals, etc.
Now, the juice for my electric car will be coming directly from the sun. What a nice thought!
Here’s a final view of the completed system from the street. As you can see, it is barely visible. The trees in the background are on the north side of the house so they do not shade it at all.