In June 2001 we installed a photovoltaic solar system on our house. The system is modular and comes in 1 kilowatt units. Each unit consists of four 4'x8' solar panels and an inverter box. We got two of these units so we have 8 panels on our roof and two inverters connected to our main power panel. This page provides some very basic information and some pictures of our Photovoltaic Solar Energy System.
Q: How much power do you get from them?
A: The rule of thumb we've been told is to expect 5 peak sunshine hours a day. With a 2KW system, that's 10KW hours per day or approximately 300KW hours per month. Check your electric bill to see what percentage of your monthly total that is. For us it's over half and we have a lot of electronics in the house.
Q: Do you have batteries?
A: No. We could have them but they are an extra expense and not really necessary with a grid-tied system. A grid-tied system is one that is connected to the main power grid as opposed to being completely self sufficient. In a sense, the power grid is our battery. When we are producing more than we are consuming, we put power onto the grid. When we are consuming more than we are producing (e.g. at night) we are pulling energy back out of the grid.
Q: Does your electric meter spin backwards?
A: Yes! It was very exciting to see it start spinning backwards when the system was first connected. We both wanted to rush out and get more panels to see it go faster.
Q: How bad does it look?
A: I was pretty worried about the appearance because the best sun exposure is on the front of our house. Overall I don't think they are hideous. A magnolia tree in the front yard blocks much of the street view. Our neighbor directly across the street doesn't mind them at all. Check the pictures to see for yourself.
Q: How much did it cost and how long will it take to recoup the investment?
A: When we bought our system (June 2001) each unit cost $7500. Right after we bought them the price went up to $8000/unit. Fortunately, the state of California has a rebate of $4.50/watt or $4500/kilowatt. That brought our price down from $7500/unit to $3000/unit. So for 2 units we paid about $7,200 including tax. Installation was an additional $2,200 for a total of $9,400. Payback will be between 8-10 years depending on electric rates. The system itself is rated to last about 25 years.
Q: So you can have power during a daytime power outage right?
A: No. There are two reasons for this. First, PG&E (our utility) does not allow it. They don't want people putting power on the grid when they believe the grid is dead. Second, the inverters actually synchronize to the waveform from the grid. No waveform, no output from the inverters. You could do this with a battery-backed system, but we didn't go down that path.
Q: Who makes the system? Where did you buy them?
A: The panels themselves are from Siemens and the inverters are from Advanced Energy Systems. We bough them from Palo Alto Hardware (I don't think they have a web site). They can be reached at (650) 327-7222.
Here are a few pictures of our solar energy system. Click on each picture to see a larger view. There's really not that much to it. Just a bunch of panels and a couple of inverters.