Solar Panels!

I haven't posted here in a while.  Last you'd heard from me was a little over a year ago when I was getting ready to have my solar panels installed.  Well, they are on my roof and have been producing power for over a year!  Here's what they look like.

And here are the details.  There are ten panels which each can produce 240 watts of DC power on a clear day when the Sun is at zenith and the Sun's rays are normal (perpendicular) to the panels.  There are some losses when transmitting and converting the signal to analog, but this should still result in 2.07 kW (2070 Watts) of AC power at peak.  This is enough to run my microwave, TV, several light bulbs, and my dishwasher at the same time.  It's only about a quarter of the power used by my air conditioner.  The whole thing is connected to the grid.  If it's producing more power than my house uses, it puts the excess power onto the grid so my neighbors can use it (and causing my meter to run backwards).  When I'm using more power than my panels are producing (at night or when running my air conditioning), I take power off the grid.  The net amount that I produce/consume is monitored by a new "net meter."

So yes, it's still using the grid.  And even when I produce the same amount of power as I consume, I still have to pay for upkeep of that grid ($18/month in fees).

The whole thing is hooked up to a monitor which determines the power output of each panel every five minutes and uploads it to the web.  Here is the data from two days last August.

The first day was partly cloudy and the second day was clear.  You'll notice that the peak power does not reach 2.07 kW.  That is due to a number of things.  The Sun isn't at zenith, its rays aren't quite perpendicular to the panels, but most importantly, some of the light is being absorbed by smog and water in the atmosphere.  I can see a big 10-15% boost in power when we have strong Santa Ana winds which blows away all moisture and smog.

One really interesting fact about the solar panels.  The total area of the install is 175 sq. ft, or about 9% of the total roof area!  And it will supply all of the energy I ever need.  My installation is about half of the size of other similarly sized homes with solar power in the area (because my house is very efficient).  But still, the point is that even in a way less efficient house, in the American southwest, it is easy to produce power for your house with ~20% of the area of the roof or less.  Of course, in cloudier areas, you will need more.

Now go read about how the panels did after one year in my next post!