This week I'll go over the basics of a solar electric system and then I'll cover what this means to you and for your utility bill. 

Sunlight hits your home almost everyday here in San Diego County.  This is energy that is already hitting your house and normally just goes to waste.  A solar electric system captures some of this light energy and puts it to good use. 

Photovoltaic Solar Cells generate electricity by converting the sun's energy to electricity. Solar cells are "semiconductors" (a material with unusual electrical properties) that capture the sun's light and convert it to electrons(electricity is just a flow of electrons). 

Solar panels are groups of solar cells that are enclosed in a frame to protect them from rain, snow, ice, etc and most things that may hit them on your roof.  Solar panels collect and convert the sun's energy to DC electricity (green line below). 

This electricity is then changed (by an Inverter) to the same Type of Electricity (AC, blue line below) that your utility company provides to your home. 

The lights and appliances in your home can then use this electricity and any "extra" unused electricity is sold back to the utility company using Net Metering.  Net Metering just means that you pay for any electricity you use minus any electricity your system makes.  

During the day when there is full sunlight your solar panels are producing quite a bit of electricity.  If you are home you can use this electricity, but if you're at work then the unused electricity is "sold" to the utility company at full retail price.  Or if you are at home and your solar electric system is producing more electricity than you are using the excess is sold to the utility company also. Your meter will actually run backwards when you are generating more electricity than you are using (you can show this off to your neighbors)

At night when there is no sunlight and so your solar system is producing no electricity.  But you are connected to the utility grid and so buy electricity from the utility company. 

You simply pay for the difference in electricity that you use minus what your solar system produces.  Or the "net" amount which is where the term net metering comes from. 

Robert Morse
BSEE, MSEE
SunCal Solar, Incorporated
www.SunCalSolar.com