How Solar Works

Photovoltaic panels utilize solar radiation (sunlight) to produce Direct Current (DC) voltage. An inverter then converts DC voltage into Alternating Current, or AC voltage. AC is standard household electricity.

On Grid or Off-Grid?

If your solar electric system is on-grid, the AC power travels to the electrical panel and is now ready to service the electrical needs of your home or business. Typically, your solar electric system will produce power during hours of direct sunlight (6.4 hours on average in Arizona) and use power from your local electric utility during the evening. The utility company monitors the electricity supplied by your solar electric system; in some instances, your meter will actually turn backwards as you accumulate credits with the utility company. These credits then can be applied during times when your solar electric system produces less or when electrical consumption is greater. This arrangement is called net metering or net billing. An on-grid system is by far the most maintenance-free to operate.

          

On-grid systems are required to shut down when there is a power outage to protect utility workers. When there is a blackout, your solar electric system will not operate. For critical electrical needs (well pumps, computing systems, or medical equipment, for example), a battery bank can be installed as a backup to your grid-tied system. Incorporating batteries into the system requires more components, costs more, and lowers the system's overall efficiency. But for homeowners who experience frequent power outages or have critical electrical loads, a backup energy source is essential. Batteries will need to be replaced every 7-10 years.

          

Off-Grid

The photovoltaic technology used to to produce electricity is the same in an off-grid system. The critical difference is that off-grid systems are not connected to an electric utility. They work independently from the grid to provide all of a household's electricity. That means no electric bills and no blackouts - at least those caused by grid failures. Off-grid systems most often are installed in remote locations without utility grid service. People also choose off-grid systems for a more independent lifestyle or the general reliability provided by a solar electric system. These systems require more maintenance than on-grid systems, and the utility rebates are slightly less than on-grid system rebates.