The most common type of solar energy system, a grid tied system produces the fastest return on investment. The system connects to your local electric utility grid through the service panel in your home or business. This method of connection is popular because it offers the dual advantages of providing free solar energy while enabling you to maintain the same consistency in power you now receive from your local utility.
The power produced by a grid-tied solar energy system fluctuates depending on the weather. If the power is depleted at night or in cloudy conditions, you’ll receive traditional electricity through your local power company. Conversely, when the sun is at its brightest, the solar power could feed all of your circuits with some still left over. With a grid-tied system, the excess energy is returned to the grid and you get a “credit” for that electricity. This surplus power will go out of your house through your meter, actually making your meter spin backwards.
If there is a blackout, the PV system shuts down and no solar power will be produced until your local power company restores power to the grid. This is required to prevent the flow of power that could endanger utility workers. When the blackout ends and power is available from the grid, your solar system will sense this and start working again.