Grid Connected systems' main characteristic is that they are connected exclusively to the grid. These systems often are called On-Grid.

The main idea of having On-Grid system is to supply your electricity authority with electricity you produce in your premises for a fee.

However the main inconvenience of such system is that practically you cannot use it yourself. In no case you will be able to use the electricity you produce. Even if electricity cut out occurs, be it scheduled maintenance or a total blackout, the system will shut itself down and will no longer be generating electricity.