1)Grid-tie:
Most modern PV systems are grid-connected,meaning electrical energy is directed into the existing municipal power grid.
Energy is effectively stored in the grid.When a grid-tie system is generating more energy than you need:your electrical meter turns backwards.Many large arrays are intended solely for use as power plants,enhancig or supplanting the need for conventional power plants.Grid application systems do not need large batteries.

2）Off-Grid
Many PV systems are used to energize remote homes, facilities,and devices.
Energy is gathered from solar modules and is directed into energy storage devices for use when needed.These systems often supply the entire amount of energy required.