A Hybrid Solar System (Grid-Tie with Power Backup) is basically a grid connected solar system with batteries combine with an off-grid system. The electronics continuously monitor the batteries, the solar panels and the grid and decided:
• When to charge/Discharge the batteries.
• When to connect/disconnect from the grid.
This may sound very similar in cost and complexity to an Off-grid system. But the crucial point to understand is that, because your system is not totally disconnected from the grid, you save a lot of money on system Components. The grid is always thee if you need an electricity top up. This means that your system needs fewer batteries and depending on Grid failures no need for a backup power source (i.e. expensive diesel genset or any other source).