Types of Rooftop Solar Power Plants

Grid-tie roof top solar This system is connected to the main supply grid. They supply power to the grid and also meet their load demand. These systems will not generate power during a power failure as the inverter shuts down the system to stop sending power into the grid and avoids the risk of electrocuting utility personnel who are working to repair the grid.
Grid-interactive roof top solar This system is a step above than grid-tie roof top solar as it has a backup unit to meet the load demand in case of a power failure. The backup system used is predominantly battery units or diesel generator in off-grid applications.
Off-grid solar In this category, the system is completely isolated from the grid which means that, whatever power that is generated from the solar panels is completely utilized to supply the load with the help of a battery bank.