There are three different types of solar PV systems.
Grid-Connected: On-grid or grid-tie solar systems are by far the most common and widely used by homes and businesses. An on-grid system will use the energy produced from the solar panels during the day and will switch to the grid electricity during the night. These systems do not need batteries and use solar inverters and are connected to the utility grid. Any excess solar power that you generate is exported to the Utility grid per the National Electric Power Regulatory Authority (Alternative & Renewable Energy) Distributed Generation and Net Metering Regulations, 2015.
Off-Grid: An off-grid solar system means that you are not connected in any way to the grid. To achieve this, however, there is a need to purchase backup battery systems, which can be expensive, bulky, and are not very environment friendly. The battery systems will be charged during the day from the energy produced by the panels and will be used during nighttime.
Hybrid solar system: A hybrid solar system refers to a combination of solar and energy storage while also being connected to the grid.