Grid connected solar PV systems are by far the most common and widely used by homes and businesses. These systems do not need batteries and use a solar inverter to convert the DC energy from the PV panels to produce AC energy that you can use to power your home.
Any excess solar energy that you generate is exported to the electricity grid and you may be paid a feed-in-tariff or credit for the energy you export.
Grid connected solar PV systems are not able to function or generate electricity during a blackout due to safety reasons. The solar inverter will shut down to prevent electricity feeding into the grid to protect the safety of the people repairing the faults in the network.
AC coupled batteries are able to be added to on-grid systems at a later stage if required such as the Tesla Powerwall.
Modern hybrid solar PV systems combine solar and battery storage in one and are now available in many different forms and configurations. Due to the decreasing cost of battery storage, systems that are already connected to the electricity grid can start taking advantage of battery storage as well. This means being able to store solar energy that is generated during the day and using it day or night. When the stored energy is depleted, the grid is there as a back up, allowing consumers to have the best of both worlds.
Hybrid solar PV systems are also able to charge the batteries using cheap off-peak electricity.
Also hybrid solar PV systems with battery storage are able to automatically isolate from the grid and continue to supply some power during a blackout if they are configured to backup mode.
(c)Aztek Wind and Solar 2022