hat is the advantage of having Batteries?

With a Hybrid / Bi-directional system, the batteries can either be used to supply power when the Solar PV is not supplying power / not supplying enough power i.e. at night. During power outage (Loadshedding), the batteries will power critical components like alarms and electric fences to ensure Safety & Security, as well as entertainment equipment like TV, DSTV, etc. and essentials like Fridges / Freezers. A Grid Interactive solution will reduce risk.

Grid Tied systems requires either Grid or Generator power to supply Solar PV power. Grid Tied solutions can therefor be integrated to run with Generators.