Note : Selling excess Electricity back to the Grid , depends on you Local Government’s Solar policy .
Grid Connected Solar Power (no Batteries)
Its the cheapest and most convenient systems to install. You are using the existing electrical grid as your ‘battery’. If you need power, you draw it off the grid as before. If you are producing more than using (like during the workday on a sunny day) you export the excess power back to the grid. Depending on your utility, you will get a credit back for your excess production.
Grid Connected Solar Power ( with Batteries )
These systems are connected to the grid just like the other ones, but also have batteries to provide storage to be used during an outage. When your batteries are fully charged, all excess power will be sent out to the grid as before. During an outage, the batteries will run your critical loads until either the power comes back on or the batteries run dry. Ensuring smooth power supply thought the day .