I recently had a 6.6 kW solar PV system with a 5 kW inverter.installed. Keen to see how it would reduce my off-the-grid kWh usage, I read the solar meter 10 days after installation, and it indicated 340 kWh. Excellent I thought, that's about 40 kWh more than I would have used otherwise. I then looked at the usage data on my AGL account for the same 10 day period, which showed I had bought 262 kWh from the grid and sold 132 kWh to the grid. My question is, where did the additional 208 lWh (340 minus 132) go that I would have to pay for?
That can be a bit confusing when solar is first installed, I am sorry that it is not clearer, allow me to explain.
When your solar panels are producing power, you use that power in your home and the excess is exported to the grid. Then at night when you are no longer generating the solar you buy it from the grid.
Specific to your question, the 208 kwh would have been consumed by the household during the day.
To get the most of your solar system you should use your appliances during the day as opposed to at night so you can use your solar power which is essentially free power.