Not only poles and wires charges in your tariff, but daily supply charge of course . . . I believe some charge poles and wires in the tariff, while others put some or all of that into supply charge.
So you put X kwh solar into the grid, used Y kwh from the grid . . . there can be significant differences in the FIT and usage charge, and at various times of day if on a TOU plan tariff, Plus TOU times can vary dramatically between states and regions within states where applicable.
For example here in SA, we have only one DNSP, and the TOU tariffs for peak are 13 hours a day.
Between 0600 and 1000, and between 1500 and midnight, covering ALL the busy times of early morning and the whole mid afternoon through all the evening to midnight.
So the Peak TOU tariff here is 53c/kwh.
The FIT paid in SA is 2c.
So if you solar contribution is to counter just your peak usage, you need to be putting in more than 26x the solar to the grid than you are using by that peak usage . . . next cheapest is Shoulder between 1000 and 1500, that's ~ 27c.
All DNSPs have discrepancies in usage vs FIT, some are only 2.5x, up to what I think is the worse case here in SA as above.
