Hey hb1,
Thank you for your post!
The answer to your questions largely depends on whether you have 'Gross' or 'Net' metering. Gross metering solar systems have been set up to send all the solar power you generate to the grid, whereas Net metering solar systems are set up to send energy to your household first, before sending the excess energy back into the grid.
Unfortunately AGL have no way of knowing which of the two you have, however we do find that the majority of residences are now set up with 'Net' metering. If this is the case, then you'd be best served using appliances during the day so that you can make use the power that your panels are producing to run these, as opposed to buying power from the grid.
Kind regards,
Jayden