How Solar Bill Credits Offset Night-Time Use
Surplus power your panels export is taken off this month's bill, and whatever the bill doesn't absorb is carried as a credit toward a later one.
That is what lets a grid-tied home lean on the grid after dark: the credits earned at midday pay for the power drawn at night. The terms vary by utility, and FPL Net Metering sets out how the credit is applied to the monthly bill.
Midday
The panels make more than the house is using.
Export
The surplus flows out through the meter to the grid.
Your bill
It comes off this bill, or waits as a credit for the next.