I'm a builder who just had a PV system installed on a project. The inverter is saying 300 Kwh have been generated but the meter outside is saying only 200 have been fed back to the system. Why the difference? Is that normal? It's a sunnyboy inverter.

I would ask the installer but we may not be on the best of terms. The owner contracted this part of the job.

Typically, in a grid-tied system, only what is not used onsite gets put back into the system. Is the meter you are referring to the utility company service meter? Production meters show what was produced in total.

Yes, the power company meter. It has two numbers on it. One, I assume is the total usage, the other, I think, what was fed back to the grid.

So, presumably, 100 kWh have been consumed onsite. Is that possible?

Perhaps with the heat pump.