Hi Ghada,
please see the explanation about simulation I just wrote in another thread:
In a productive system you do usually have at least a physical Grid-Meter at the grid connection point. We often use SOCOMEC or Janitza meters via Modbus/RTU or Modbus/TCP for that purpose. Additionally it’s recommended to measure also the production either via a separate Production meter or by direct communication with a PV inverter (e.g. Fronius, KACO, Kostal, SMA, via SolarLog, or generic SunSpec compatible.
The Consumption can usually not be measured and is calculated from Grid, Production and Energy Storage power.
Regards,
Stefan