How to modeling and simulate an energy meter ?

My final dissertation concerns the evaluation of the amount of electrical energy from the public grid that can be coupled to a photovoltaic installation. The main objective is to estimate the quantity of photovoltaic energy that can be injected into the public grid.

I have already modelled and simulated the PV system connected to the grid but to achieve the goal, I need two energy meters (consumption and production). But I can't model one meter. That's why I need your help to model and simulate the two energy meters (consumption and production). Thank you in advance.