You might be better off selecting a different energz meter (and possibly flow meter). For energy meters you can find Siemens, Schneider, Lenze, whatever, which lareadz have a Modbus TCP (ethernet based) interface. It will be much easier to integrate, you do not need a HW gateway, you can plug it in to any ethernet network. If you want to use Node-Red you can read modbus TCP via NodeRed. Otherwie it is hard to evaluate the solution if there is not context to it. What is the goal of this all?