Assuming a steady consumption over 24 hours a day is unrealistic. If that was the case then a 17 kW generator would do the job. In reality, there are times of peak demand, and your calculations should based on that.
It depends on your peak load. If the load is constant a 20 KW generator would do it. But if the load varies, you would have to size it for the peak load.
No way of knowing without peak load data.
I would assume that a 12500KWh/ month generator should do it?
