Reverse Osmosis system electricity consumption
Electricity consumption depends on raw water quality (individual ions concentration), Reverse osmosis system design (system recovery rate, number of stages, type of membranes, etc.) and operating conditions (water temperature).
You can use Reverse osmosis design simulator to estimate electricity consumption. It is not an accurate result but will give you a very good idea, and making some tries in different conditions will precise the results. No electricity consumption result from another system will be exactly the same as yours. The reasons are that: they don’t have same water quality, same pumping equipments and same type of Reverse Osmosis system (in term of design) as yours.
I use ROSA, a Dow-Filmtec membrane systems simulator. It is a free software that you can download on their website (http://www.dow.com/en-us/water-and-process-solutions/resources/design-software/rosa-software) and install on your computer. Simulation will give you a bunch of information including electricity consumption.
Try it. If you need help, let me know.