Seawater desalination with reverse osmosis has taken a noteworthy upturn in recent years. One of the reasons for the success of the membrane process is its lower energy consumption in comparison to the thermal desalination processes. Due to advances in the efficiency of energy recovery systems of the seawater desalination stage (1st Pass) of SWRO - plants in the last decade this advantage of membrane processes has even increased. Now, however, the energy consumption of an SWRO is also influenced by a huge number of additional factors. These are of an external nature as well as determined by design and configuration of the plant. Environmental conditions and - stipulations dependent on the location of the plant and furthermore the influence of operating modes are additional factors. The individual systems of an SWRO plant - in particular its pre-treatment stage as well as its first and second passes are very closely cross-linked systems in regard to its energy consumption. During energy optimisation in des...