This article is the result of work carried out by Salzgitter Anlagenbau GmbH with the ultimate objective of defining the most suitable technique from an energy point of view for reliably producing desalinated water of the required specification with the lowest possible prime energy consumption. It describes how Salzgitter Anlagenbau GmbH has approached and achieved this objective. Furthermore, a new concept for a power/RO cogeneration design is introduced. The merits of various desalting technologies is not covered.