The subject of energy recovery for seawater membrane desalination has been in a constant state of flux for all of the years since the inception of the concept of using reverse osmosis for desalination. Due to the high costs associated with the operation of these facilities, a way to recoup some of those costs to improve the operational economics has been a high priority. In this paper we discuss the historical changes associated with the variety of energy conservation technologies as well as the operational differences between them. We also look into the relative efficiencies of the technologies available and the design considerations of using these devices. Much of the focus of this dissertation will be the recent changes in technology which have drastically lowered the operational energy requirements for the high-pressure reverse osmosis process. These newest developments will help to bring the widespread use of membrane desalination to the forefront of potable water production in the new millennium.