 Desalinated sea water is becoming increasingly important as global demand for freshwater increases. To meet this demand, various desalination technologies have been developed and implemented. Second law efficiency analysis can help to identify the most efficient desalination technologies by evaluating the amount of energy needed to produce a certain quantity of water. This analysis takes into account entropy generation caused by the process itself, as well as entropy generated during the rundown phase of the process. By considering both sources of entropy, it becomes possible to identify the most efficient desalination technologies. This article was authored by John H. Leanhardt v. Syed M. Zubair, Edward K. Summers, and others.