Harvesting Salinity Gradient Energy by Diffusion of Ions, Liquid Water, and Water Vapor

In this paper, we briefly discuss the main points of salinity gradient energy (SGE). First, we discuss the sources of SGE and the methods to harvest it. Then, we calculate, using the laws of physical chemistry, the amount of energy that can be harvested with three selected methods based on the diffusion of ions, liquid water, and water vapor, respectively. Then, we give an overview of the applications, highlighting a number of new developments such as assisted reverse electrodialysis (ARED) and energy storage. It turns out that reverse electrodialysis offers unexpected possibilities such as energy storage, utilizing waste heat, and the administration of transdermal drug delivery, a technique that has been launched very recently.