Abstract
Salinity gradient energy （SGE） refers to the source of renewable energy generated by mixing two solutions with different salinities. Among several technologies for extracting SGE, reverse electrodialysis （RED） has attracted both research and industrial interest as a promising membrane-based technology to directly convert SGE to electricity. Since the concept of RED was first proposed in the 1950s, many researchers have worked on the development of RED-related technologies, and tremendous advancements have been achieved. However, although several pilot-scale experiments have been recently conducted and promising outcomes have been obtained, to the
authors’ knowledge, RED has not yet reached the commercialization stage. To fill the gap between the current technical level and the required level for commercialization, the objective of this review is to present the i） principle of RED, ii） process parameters/factors controlling the performance of RED, iii） current status of performance obtained from pilot-scale RED systems, and iv） main technical barriers that remain and inhibit the commercialization of RED. In addition, the combination of RED with other desalination processes to overcome the limitations of each individual process and/or to enhance the power generation capability of RED is briefly explained.
