Reverse electrodialysis (RED) generates electricity from the potential energy created by mixed water solutions producing a salinity gradient. This study presents a review of the most important parameters related to the RED process. Membranes are an essential component of an RED system. Hence, this review investigates different types of membranes, such as tailor-made and commercial ion-exchange membranes, nanoporous membranes, nanofluidic RED systems, pore-filling membranes, and profiled membranes. Additionally, other concepts of RED such as flow batteries based on the neutralization reaction of an acid and a base through a bipolar membrane and a heat engine are studied. Additionally, this work presents key electrochemical properties, operational parameters, and stack designs. A key drawback of all membrane processes is fouling. This work reviews the types of fouling faced by RED and the available antifouling strategies. The pilot scale and limitations of RED commercialization are discussed. A new RED hybrid process is proposed for potable water production, hydrogen generation, and desalination applications, which simultaneously produce energy.

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