Salinity gradient energy, which is also known as Blue energy, is a renewable energy form that can be extracted from the mixing of two solutions with diﬀerent salinities. About 80% of the current global electricity demand could potentially be covered by this energy source. Among several energy extraction technologies, reverse electrodialysis (RED), using anion and cation exchange membranes for ionic transport that is converted into an electrical current at the electrodes, is most promising. This study provides a brief overview of recent advances in RED technology. Furthermore, it discusses future research directions and prospects to expand the true potential of this technology for power generation. Major emphasis should be on the development of task-specifc membranes and stacks, the control of fouling and the design of new applications and hybrid processes.