Reverse electrodialysis: Fundamentals

Renewable energy can be captured when mixing two water volumes with different salt concentration in reverse electrodialysis (RED), using ion exchange membranes (IEMs). This chapter describes the historical development of RED, membrane transport phenomena, practical RED operation, benchmark parameters and R&D perspectives. Amongst others, the effects of feed water composition, membrane and stack design and flow direction on the obtainable power density and efficiency are discussed for practical RED devices. This chapter reviews current research and indicates the remaining challenges and R&D perspectives for producing electricity from salinity gradients with RED.