Method for desalinating saltwater using concentration difference energy

A method for desalinating saltwater, comprising:

• (a) generating a drive voltage using a plurality of drive cells in ionic communication with each other by:
• (i) flowing a diluent of a first ionic concentration through a diluent chamber of each of the drive cells;
• (ii) flowing a concentration of a second ionic concentration that is greater than the first ionic concentration through a concentrate chamber of each of the drive cells, the concentrate and diluent chambers of each of the drive cells sharing one of an anion and cation exchange membrane such that anions or cations flow from the concentrate chamber to the diluent chamber through the exchange membrane;
• (b) applying the drive voltage across a product chamber through which flows the saltwater to be desalinated and that is in ionic communication with the drive cells, the product chamber bounded by and in ionic communication with a product chamber anion exchange membrane on one side and bounded by and in ionic communication with a product chamber cation exchange membrane on another side, wherein the drive voltage equals or exceeds a desalination voltage of the product chamber such that cations and anions migrate from the saltwater through the product chamber cation and anion exchange membranes, respectively;
• and
• (c) reversing the polarity of the drive and sufficient voltages to descale the anion and cation exchange membranes;
• wherein saltwater exiting the product chamber has a lower ionic concentration than diluent exiting the diluent chamber.