Saltwater Power

An innovative conversion of seawater to power is illustrated by the so-called “salinity battery,” which is driven by the osmotic gradient created between seawater and freshwater stored on either side of a synthetic membrane. As fresh water moves spontaneously through the membrane to dilute the dissolved salts on the other side, the seawater is pressurized and then piped through a turbine to generate electricity. Challenges to salinity power include developing an optimal membrane and building a facility that can operate in deltas, estuaries, or other locations where rivers and oceans meet. Anticipated environmental impacts include the disposal of brackish water (although less salty than brines produced by conventional desalination plants) and the presence of platforms or pylons in potentially sensitive aquatic habitats. Nevertheless, this salinity-powered battery is based on emulating a natural process.