Researchers at Penn State University used a hybrid technology to produce electrical power at the transition zone from seawater to freshwater on coasts. It relies on the difference in saline concentration between the two water mediums to generate power. The team estimates the locked energy potential in such a medium is enough to meet 40% of the world’s electricity demand.
Making electricity from varying saline concentrations in water or a saline gradient isn’t exactly a new idea. In 1973, Prof. Sidney Loeb from Ben-Gurion University of the Negev, Israel, invented such a power generation method called pressure retarded osmosis (PRO). This technique selectively allows water to pass through a semi-permeable membrane littered with tiny holes but blocks salt. The resulting osmotic pressure is what generates power by driving a turbine.