The world’s first power plant based on osmotic power — a small prototype plant — recently opened in Norway. The plant generates electricity through osmotic pressure: when salt water and fresh water come together, like when a river meets the sea, there’s a difference in water potential. The fresh water and salt water are brought into distinct chambers, separated by a membrane that lets only water molecules through. The salt in the sea water draws fresh water through the membrane, building a pressure (corresponding to a water column of 120 m), which can then be harnessed to generate energy. The challenge in making this cost-effective lies in making the membrane efficient enough. Once it is, we’ll have a new, sustainable energy source — the only waste product is salt water. The total potential is estimated to be around 10 percent of the world’s current electricity consumption. More (pdf).
