Waste water to clean energy: Engineers in the city of Fukuoka opened world’s second osmotic power plant

FUKUOKA: A Japanese water plant is harnessing the natural process of osmosis to generate renewable energy that could one day become a common power source. The possibility of generating power from osmosis when water molecules pass from a less salty solution to a more salty one has long been known.

Engineers in the city of Fukuoka and their private partners think they might have cracked it, and have opened what is only the world’s second osmotic power plant. It generates power from the transfer of molecules between treated sewage water and concentrated seawater, a waste product from a desalination plant in the city.

Osmosis is the process that for example causes water to seep out of a cucumber or eggplant when sprinkled with salt. Water molecules move across membranes from an area of low solution concentration to an area of higher concentrated solution. At scale, that movement can be significant enough to turn a turbine and thereby generate electricity.