Japan has opened its first osmotic power plant – so what is it and how does it work?

Japan’s first osmotic power plant uses the process of osmosis to power a turbine that in turn creates energy. Photograph: Fukuoka Area Waterworks Agency

Japan has opened its first osmotic power plant, in the south-western city of Fukuoka.

Only the second power plant of its type in the world, it is expected to generate about 880,000 kilowatt hours of electricity each year – enough to help power a desalination plant that supplies fresh water to the city and neighbouring areas.