Osmotic power

Statkraft, the third largest producer of power in the Nordic region, is to build the world's first prototype osmotic power plant close to the paper pulp manufacturer Södra Cell Tofte’s facility at Hurum in Buskerud, Norway.

In an osmotic power plant, freshwater and presurised seawater are fed into a membrane module where 80 – 90 per cent of the fresh water is transferred by osmosis across the membrane into the seawater. The osmotic process then increases the volumetric flow of high pressure water.

The brackish water from the membrane is then split into two. About one third of the water goes to a turbine to generate power, while two-thirds return to the pressure exchanger to pressurise the feed of seawater.

The company claims that the global potential for osmotic power production is around 1600TWh, including around 200TWh in Europe and 12TWh in Norway, or 10 percent of Norway’s current power production.