Statkraft, a state-owned power group of Norway, is running the osmotic power plant prototype in a former chlorine factory on the banks of the Oslo fjord, about 60 kilometers south of Oslo.

Osmotic energy is based on the natural phenomenon of osmosis. When freshwater and seawater meet on either side of a membrane — a thin layer that retains salt but lets water pass — freshwater is drawn towards the seawater side.

Researchers found in the phenomenon of osmosis, there is pressure on the seawater side. And this pressure can be used to drive a turbine to produce electricity.

Osmosis has been used by industry to desalinate seawater, but Statskraft’s power plant at Tofte is the first time it has been used to produce energy.

“While salt might not save the world alone, we believe osmotic power will be an important part of the global energy portfolio,” said Baard Mikkelsen, the head of Statkraft.

Unlike other energy sources such as wind and solar power, osmotic power produces a stable electricity flow regardless of weather conditions, and could be installed almost anywhere where rivers flow into the ocean.

The worldwide potential of osmotic energy is estimated at 1,700 terrawatt hours per year, equivalent to half of the European Union’s energy production.

Statkraft said it hopes to build the first commercial osmotic power plant in 2015. The new plant will have a 25 megawatt capacity, enough to provide about 10,000 households with electricity. 

On Xinhua Web site: http://news.xinhuanet.com/english/2009-11/25/content_12537054.htm