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Norway unveils osmostic power plant, using salt to make electricity

Wed Nov 25 02:48:24 EST 2009
Tue Nov 24 15:48:24 UTC 2009

TOFTE, Norway, Nov 24 AFP - Norway unveiled the world's first osmotic power plant on Tuesday, harnessing the energy-unleashing encounter of freshwater and seawater to make clean electricity.

"While salt might not save the world alone, we believe osmotic power will be an important part of the global energy portfolio," the chief on state-owned Statkraft, Baard Mikkelsen, told reporters.

Statkraft, which presents itself as the biggest renewable energy company in Europe, is running the osmotic power plant prototype on the banks of the Oslo fjord, about 60km south of the Norwegian capital.

Osmotic energy is based on the widespread natural phenomenon of osmosis, which allows trees to drink through their leaves and plays on the different concentration levels of liquids.

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. The flow puts pressure on the seawater side, and that pressure can be used to drive a turbine, producing electricity.

The point of osmotic power is "to use power not against nature but with nature", summed up Sverre Gotaas, in charge of innovation and growth at Statkraft.

Osmosis has been used by industry to desalinate seawater, but the company's prototype at Tofte marks the first time it has been used to produce energy.

Although the plant will for now produce just enough electricity to power a coffee-maker, it could prove to be a great potential clean, environmentally friendly power source.

"It has very, very limited environmental consequences. It's only positive and it can be used in many places," Frederic Hauge of environmental organisation Bellona told AFP, adding the development of osmotic power was "very exciting".

Because they produce energy from the encounter of freshwater and seawater, osmotic power plants could be installed almost anywhere where rivers flow into the ocean.

"Even countries that do not have oil, coal or mountains will be able to produce their own energy," Rasmus Hansson, the head of the World Wildlife Fund in Norway told AFP.

"It is very nice when industry imitates nature," he added, lauding Statkraft's decision to invest around 150 million kroner E17.9 million ($A28.98 million), in a "revolutionary technology".

Statkraft hopes to start building the first commercial osmotic power plant, which would have a 25 megawatt capacity, enough to provide about 10,000 households with electricity, in 2015.