Norway uses osmosis to generate power

TOFTE, Norway, Nov. 24 (UPI) -- Norway on Tuesday unveiled the world's first osmotic power plant, which uses a combination of seawater and freshwater to make clean electricity.

In the presence of Norway's Crown Princess Mette-Marit, officials from Norwegian renewable energy company Statkraft at Tofte, some 30 miles outside of Oslo, unveiled an exciting new power plant concept. The Tofte facility for the first time uses osmosis -- the natural phenomenon enabling plants to take in water through their leaves -- to harness the energy unleashed when saltwater and freshwater meet.

The plant channels freshwater and saltwater into chambers separated by an artificial membrane. The freshwater flows through the membrane to equal out for the difference in salinity. This increases the pressure on the seawater side to an equivalent of a 350-foot water column -- quite a significant waterfall that can be used to run a turbine that generates electricity.

"This is something Statkraft can be proud of and something I … am proud of too," said Norway's Oil and Energy Minister Terje Riis-Johansen. "We are at the forefront and we're opening something which has never been opened before!"

The plant at Tofte has an initial capacity of only 2-4 kW -- just enough to run a coffeemaker that on Tuesday supplied a cup of tea for the crown princess. Yet the potential of the green energy source is huge.

Statkraft, which together with a few other companies invests around $27 million in the technology, says osmotic power plants could generate up to 1,700 terawatt hours of electricity per year -- that's half the total annual electricity production in the EU. Besides Scandinavian nations, countries with good osmotic potential include Russia and Canada. Comparable resources also exist in South America and Africa.

But to make osmotic power plants viable, their efficiency has to be improved.

Statkraft's test plant has an efficiency of less than 1 watt per square meter; the company aims for a 5 watt efficiency that could make osmotic energy cost-effective.

The Tofte plant will be in operation for up to three years, before Statkraft will construct a 1-2 MW pilot facility, the company said. It wants to build a full-scale osmotic power plant in 2015.

Osmotic energy was pioneered by American scientist Sidney Loeb, who in the early 1970s indicated that membranes used for desalination could be used to generate electricity.