Nanotubes boost potential of salinity power as a renewable energy source
In November 2009, Norwegian state owned electricity company Statkraft opened the world’s first osmotic power plant prototype, which generates electricity from the difference in the salt concentration between river water and sea water. While osmotic power is a clean, renewable energy source, its commercial use has been limited due to the low generating capacities offered by current technology – the Statkraft plant, for example, has a capacity of about 4 kW. Now researchers have discovered a new way to harness osmotic power that they claim would enable a 1 m2 (10.7 sq. ft.) membrane to have the same 4 kW capacity as the entire Statkraft plant. The global osmotic, or salinity gradient, power capacity, which is concentrated at the mouths of rivers, is estimated by Statkraft to be in the region of 1,600 to 1,700 TWh annually. The Statkraft prototype plant (and a planned 2 MW pilot facility) relies on the first method, using a polymide membrane that is able to produce 1 W/m2 of membrane.
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• Energy Sources & Generation