If a failed Russian missile launch hadn't been confirmed as the instigator for those mysterious sky spirals, we would've seriously looked at this osmotic power plant in Norway as the potential source.
Statkraft, the company leading this project, has built a small-scale operation near Oslo in Norway, but hopes that it'll have a commercial plant built by 2015, which could generate power for 10 per cent of the country. If osmotic power plants were adopted throughout the world, Statkraft claims up to 1600-1700 terawatt hours could be generated, which is around half the energy that comes out of the EU currently.
Osmosis, if you cast your mind back to science class, is when a solution in water passes naturally through a semi-permeable membrane, separating the weaker solution from the strong.
In this particular Norwegian case, the membrane has been made from polyester, polysulfone and polyamide, and while some of the energy harnessed keeps the pumps ticking over, the rest of it powers a turbine - although currently, only one watt per square metre is being produced. It's believed that they'd need to generate five watts to make it worth its while, so it looks like it's back to the drawing boards for Statkraft for now. Wonder if they're related to the plastic cheese manufacturers? [Economist]