Eco Factor: Pilot projects to generate renewable energy from water.
Renewable energy, which is currently dominated by solar and wind farms, is churning out power that is expensive and highly dependent on climatic conditions. Two companies are trying to develop an alternative that provides low-cost renewable energy by harnessing power from the clash of river and sea water.
The first to try harnessing osmotic power is Statkraft, Norway’s state-owned power utility, which is building the world’s first large-scale prototype facility for developing a form of salt power called pressure-retarded osmosis. The facility is expected to begin operation in Norway by the end of November.
The $5 million prototype will place fresh water and brine on either side of a semi-permeable membrane that allows water to pass but stops salt on one side. This generates pressure equivalent to a column of water 120m high. This pressurized water is then used to turn a turbine to generate electricity.
The other company trying to generate “salt power” is a Dutch firm called Wetsus. The technology relies on reverse electrodialysis, where a series of fresh and saltwater streams are pushed into underground pipes to opposite sides of two kinds of membranes. These membranes allow the passage of sodium or chloride ions, which builds an electrical current across the membranes.
Though both the companies won’t end up producing more than just a couple of KWs of power, they will demonstrate that their plants are scalable and commercially viable. Statkraft estimates that salt power can produce 10% of the global demand of electricity and since it doesn’t depend on climatic conditions and doesn’t require damming of waterways, it will prove to be a cheaper option than other forms of renewable energy generation.
Via: Scientific American
