- Salinity gradient
Salinity gradient power or osmotic power is the energy retrieved from the difference in the salt concentration between
seawater and river water. Two practical methods for this areReverse electrodialysis [Power generation by reverse electrodialysis [http://mtg.tnw.utwente.nl/teaching/assign/blue/] ] (RED), andPressure retarded osmosis [How does PRO work? [http://www.statkraft.com/pub/innovation/osmotic_power/osmotic_power_in_brief/the_pro_concept.asp] ] (PRO).Both processes rely on
osmosis with ion specific membranes. The key waste product isbrackish water . This byproduct is the result of natural forces that are being harnessed: the flow of fresh water into seas that are made up of salt water.The technologies have been confirmed in laboratory conditions. They are being developed into commercial use in the Netherlands (RED) and Norway (PRO). The cost of the membrane has been an obstacle. A new, cheap membrane, based on an electrically modified
polyethylene plastic, made it fit for potential commercial use [History of osmotic power [http://www.statkraft.com/Images/Faktaark%20OSMOTIC%20ENG_tcm4-7797.pdf] ]References
ee also
*
Electrodialysis reversal (EDR)
*Reverse osmosis
*Semipermeable membrane
*Green energy
*Renewable energy
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