GC: n
CT: Salinity power is one of the largest sources of renewable energy that is still not exploited. The potential power is large, corresponding to 2.6 MW for a flow of 1 m3/sec freshwater when mixed with seawater. The energy released from 1 m3 fresh water is comparable to the energy released by the same m3 falling over a height of 260 m. The exploitable potential world-wide is estimated to be 2000 TWh/y. The potential cost of energy from this source is higher than most traditional hydropower, but is comparable to other forms of renewable energy that are already produced in full-scale plants. The availability and predictability of salinity gradient energy is much higher than intermittent renewables like wind and sun and therefore sustainable base load energy.
S: http://www.oceanenergy-europe.eu/index.php/13-technology/46-salinity-gradient (last access: 10 February 2015)
N: 1. salinity (n): 1650s; see saline (adj. “made of salt,” c.1500, probably from a Latin word related to salinum “salt cellar” and salinae “salt pits,” from sal (genitive salis) “salt”) + -ity (suffix forming abstract nouns from adjectives).
gradient (n): “steep slope of a road or railroad,” 1835, principally in American English, from grade (n.) by analogy of quotient, etc. It was used 17c. as an adjective, of animals, “characterized by walking;” in that case probably from Latin gradientem, present participle of gradi “to walk.”
energy (n): 1590s, “force of expression,” from Middle French énergie (16c.), from Late Latin energia, from Greek energeia “activity, action, operation,” from energos “active, working,” from en “at” + ergon “work, that which is wrought; business; action”.
Used by Aristotle with a sense of “actuality, reality, existence” (opposed to “potential”) but this was misunderstood in Late Latin and afterward as “force of expression,” as the power which calls up realistic mental pictures. Broader meaning of “power” in English is first recorded 1660s. Scientific use is from 1807. Energy crisis first attested 1970.
2. At the interface of fresh and salt water where rivers enter the sea or at the interface of waters of different salinity, osmotic pressure occurs which may be exploited to provide useful energy by the application of suitably disposed semi-permeable membranes, for example, in the form of a closed cylinder. Alternatively, the electrochemical potential at the interface may be exploited to generate electric current directly.
S: 1. OED – http://www.etymonline.com/index.php?allowed_in_frame=0&search=salinity&searchmode=none; http://www.etymonline.com/index.php?allowed_in_frame=0&search=gradient&searchmode=none; http://www.etymonline.com/index.php?allowed_in_frame=0&search=energy&searchmode=none (last access: 10 February 2015). 2. GDT.
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CR: ocean energy
