Ok where does the energy come from?

[bm0p700f]

http://www.statkraft.com/pro/press/Press_releases/2007/Statkraft_to_build_world_s_first_osmotic_power_plant.asp

Just heard about this on a UK T.V programme. It described an osmotic pressure power station described in the link above. It works by alternating chambers of "pure" and salt water, separated by a semi-permeable membrane. As water moves into the salt water chambers the pressure build until water is expelled driving a turbine. Great but where does all this energy come from?

 

[DavidSnider]

http://en.wikipedia.org/wiki/Osmotic_power

 

[bm0p700f]

The article goes over what I already know and does not address where the energy comes from. The ouput K.E of the tubine comes from somewhere. To say is comes from the pressure difference between the saline and pure water is not enough for me.

Can anyone eleaborate. Maybe I am asking the wrong question.

 

[A.T.]

The article goes over what I already know and does not address where the energy comes from.

Of course it does:

http://en.wikipedia.org/wiki/Osmotic_power]All[/PLAIN] energy that is proposed to use salinity gradient technology relies on the evaporation to separate water from salt.

Usually energy from the sun separates water from salt and can be retrieved by this technology.

 

[mgb_phys]

Ultimately the energy came from the sun evaporating sea water and dropping it on land as rain.
It's basically the same as hydroelectric power but instead of using the difference in height it uses the difference in salinity.

 

[bm0p700f]

OK, I just did not read it well enough.