

MIT investigates power generation from the meeting of river water and seawater - vidyesh
http://newsoffice.mit.edu/2014/energy-from-salt-water-0820

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olau
There was a prototype salt power plant in Norway that eventually was
abandoned:

[http://en.wikipedia.org/wiki/Statkraft_osmotic_power_prototy...](http://en.wikipedia.org/wiki/Statkraft_osmotic_power_prototype_in_Hurum)

The competition in energy generation is fierce.

For those wondering how this works, basically when you have two liquids with
different salt concentrations separated by a semipermeable membrane, the
liquid with the lowest concentration tends to get pulled into the one with the
higher concentration - this builds up a pressure difference that can be used
to drive a turbine.

Interestingly, the same thing happens in living organisms - saltwater fish
loose water to the sea so they would dehydrate if it weren't for special
precautions, while freshwater fish have the opposite problem, they would end
up too diluted if their body didn't have means of getting rid of the excess
water.

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dmritard96
some of the most vital and complex ecosystems, responsible for huge amounts of
life on the planet. I think I would rather look elsewhere.

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marcosdumay
Most of the potential comes from temporary streams where rain gets into the
ocean, and those smaller water streams are just easier to deal with.

You don't need huge dams when you can only process a (relatively) little bit
of water per m^3 of plant.

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johnvschmitt
Unfortunately, even if this works, it will likely have less and less
application over time. California has very little fresh water reaching the
ocean, and as population increases, and drought increases, we're sending less
fresh water to the ocean.

And, over time, it takes more & more energy to make water fresh/clean in the
first place, and to move fresh water around.

So, any power generation scheme that requires using fresh water is not on a
good trajectory. It's good science experimentation though, & may spark other
more useful ideas.

