Real Water Power that could be the game changer

[markdansie]

http://hightechafrica.blogspot.pt/2012/04/pressure-retarded-osmosis-power.html

https://www.google.pt/search?client=opera&q=norway+osmosis+salt+sweetwater&sourceid=opera&ie=UTF-8&oe=UTF-8


"Statkraft estimates it spent over ten years and more than 100 million kroner (about $12 million USD) in research funds to help develop one of these techniques, pressure retarded osmosis (PRO), in the prototype facility at Tofte."


Much money,many days research : only for the functional prototype !


"According to Friso Sikkema, senior specialist in power generation and renewables at DNV Kema, the amount of potential energy contained in such processes is 'substantial'. The osmotic energy contained in 1 m³ of seawater amounts to around 0.75 kWh."

Thanks for the information.
I think this is where their calculations fall down given the power source is less than 1 kWh per cubic meter or ton of water. You can only extract what the power source allows. Like good triple junction solar cells can pump out kilowatts per square meter if the solar source is multiplied in intensity


Kind Regards

[tinman]

http://hightechafrica.blogspot.pt/2012/04/pressure-retarded-osmosis-power.html

https://www.google.pt/search?client=opera&q=norway+osmosis+salt+sweetwater&sourceid=opera&ie=UTF-8&oe=UTF-8


"Statkraft estimates it spent over ten years and more than 100 million kroner (about $12 million USD) in research funds to help develop one of these techniques, pressure retarded osmosis (PRO), in the prototype facility at Tofte."


Much money,many days research : only for the functional prototype !


"According to Friso Sikkema, senior specialist in power generation and renewables at DNV Kema, the amount of potential energy contained in such processes is 'substantial'. The osmotic energy contained in 1 m³ of seawater amounts to around 0.75 kWh."

You are referring to pressure retarded osmosis,where as Mark is referring to electrodialysis-two very different systems.

This new membrane that the guys Mark linked to,is far more efficient than the organic ones used today in the electrodialysis process. I think they were talking in Megawatts of power per square meter,not 0.75 kWh per cubic meter as with pressure retarded osmosis.

Quote: In reversed electrodialysis a salt solution and fresh water are let through a stack of alternating cation and anion exchange membranes. The chemical potential difference between salt and fresh water generates a voltage over each membrane and the total potential of the system is the sum of the potential differences over all membranes. It is important to remember that the process works through difference in ion concentration instead of an electric field, which has implications for the type of membrane needed.

So electrodialysis(the one Mark has posted) produces electricity via ION exchange-much like a fuel cell,where as pressure retarded osmosis creates a pressure that can be used to drive a turbine to produce power.


Brad

[minnie]

   Read on a bit more and see the natural battery, there they mention
  5 million square metres and in reality you'd probably need to at least
  double that!

[lancaIV]

You are referring to pressure retarded osmosis,where as Mark is referring to electrodialysis-two very different systems.

This new membrane that the guys Mark linked to,is far more efficient than the organic ones used today in the electrodialysis process. I think they were talking in Megawatts of power per square meter,not 0.75 kWh per cubic meter as with pressure retarded osmosis.

Quote: In reversed electrodialysis a salt solution and fresh water are let through a stack of alternating cation and anion exchange membranes. The chemical potential difference between salt and fresh water generates a voltage over each membrane and the total potential of the system is the sum of the potential differences over all membranes. It is important to remember that the process works through difference in ion concentration instead of an electric field, which has implications for the type of membrane needed.

So electrodialysis(the one Mark has posted) produces electricity via ION exchange-much like a fuel cell,where as pressure retarded osmosis creates a pressure that can be used to drive a turbine to produce power.


Brad

Probably !
http://www.nature.com/nature/journal/vaop/ncurrent/full/nature18593.html
Making use of the osmotic pressure difference between fresh water and seawater is an attractive, renewable and clean way to generate power and is known as 'blue energy'. Another electrokinetic phenomenon, called the streaming potential, occurs when an electrolyte is driven through narrow pores either by a pressure gradient or by an osmotic potential resulting from a salt concentration gradient. For this task, membranes made of two-dimensional materials are expected to be the most efficient, because water transport through a membrane scales inversely with membrane thickness

[lumen]

Makes me think the process could work the same way but in reverse using a simple reverse osmosis filter.
One could force saltwater through the filter and cause a charge difference to accumulate.