This seems like a terrible use, since these plants work by mixing fresh water with seawater (or in this case the brine leftover from desalination). I guess the catch is they can use treated wastewater instead of potable water.
This method gains very little net energy compared to other renewables.
“While energy is released when the salt water is mixed with fresh water, a lot of energy is lost in pumping the two streams into the power plant and from the frictional loss across the membranes. This means that the net energy that can be gained is small,” said Kentish.
Returning to this thread long after everyone has moved on.
How do you get enough net energy out of mixing brine from desalination with fresh water to use to separate saltwater into brine and fresh water? Especially when the energy producing method is already known to have poor efficiency?
This seems like this is just terrible at converting treated wastewater into drinking water. Must have something to do with government subsidies instead.
underline960@sh.itjust.works 4 days ago
Why do it, then?
Is this a proof of concept/MVP build, so they can iterate more efficient versions? A vanity project? A mistake?
thebestaquaman@lemmy.world 4 days ago
Because osmotic power has enormous potential in the sense that millions of cubic meters of fresh water is running into oceans all over the world every minute. If we’re able to get even a low-efficiency method of using the salinity gradient to generate power working then every place a river meets the sea is essentially an unlimited (albeit low-yield) power source.
This is tech that doesn’t rely on elevation (like hydropower) or weather conditions (like wind/solar) it’s stable and possible to set up at pretty much any river outlet, which is great!
tyler@programming.dev 4 days ago
Gotta be careful about ecosystems though. River deltas are incredibly important and fragile areas.
BowtiesAreCool@lemmy.world 4 days ago
Dams 2.0
thebestaquaman@lemmy.world 3 days ago
Oh absolutely. As with all other infrastructure, there is a cost to be paid. However, when you look at an average to small river, even routing 10 % of the water via an osmosis plant before passing it to the sea is an absolutely massive volume. There’s also the point that you don’t want to build these things in large, meandering, flat river deltas. You want a large salinity gradient, which means relatively small, fast-running fresh water meeting the ocean more “suddenly” than what you get in a classical river delta is the optimal source here.
GreyEyedGhost@lemmy.ca 3 days ago
Turning unpotable water into potable water with little or no additional cost, while not harming the environment, isn’t exactly a loss.