The plant will generate about 880,000 kilowatt hours of electricity per year—enough to help run a nearby desalination facility and supply around 220 homes. That equals the output of two soccer fields of solar panels, but osmotic power keeps running day and night, in any weather.
Using it to run desalination is confusing.
Technical explanation : with reverse osmosis you have :
(salty water + energy )
→ ( fresh water + highly salty water )So, reverse this process (call it osmosis plant ?) and you get energy … e.i. :
( fresh water + highly salty water )
→ (salty water + energy )I think it’s more like:
(salty water + unpotable fresh water) → (salty water + potable fresh water + energy)
…with a few steps in between. Even if most of the power is used in running the plant, you end up with potable fresh water and no brine being dumped into the ocean, which is a net win.
I think the article author is completely confused and doesn’t understand what’s happening. There are hints of what’s happening in this paragraph.
Fresh water—or treated wastewater—is placed on one side of a membrane. On the other side is seawater, made even saltier by concentrating leftover brine from a desalination process. The difference in saltiness pulls the fresh water across the membrane, increasing the pressure on the saltwater side. That pressure is then used to drive a turbine, generating electricity.
I don’t think any fresh water is being used. I think what’s actually happening is…
Very salty wastewater (from the desalinization plant) is placed on one side of a membrane. On the other side is seawater. The difference in saltiness pulls the wastewater across the membrane, increasing the pressure on the saltwater side (or maybe the other way around). That pressure is then used to drive a turbine, generating electricity. The waste then is just water that’s saltier than sea water, but less salty than what came from the desalinization plant.
Yeah, it’s just recovering a little of the energy spent in desalination, making it slightly less energy consuming.
So it’s a turbo engine.
Why isn’t it fresh (non-salty) wastewater?
Lots of places treat their wastewater and then discharge it. For example, where I live, wastewater, that is to say, sewage which has had solids filtered out, is still rather pooey and pissy but not salty, gets treated (I don’t know how) and is then injected into natural underground aquifers where it eventually percolates out to bores or springs where it’s collected and used for irrigation, contributes to natural springs, or possibly even winds up in a drinking water catchment.
All wastewater, regardless what happens to it, has to be treated before release. If it’s still 99.9% fresh, then why not use it to create osmotic pressure before dumping it.
There*
Friggin hell. Thanks.
Based on the limited power generated I wonder if we can do something similar with cola and menthos.
Wow, I did not even think of that! This guy sciences!
