Japan has opened its first osmotic power plant
theguardian.com
theguardian.com
The end result is that the salty wastewater is partially diluted, which means it has a lower environmental impact when it is discharged to the ocean.
thanks
It's making desalination more efficient and the effluent a bit easier on the ecosystem.
They do hint at it at end:
> “It is also noteworthy that the Japanese plant uses concentrated seawater, the brine left after removal of fresh water in a desalination plant, as the feed, which increases the difference in salt concentrations and thus the energy available.”
And the "fresh" water is also "treated wastewater". That could mean a bunch of things but in most cases it's water that's released into the environment by the water treatment plant. Its quality can be as good as clean water, but most municipalities wouldn't feed that right back to the consumer, they dump in a river or lake instead.
From what I understand most municipalities do not directly feed sewage treated water right back to the consumer, normally they dump it into a lake or river first. A lot of that may just be an informal "yuk" factor not necessarily not having the technology.
It's cool but everything sort of has to be aligned for it to work well.
Also it is kinda hard to sell to people the concept of “you are drinking literal shit/piss” even though if you stop and think about it all lake/river/reservoir water is full of fish, bird, etc shit.
The article also doesn't say if it produces more power than the attached desalination plant requires. I doubt it as you'd be getting close to a perpetual motion machine if so. In which case basically what you've got is a very energy efficient desalination plant, more than a power plant.
The osmotic power plant generates about 100kW, so it's about 5% of the total desalination energy requirement.
If you have a better estimate, feel free to supply it.
That being said it's a first so it's a pilot project needed to have feedback on a real plant in operation and not just back of the enveloppe calculations and suppositions. Sometime you need to just build the thing to encounter problems, issues or non-issues.
1. https://www.niph.go.jp/soshiki/suido/pdf/h21JPUS/abstract/r9...
Not really. Even if it would generate enough to power the plant, it would still rely on work being done outside of the plant, i.e. the flow of semi-treated waste-water and possibly the brine itself.
In fact, it almost seems that you could simple pull in sea water as the “low salt” water and still have a large enough delta against a brine solution.
Really interesting that it also solves the brining issue.
I am kind of curious on how much you can/should optimize this process until it becomes dangerous or unmaintainable. And can we do this on more places on this planet? For instance somewhere on a desert coast or something? Could be cool to build some of those between Sahara desert and the ocean, combined with solar panels or something.
It is more like it slightly reduces the power required to run the desalination process
But, if it’s in any way efficient, why not just use some of the fresh water you produce? Doesn’t that kinda become free power in a sense?
Using fresh water to power a desalinization plant just seems counterintuitive to me, I guess, but maybe (certainly) I’m misunderstanding something
100 kW, in sensible units.
Probably this thing peaks at 120-150KW which isn’t going to fix the grid.
If you have an average of MWh a city needs, having MWh is a helpful metric, as well as kW to make sure you can power the city on peak consumption. No?
See also, "Power is not Energy": https://youtu.be/OOK5xkFijPc
But if you happen to know that a typical person in a rich country like you're probably in (5th percentile of the world population) uses about 1.5 MWh/year, I guess you can also approximate a MWh figure by saying 1 MWh/year is close enough, so I'd understand if someone says that works for them
> a typical person in a rich country [...] uses about 1.5 MWh/year
That's just electricity, not energy. The real figure is probably ballpark 50 to 100 percent higher (probably mainly depending on climate for heating/cooling demands and the heating method being used) but I haven't looked that up now. Just wanted to remark this (can't edit anymore) so it's no longer completely misleading
This system depends on using a LOT of energy to maintain an osmotic pressure gradient. That it turn depends on pumping water across a boundary. Energy has to be expended. Now, if you run a de-salination plant and/or waste water treatment you have to expend MOST of this cost anyway, so you are scavenging energy back from an unavoidable, non-externality cost.
This is a big difference. Wind and Solar bring energy in from the Sun and weather, outside human expenditure. This brings BACK some expended energy, doing another job.
I suppose hypothetically, given immensely saline water CLOSE to less saline water you could expend significantly less energy to arrive at the boundary condition but its for kilowatts, not gigawatts or even megawatts. The places which have these conditions might also have high sunlight or wind conditions no?
1. I take a shower and produce non-salty waste water
2. That waste water and brine from a desalinization plant can be used in this plant.
3. The result is concentrated waste water and less salty brine and some power
4. The power can be used to (partially) power the desalinization plant produces fresh water from sea water and brine.
5. I get fresh water for my shower.
And the diluted brine from step 3 goes to the sea? Or can it be run through the desalinization plant again? Does concentrating the waste water in step 3 also help with the eventual treatment of it
I imagine someone out there does a cost-benefit analysis to compare this system to just fully treating and reusing the wastewater and thus needing to desalinate less saltwater.
The concentrated waste probably gets disposed of rather than trying to get the remaining water. You treat it like the results of a waste treatment plant. You might dehydrate it a bit, just so you don't have to ship the water, but you probably won't try to recover any more water than you already have.
On the other hand, there are often restrictions on how concentrated your brine can be when released so it doesn't cause environmental problems. If you have to dilute your brine anyways, might as well get a little energy back.
I notice the 'some' here, and the absence of the word 'nuclear' from the article, which of course is also available around the clock. Most readers will know something about Japan's troubled relationship with nuclear power and can fill in that context themselves, but to my eyes, it's a startling omission.
Renewable, to my mind, means energy that will be there in a million years. Solar. Wind. Waves. That kind of thing.
If you don't like that, then there's also concentrated solar. We're not going to run out of mirrors.
Fissile isotopes on the other hand, once they're gone, they're gone. You can build new reactors that run on different fuel but that's not the same thing as you were doing before, so you can't call the original process renewable.
It takes 18.6 tons of natural uranium to produce 1 TWh of electricity with light water reactors.
The world consumes ~30,000 TWh each year.
65 Trillion / (18.6 * 30,000) = 1x10^8 years worth of uranium with present day technology, no elves required.
Think we can figure out breeder reactors in 180 million years? If we're going all nuclear, I'd expect them in under 1,000 years, but I'm not an expert.
> The European Commission said in 2001 that at the current level of uranium consumption, known uranium resources would last 42 years. When added to military and secondary sources, the resources could be stretched to 72 years. Yet this rate of usage assumes that nuclear power continues to provide only a fraction of the world's energy supply.
https://en.m.wikipedia.org/wiki/Uranium_mining
Or depends also on what we're willing to pay for the power but critics already call it too expensive compared to be viable given renewables' price and price history
The estimate is outdated but I didn't quickly find newer info and it's just generally not a weird notion to say it's exhaustible
Imo we should make use of what we have and not wait for everyone to put solar on their roofs to supply like 10% of what we need and then wonder how else we're going to reach net zero (especially in local winter), but that's another discussion
- breeder reactors will not exist in time
- we will not find more uranium on Earth than we have already
- we will not be able to economically extract uranium from seawater, phosphate minerals, coal fly ash or other sources
- other materials besides uranium will not be used in the future
- synthetic production will not become viable
To say that nothing will change in the next 40-70 years and we will simply run out of material and stop using nuclear altogether, just seems quite far-fetched in my opinion.
1) It's expensive. Very very expensive.
2) It's dangerous when not operated properly, and I don't trust commercial interests operating hundreds of these due to this reason.
3) It's bad for the environment, both the mining to get the uranium and all of the processes to turn it into fuel.
4) There is no answer for spent fuel.
Whereas with solar or wind you can basically remove #1, #2, and #4, however you still have to mine and process the materials.
Anyways, nuclear will be great for some niche uses, I am sure, but it isn't the answer to our green energy prayers.
There was some rule, that the cost of safety (like how thick concrete should be in some places), could be so high, that the usually cheaper fission energy would be equal in cost with the other sources (like burning oil). Then came the oil crisis of the 70's in USA. The safety margins got boosted to crazy levels, without any realistic gains. Moving from 99.999% to 99.9999% safety (just an example).
When the oil prices dropped, safety standards stayed and now fission energy is expensive. At least in USA and EU. Not in France or South Korea, which streamlined the regulations.
2) not with the modern technology, it isn't. And there are even safer alternatives like marble balls reactors that can't meltdown even if cooling is shut down.
3) not using it is bad for the environment. Fuel requirements are minimal compared to other plants. Even some types of renewables pollute more per W of energy produced. Like wind turbines that will fill up landfills at some point.
4) Thorium reactors. If we just give the fission energy some research & development, we can burn all the spent fuel up in thorium reactors.
It’s not economically viable. No amount of (ugh) Jordan Peterson whining will change that.
You add tariffs and you make steel production profitable in US. China subsidizes it's electric cars industry and they can sell EVs in Europe for half the price of European cars, literally killing the market.
You subsidize renewables heavily and you get windfarms that are unprofitable once subsidizing ends.
I'm sure that in a free market situation, your comment would make lot of sense. But this is not the case and you should read up a little.
I believe that one should aim to, in spite of their political views, try to see the big picture. Like why there's so little nuclear vs sun or wind.
Let me know, specifically, which of the safety measures you think we can skip, with your extensive knowledge.
Bag in/bag out was developed for labs handling infectious micro-organisms. It involves a complicated bagging system, which, if done properly, isolates a contaminated filter from the environment during filter change outs.
But for nuclear the bag only protects from alpha particles and electrons. It has zero impact on photon dose. If workers are wearing bunny suits and respirators they are already protected from alphas and electrons. The extra change out time required by Bag In/Bag Out increased the worker photon dose.
This regulation actually increases workers’ exposure to radiation.
This strategy was proven decisively correct in 2022, and also applies to solar and wind when the US (and by proxy, the whole West) inevitably gets into it with China and suddenly your degrading solar panels and growing need for energy become major problems (and thus forces you to build out nuclear anyway).
Cost isn't the only factor here, and it would be short-sighted to take the cheaper short-term option by buying Chinese rather than paying our own people to regain and retain that engineering and construction experience we foolishly squandered 30 years ago.
We store it. There are radioactive waste storage sites in 39 US states, for example.
https://curie.pnnl.gov/system/files/SNF%20and%20Rep%20Waste%...
And if humanity can’t do anything that it hasn’t done before, why should we care about power generation or any problem that wasn’t completely solved before today? (Like today. The day that you are reading this.)
Why are you so irrationally anti-nuclear?
Also, France has a state-owned company operating the plants. I would not be averse to an American version of that, or perhaps just expand and enhance the training they already do for the naval nuclear power program and send navy nukes to operate them. I don't trust American corporations to operate them properly.
“Nuclear waste makes me nervous” is not proof that we have dug up everything that has ever been buried.
Given the (possibly intentional?) inability to parse language here, to make sure that you’re not a bot, is it possible for you to answer the question? If yes say yes and then answer it, if no just write something vaguely anti-nuclear
Also, this line of inquiry is still just tilting at windmills; "somehow, future Fred Flintstone manages to get a hold of equipment capable of digging out a mile of concrete and yet somehow not know what radiation is" is not a productive line of thinking at best and a bad-faith argument at worst.
Humanity's mechanical capacity to dig that deep actually post-dates its discovery of radioactivity, too. If they have the technology for it for them digging it up to become an issue, they'll be able to identify, trivially, that it is an issue.
1. https://fragelada.fysik.org/index.php?amne=Energi&stage=&key...
The region is humid and rainy for over half the year and it's only particularly dry for about a quarter of the year. And they have a comprehensive system for evacuating stormwater during the rainy season as well.
So I'd reason a guess that they have a waste water excess 1/2 to 3/4 of the year but still need the baseload capacity of the desalination plant for the remaining chunk of the year. And while you could probably switch over to plain seawater for the portion where you are running negative, it may not be worth the added maintenance/cleanup cost of having to deal with salt or brackish water for only a small portion of the year. So instead you just eat the losses for that window in exchange for the increased efficiency/lower complexity/lower operating costs.
I hope this is just meant to be a tech demo, and doesn't have any advantages of scaling yet.
Maybe there's a cultural reason why Japan is more aware this is a thing that exists? Dunno
As an imperfect car analogy, the way a turbocharger uses energy from the exhaust to inject energy into the intake, in the form of compressed air.
Neither is a perpetual motion engine, but both make the useful work more energy efficient.
It's achieved by extracting some energy from the dilution process of waste salty brine with freshwater before dumping it to a river.