China Turns to the Sea for Fresh Water | Hacker News Reader

China Turns to the Sea for Fresh Water

bloomberg.com

45 pointsSami_Lehtinen50 comments

Why not look at something like nuclear? Since the need is both electricity and heat, a nuclear reactor seems ideal since you don't have to convert power back in to heat - you can just use it directly.

With modern recycling techniques and reactor designs the chance of meltdown and wastes are limited, but that seems better than more coal.

Not an expert on reactor design vs desal design by any means - would love an opinion on the challenges here outside the standard nuclear ones.

Agreed. Particularly for California which has heavy energy and water needs, nuclear desalination seems like the most future-proof approach, particularly considering the dramatic decrease in aquifer volume as groundwater is extracted to make up for drought-level rainfall.

This seems to be a common fallacy: desal, which is being considered by a few wealthy urban water districts on the coast, will do absolutely nothing to alleviate overpumping by farmers in the Central Valley.

I think the goal would be to scale desalination efforts to the point where it can replace groundwater pumping statewide. This would come at a huge cost, sure, but once the groundwater runs out, the economics won't look so bad.

The largest desal plant I am aware of is in Saudi Arabia and produces about 830 acre-feet of water a day. Irrigation Central Valley averages 110,000 acre-feet a day, although there are significant seasonal differences. Let's (generously) pretend that you somehow had space in coastal California (not exactly something we have a lot of here, and certainly not cheaply) to build ~60 desalination plants, each double the size of the largest plant in existence. Let's completely ignore the multiple gigawatts of additional power you'd need to run these things. Let's pretend that you somehow convinced the Coastal Commission, EPA, DFG, Fish and Wildlife Service, and all the other relevant entities that intake and discharge from several dozen huge new desal plants dotting the coastline would not significantly impact the marine environment. (Ha.) Assuming all that were true, you would still need to pump roughly 40 million acre feet of water a year from the coast, towards the foothills, in the complete opposite direction which nature intended.

Never. Going. To. Happen.

Sorry to rain on your parade, but this blind, frequently uninformed faith that Technology will save us from anything and everything just gets annoying after a while.

Many places with water shortage are sunny and hot. In my mind it is the perfect use case for solar thermal power plants. I just love how simple they are. If we build coal or nuclear power plants, we just ditch one problem for another.

It is also a great way to smoothen the varying production of renewal energy.

That's an interesting idea as well. A molten salt reactor or something similar would have the same benefits as nuclear, you just trade reliability for cleanliness. I would imagine that a molten salt set up would be significantly cheaper to build as well, but I could be wrong on that.

A good thing is that you don't care about normalizing usage: if the plant happens to only work during the day, it's fine, you can make fresh water during the day and use your storage tanks at night. Unlike with batteries, there's basically no waste in storing water overnight.

In my experience working with one of the major players among Chinese nuclear power groups, nuclear power plants have low acceptance rate among local residents, perhaps even local governments, especially after Fukushima Daiichi nuclear disaster. If I recall correctly, there was some big plan in government's 5 year master plan at that time. Well, there are more factors come to play. What I mentioned is just one of them.

Israel (obv a different scale than china) has recently also experienced a big push toward desal. What's interesting is there's a moore's law type of effect at play here, desal keeps getting cheaper and cheaper to the point where it's actually a practical alternative to ground water, filtering etc.

I think water will be another great Malthusian disappointment, ocean water is basically unlimited (correct me if I'm mistaken), and on a 20-50 year time horizon it seems that the world should be able to alleviate all water scarcity by tapping it.

I suppose it depends on how hard it is to pump it uphill once it's out of the ground given that it starts at sea-level. Some of the more inland places or more uphill places might still be hard to get to with efficient desalination. Eg: Nevada

What will you do with the salts and various impurities?

Put it back in the ocean.

No...Most ocean life is ridiculously dependent on perfect salinity levels. We wouldn't be doing any favors by increasing these levels, no matter how small our impact may be.

won't the new fresh water get back to the ocean too?

There will be a phase lag and a concentration effect.

The change in salinity would obviously be negligible averaged over the ocean, and would be massively, massively dwarfed by other human factors. Your extreme use of the precautionary principle would prohibit essentially all new constructions, if applied widely.

Much more interesting is the question of the impact to the nearby ecology in the immediate neighborhood of the discharge pipe. I'm not familiar with this, but I'd wager it can easily be mitigated.

EDIT: Thank you to CHY872, who provides a link below to a review of the environmental impact of the waste water from desalinization:

> In most other cases environmental effects appear to be limited to within 10s of meters of outfalls.

http://www.ncbi.nlm.nih.gov/pubmed/20633919 suggests that they can be mitigated.

Add it to a large tidal river mouth and you just shift the mix point upstream slightly.

Dump it on the roads in the North during the winter.

Or, more seriously, if it is salt that was extracted from the sea, there shouldn't be much harm in putting it back. The fresh water that was extracted will end up back in the sea also, so overall there should be no increase in salinity (except locally where the salt is dumped).

There are other products that come out of the process with the salt. There is a good example of the Persian Gulf because of the number of installations and the ability to easily measure the increase in salinity and contaminants.

http://www.warponline.org/uploads/contents/103-content-9.-En...

Why can't we just eat the salt?

A liter of seawater has 35 grams of salts in it (I looked it up: http://en.wikipedia.org/wiki/Seawater ). Compare that to the recommended daily intake of several grams of salt.

It's also the case that most of the desalination methods produce concentrated brine instead of dry, clean salt (so extracting the salt would require further energy), but not needing that much of it is the bigger reason.

I didn't mean to drink it, I meant to turn it into table salt.

Seems like there ought to be some kind of further usage of it.. industrial or otherwise.

I got that. For every liter of seawater that is desalinated, there would be ~35 grams of table salt. On a given day a person might use 4 grams of salt.

Given typical water usage, you quickly have salt for an awful lot of people (salt for hundreds of people per person consuming the water).

I guess other users would be welcome, even if they just take it for free that probably saves the desal plant on disposal costs.

Considering drinking water is some tiny, tiny fraction of the world's water, it's probably not going to be a crazy idea to just dump the salt etc back in the oceans where it came from without causing any crazy imbalance, because we're talking about less than 1% of water.

About 2.5% of all the world's water is fresh water, and of that about 65% is in glaciers and icecaps. The roughly 0.8% of the world's water that remains, another 65% or so is permafrost and ice, only about 0.5% of the 65% of the 2.5% of the world's water is in river's for example.

See for example: http://water.usgs.gov/edu/pictures/watercyclekids/worlds-wat...

So the notion of taking a small fraction of the ocean, desalinating it, and dumping the rest back in the ocean (as will eventually the water itself, later on in the process) probably isn't a big deal.

But then it's just inference, I'm not intimate with the subject. Biggest hurdle for me was always that desal was crazily energy intensive. I can't imagine it's become orders of magnitude more efficient, and as energy costs didn't plummet on such a scale (orders of magnitude), I thought it'd still be. But it turns out the costs are dropping fast.

I mean, I can easily see desal working for drinking water & cooking (few litres a day) for everyone on earth, but things like agriculture are a whole different beast. A kilo of wheat for example averages over 1.000 litres of water, while meat can go all the way up to 20.000 litres. I can't imagine desal for the billions of farm animals we slaughter every year (yes, billions :-/) , each weighing tens if not hundreds of kilos, for example, or even just agricultural production.

I'd be happy to be enlightened!

This is emphatically not true. The salinated impurities that are a byproduct of this process will kill everything in the zone that is is reintroduced to. Just because it is a small fraction of the ocean doesn't mean we can easily spread it across the entire ocean. Even then, we are doing an irreversible transformation of the ocean as a whole, and we need to be smart about the waste for the process to be sustainable.

I can think of several countries that did this incorrectly and killed large portions of their coastal ecology as a result.

Well, if you can think of them, can you type their names out and share them perhaps?

Or are you generally referring to pollution rather than disastrous desalination attempts?

> The salinated impurities that are a byproduct of this process

That's a very inaccurate way of saying that. You are implying that that desalination creates new byproducts. It does not. Any byproducts were already in the ocean.

You just run your outflow pipe far into the ocean, and mix it with ordinary seawater and it's sufficiently diluted.

That's misleading. It's not technically a byproduct, but taking literally tons of salt that was spread evenly throughout the ocean and dumping it out at high concentration at the end of a pipe has significant (and bad) ramifications for the ecosystem at the end of the pipe.

Nobody said to dump it out a pipe at one single point. Spread it out leaky pipe style over a large volume of ocean so that the average salt concentration does not significantly rise.

Many desalination plants mix it back into the ocean, you pump more water than you are desalinating and the 'waste water' is a mixed brine at an acceptable salinity level.

That said with global warming melting a bunch of fresh water glaciers into the ocean, one of the side effects is lowering the salinity level. This suggests to me that boosting it slightly by desal efforts will be negligible at worst, and remediation at best.

And of course the quantities we're talking about are pretty much mouse nuts with respect to the entire ocean. But an interesting question to play with is when does a 'keystone pipeline for water' make sense? Clearly Boston would have not minded shipping snow to California to get rid of it this winter. China is working to reroute major water ways, could we manage flood levels on the Mississippi that way? I don't know but it is fun to imagine.

> That said with global warming melting a bunch of fresh water glaciers into the ocean

That's a very good point! Potentially desalination could help fixing problems of rising see levels too. There are many deserts that could become huge lakes (in Sahara, Persia, China) and eventually it should be possible to move enough water from sea to compensate for some of polar ice melt.

Less mining.

Looking at price trends of desalination and solar power leads to the conclusion that by 2050, the 100km coastal region everywhere could have access to affordable water, and by 2040 in the western world[1].

Personally i think that water consumption will greatly decrease in the future, because of the great water saving potential of synthetic biology as a way for growing food:

In theory using synthetic biology and making basic food components[amino acids, fats, flavourants, etc] can make all the food the world eat, at a land size of rhode island with something like 1/1000 less water than today, generating around 1% of greenhouses gases , and at something between 5-20 cents/pound.And molecular gastronomy and food science know, or are rapidly learning,how to make it into tasty food.

As an example for that, there's a company(prottero) that uses synthetic biology, and already making sugar at 5 cents/pound - 1/2-1/3 of the cost of regular sugar, with 30x the land efficiency.

So yes, i think Malthusians will be very disappointed.

[1]http://www.syngentafoundation.org/db/1/1299.pdf

How crazy would it be to (Mostly to help the American Southwest, though if it worked, it could be used anywhere that uses river basins as a major source of freshwater for extremely large areas) create a large pipeline to feed an inland desal plant that's located along the shortest, lowest, least populated path to the headwaters of multiple major freshwater sources, like the Colorado and Rio Grande and the pump desal water into the existing water distribution network?

While it's a major geoengineering project (musk-scale!), it would allow for usage of current legal and physical water distribution to be reused.

Also, while CA desal cites briny outflow disposal as a major impediment to desal, why not pump the outflow to existing salt flats?

(Edited for clarity)

Maybe they can export their excess freshwater in giant tankers to CA to solve their drought problem. They already produce most of the electronics we consume.

If that were reasonable then we would tank water in from Alaska. Or China would buy AK water.

If you want to dream big, in the 1980s there were pipe dreams of bringing in water from the Copper or the Stikine through a large off-shore pipeline to California.

There have been serious proposals to ship Great Lakes water to Asia. This article mentions one:

http://www.wbez.org/frontandcenter/2011-06-21/great-lakes-fa...

There is now an agreement placing tight limits on what happens to the water:

http://en.wikipedia.org/wiki/Great_Lakes%E2%80%93Saint_Lawre...

There's serious and then there's serious.

Fiji exports water to the US. I've heard of a bagel company in London which imports its water from New York City. People buy ice that comes from Alaskan glaciers. (Minor note: If you use under 20 tons/year of tidewater glacier ice then you don't need a permit.) So people are willing to pay a lot of money for provenance.

Fiji Water is a good comparison. According to its Wikipedia page, it was exporting over 15 million liters/month. According to others, it was a least 3.5 million liters per month. According to http://www.alternet.org/story/101207/the_true_price_of_fiji_... it was 130 million liters in a year. I'll say it was 5 million L/month or 60 million L/year.

According to the Wikipedia page for "Water export", the Great Lakes -> Asia deal was for 600 million liters, or about 10x of what a single well in Fiji can provide.

Oil shipping costs something like $1.20/barrel from Qatar to Rotterdam, says https://books.google.com/books?id=cUHAAgAAQBAJ&pg=PA232&lpg=... . A barrel is 120 liters, or 1 cent per liter shipping costs.

That's about $12 thousand per acre-foot. The price of desal water is under $3,000 an acre-foot.

If the goal was to market provenance - the Fiji Water of Asia - then it might be profitable. It otherwise doesn't seem like a serious proposal.

If there were a were serious need, then I would expect to see water exports from Alaska, which allows bulk water exports (again, according to the "Water export" page at Wikipedia) and is a lot closer to Asia.

Since there isn't, I have difficulties understanding how there's a serious proposal.

There certainly isn't a serious existing proposal, there is a series of agreements making sure it isn't done.

I was just saying that someone had thought about doing it, enough so that they went ahead and got a permit.

I wonder what the prices for shipping and desal were in 1997...

Oh, I agree. I was just saying that there's "serious" and there's "serious"

http://www.greatlakeswaterwars.com/chapter11.htm says that it was a for-profit "humanitarian effort on behalf of the world’s poor that was also designed to make money".

I can't figure out how it was supposed to work. It looks like it comes down to person who wanted to do it was in Sault Ste. Marie, Ontario, and thought of the tons of water in the backyard [paraphrasing]. So he and his partners could have been serious about, but there's no real chance it would work out.

It doesn't really matter what the prices were in 1997. Alaska water is closer to Asia than the Great Lakes. If it made sense for Lake Superior, it would make even more sense for water from the Sitka.

http://www.heatisonline.org/contentserver/objecthandlers/ind... says that around the same time :

> A company called Global Water Corp. has announced plans to ship up to 5 billion gallons a year of glacier water by tanker from Alaska, near the port city of Sitka, to the Middle East. The company said on its Internet web site that it has reached agreements with buyers in China, and that it plans to negotiate with interested parties in the southwest U.S.

There's a lot of people who talk, in the hopes that someone else will front the money. It's not really a con, because it might actually work. But if things are borderline, it can help to sound serious and express no doubts.

China already imports a vast amount of California's water via produce (eg their consumption of California almonds), so to be accurate it would be more like them sending the water back.

"the facility will remove salt from 120,000 tons of seawater each day. The result will be 50,000 tons of potable water"

Huh? What happens to the other 70,000 tons of water? Or do they mean it will take in 120,000 tons, use something (e.g. distillation, filtering) to move almost all the salt in it to about half of it, and get 50,000 tons of potable water and 70,000 tons of about twice as salty as the input water?

You are correct. The energy cost to desalinate increases as the salt content increases, eventually you have to let it go.

This has been mentioned elsewhere, but I wonder if we could use the super large tankers that are currently being built for transporting oil and gas for transporting water instead? There is tons of fresh water in the great lakes and the polar ice caps.

These ships don't need all the advanced machinery that they currently have for making sure there is no leaks: if there are minor leaks, its water anyways. So its likely to be much cheaper.

I'm concerned about the amount of fossil fuels they would consume though.

Is it enough? I'd imagine the amount of water used (industrial, residential, agricultural) is far greater than oil. For example -- ~3k gallons water / lb of beef. That means growing a cow uses A LOT more than the cost of transporting that beef once it's slaughtered.

Wouldn't be worth it.

The largest super tankers have a deadweight tonnage of approximately half a million tons, which is worth ~$500MM of crude oil.

But water is super cheap by comparison. Assuming $0.0015/L (which is what I pay for my tap water in California), half a million tons of water is worth only $750k.

Another way to see it: the transport cost per super tanker is about $0.02 per gallon [1] but tap water is ~$0.006 per gallon (again, my tap water cost). So you would be tripling its cost to transport it by sea...

[1] http://en.wikipedia.org/wiki/Oil_tanker

California has big plans for desalination too

http://www.mercurynews.com/science/ci_25859513/nations-large...

Desalination uses TONS of electricity. Where does that electricity come from? Fossil fuels. So this "solution" to water shortage actually increases global warming, which will worsen water shortages. And what happens with all the extracted salt? You guessed it - it goes right back, increasing the salinity of the oceans.

Ah, humans.

But hey, technology solves all problems, right YC?

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