[joshe]

Advances are always welcome, but it's worth noting that desalination works economically right now.

In the last 15 years large scale desalination has become practical. It's one of the great engineering feats of our time.

We can now generate it at scale for less than $.01 per 6.4 gallons. This includes the cost of the electricity, which is about half the expense.

San Francisco charges $.02/gallon to residents, 12 times that price. It's now cost effective for any coastal city in America to supply residential water this way.

Lots of people still think desalination is still impractical, because it was 20 years ago. They just haven't learned about the new tech.

The tech:

https://www.energymonitor.ai/tech/can-desalination-save-a-dr...

Residential rates:

https://sfpuc.org/accounts-services/water-power-sewer-rates/...

[sandworm101]

Residential water is not the issue, not even commercial water. Desalination still doesn't work for the vast majority of users: agriculture. 0.02$/gallon is far to expensive when farmers need acre-feet of water (300,000 gallons). Delivery of such quantities from the ocean to inland farms is also impractical, and cannot conceivably be made so. That's why they draw from rivers and aquifers.

[ImHereToVote]

I think evaporating large areas of salt water could increase the local air moisture level substantially. That with the passive desalination could make water much cheaper in coastal areas.

[seltzered_]

It's also worth asking how desalination can be used in say afforestation or ecosystem restoration, to improve evapotranspiration of water over a landscape where appropriate.

I recall the CEO of terraformation (Yishan Wong) talking about using desal with brackish wells : https://www.terraformation.com/blog/solar-powered-desalinati...

[ac29]

In the US, thermal power generation is actually a bigger user of fresh water than agriculture: https://labs.waterdata.usgs.gov/visualizations/water-use-15/...

This is 2015 data. Not sure if the rapid rise in solar and wind has changed this, though it might over time.

[AtlasBarfed]

300,000 gallons, .01/6.4 gals

so .01 * 300,000/6.4 is... $500.

How often do they need the water?

[myfavoritetings]

That's 500 for one acre so multiply by 300-400 for a typical farm and it cuts into already fairly small margins on farming

[sandworm101]

Corn will need about 24" of water each crop. So, if there is no or little natural rain, two acre-feet of water per acre. There is no concievable method of transporting such amounts inland. It would require energy enough to reverse the flow of rivers.

[depressedpanda]

For the international audience who don't use freedom units, 6.4 (US) gallons is ~24.2 liters.

[xhainingx]

And $0.01 is ~€0.01

[avmich]

Freedom units?

[promiseofbeans]

A joking way to refer to the American units of measurement - feet, gallons, pounds, etc.

It's a commentary on all the unique and interesting ways Americans appear to measure things.

Sometimes people will take it further by, for example, converting a length in meters into football fields or bald eagle wingspans.

[avmich]

The confusion comes from naming American units "imperial" - after British, and having international - metric - system created by the French revolution, with "liberte" an important goal. So it could be argued that it's actually SI which has freedom units. On the other hands, Americans are quite often characterized as freedom "distributors"...

[jdblair]

The American system is called "customary units." The pint, quart and gallon are all smaller than British imperial versions.

[kwhitefoot]

Most Americans that I have pointed this out to look at me in disbelief. The vast majority have never heard of US Customary Units. Whenever they refer to their system of measure they say imperial, and many are unaware that volume measure in the Imperial system is different from US Customary. I fought again the use of imperial as the name for the system for over twenty years in a multinational company to no avail.

[jrmg]

American units of volume are different (most smaller by about 20%) to Imperial units.

[civilitty]

American, Liberian, and Burmese.

Can’t leave out our fellow beacons of freedom!

[interestica]

I've never met a Canadian who gave their height or weight in metric units. Or a recipe in Canada that doesn't set a temperature Fahrenheit. Also: the size of TVs and screens. Or paper.

[edgineer]

Myanmar has moved to metric

[NikkiA]

And liberia is in the process of doing so, but so is the US technically.

[phanimahesh]

News articles in particular tend to go out of their way to use strange units of measurement. Bananas, fishes, football fields, car lengths, swimming pools... Anything but SI system of units. Even the feet gallon pound values are rare finds that need perseverance.

[cagenut]

my least-favorite is describing every energy project by the number of "homes" it can power

[michaelteter]

Eagle wingspans isn't something I've seen used, but the football fields unit does make sense when talking about something which is relatively long (can be measured in 1/2 to 3x the length of such a field).

If you tell the average (US) person 1000 feet, they won't be able to envision it. But if you say "a little more than three football fields", they can visualize that.

The point of strange units of measure is just to make a quantity relatable.

[ProtoAES256]

Which football are we talking about again? That's a problem too.

[extraduder_ire]

An easy rule of thumb to remember this for temperature units; °F for "Freedom", °C for "Science".

[usefulcat]

Possibly a reference to this: https://en.wikipedia.org/wiki/Freedom_fries

[moffkalast]

> Chairman of the Committee on House Administration, Bob Ney, renamed the menu item in three Congressional cafeterias. The political renaming occurred in context of France's opposition to the proposed invasion of Iraq

"Refuse to go to war with us? We'll... remove you from our cafeteria menu! Take that!"

"... what do you mean they're actually Belgian?"

[jes5199]

that event is older than this website

[rainbowzootsuit]

There are two kinds of countries on earth:

Those that use the metric system. Those that landed a man on the Moon.

[defrost]

The country that landed men on the moon adopted the metric systems as the basis of its measures before most other countries and programmed its moon landing systems using metric.

The country is a metric country (see: Official definition of the US foot).

Its citizens, however, largely still roll coal measured by chains to the hogshead.

[rainbowzootsuit]

The previous moon thing is a joke and at least partially an explanation for "freedom units," which is a joking (I think) commentary about the citizenry's beliefs about "their freedoms," and somehow these freedoms translates to freedom from using the metric system when they roll coal along a couple furlongs of interstate (in a truck that contains only metric fasteners.)

[littlestymaar]

Yet the governmental agency responsible for the moon landing acknowledged that metric is a better system and adopted it…

[detourdog]

My problem with the metric scale is that when values are expressed in scientific notion they lose all reference to me.

I try to learn but the only thing I think I have retained is that if the number has a negative 6 its most likely a small number.

[vidarh]

So don't express them in scientific notation. That is entirely orthogonal to using SI units.

[VBprogrammer]

It always amuses me when I watch a machining video from someone using metric. I've just been exposed to too many US machinists and am much more familiar with "thous" and "tenths" but baffled by microns and 0.02mms.

[guappa]

Can you list a country that landed men on the moon who didn't have to hire German scientists to achieve that?

[Smoosh]

Liberia landed a man on the moon?

[hunglee2]

much appreciate ;-)

[ozim]

Is handling leftover brine accounted for in the calculations?

You know you cannot simply dump it back into ocean in one place. It is also a problem in Gibraltar or so to say they have it figured out but it costs them a lot of money.

[jillesvangurp]

Run a pipe out a few miles to where the ocean drops to a few hundred meters and the currents are strong and job done. This is not a technical challenge in any way, just a minor cost overhead. Pumps and pipes; that's all you need.

This is not the reason the US doesn't desalinate. It is actually actively making things worse in the places where it can still extract water from aquifers. Removing the water allows salt water to penetrate those thus destroying the local ecosystems. It's also speeding up the desertification of other areas.

Desalinating ocean water (done right of course) is part of the solution, not the problem.

Solutions like discussed in the article are more interesting for smaller/rural setups. Interesting but desalinating at industrial scale is a solved problem already. Can it be done cheaper. Probably and that would be nice. But it can be done economically right now. The largest challenges here are bureaucratic, not technical.

[detritus]

Given Gibraltar dumps all of its sewage straight into the Med untreated, I don't really think it much cares.

[haarts]

I was stumped when reading this. But it appears to be true!

https://www.yourgibraltartv.com/society/28113-tender-awarded...

[beagle3]

Gibraltars population is 32K, which makes this less crazy than it sounds at first.

[jack_riminton]

A shocking number of places in mainland UK do this too

[makomk]

I'm pretty sure there's nowhere in the mainland UK that just dumps all its raw sewage in the sea or in rivers - everywhere on the mainland was retrofitted with sewage treatment a while back. Now, those retrofits aren't perfect and sometimes raw sewage still overflows due to storms for example but we don't just routinely discharge all the sewage into the sea. There are still places in Spain, Ireland, and some other EU countries that haven't managed to build sewage treatment yet and actually do discharge all their raw sewage either into the sea or into rivers leading to it. (Yes, this is almost exactly the opposite of the narrative pushed by the British media.)

Gibraltar apparently doesn't have sewage treatment because they have some salt-water flush system for toilets due to fresh water historically being so expensive there and they seem to have had difficulty getting a treatment system that works with that.

[extraduder_ire]

Boil-water notices due to cryptosporidium and other nasties in drinking water are somewhat common in some places in Ireland. The difference in water quality and hardness between places that aren't very far apart is pretty striking.

[jack_riminton]

nah it's pretty bad https://www.independent.co.uk/travel/news-and-advice/uk-beac...

[concordDance]

This is probably fine for non-industrial wastewater tbh. Feces, urine and biodegradable toilet paper aren't putting anything in the ocean that isn't already there in vast quantities.

[detritus]

It's honestly not so wonderful an idea when you're downstream of it, which given the Med has a significant and continuous in-flow, means that people along the Costa del Sol swimming in the sea are probably having more than their fair allowance of Gibraltarian effluent.

[oldbbsnickname]

It may or may no longer be the case but Santa Cruz, CA beaches on the boardwalk received raw sewage during storms due to overflow comingling.

[beembeem]

This is the case across much of the US. Seattle dumped 100 million gallons of untreated storm & wastewater in 2022.

[bagels]

You can, but it has negative effects. Just like we can create landfills, we can choose to destroy a part of the ocean.

[ImHereToVote]

If we have a long pipe the pipe can mix the brine over the length of the pipe. This is what is done currently. No dead zones necessary.

[Retric]

> $.01 per 6.4 gallons

That’s not directly comparable to residential rates because you now need to pump that water up hill and through a distribution network to customers. Desalination occurs at sea level and getting that to anywhere but costal cities is even more expensive.

Further, 0.01 cents per 6.4 gallons is 500$ per acre foot which is horrifically excessive for agriculture where most water is used. Using it for Alfalfa would cost more than 10x what the crop is worth. Desalination is therefore still only viable in very niche areas without heavy subsidies.

[Veserv]

Or maybe the unsustainable depletion of groundwater for the purpose of growing alfalfa is only viable in very niche areas without heavy subsidies?

The number they are quoting is 0.41 $/m^3. Per capita water withdrawals (including agriculture) in the US were ~1200 m^3 in 2015 [1]. That means the cost per person to convert all residential, industrial, and agricultural to desalination is only ~480 $/(person * year). Or approximately 6/1000 of US GDP. Even if we assigned all of that cost to agriculture and food, all that would mean is that the average person's food budget would increase by ~480 $/year. That is sizeable, but not even slightest bit infeasible. If we really needed to we could just assign 3% of the US federal government budget to preventing death by starvation and thirst by achieving full water independence.

Desalinated water is only uneconomical in comparison to unsustainable groundwater depletion. On a absolute basis it is very affordable and would not constitute a material problem for the US or any other developed country.

[1] https://www.statista.com/statistics/263156/water-consumption...

[Retric]

Subsidies is arguable as groundwater isn’t necessarily useful unless you pump it out. How much to value that finite resource isn’t obvious but letting it run out is a self correcting problem.

Anyway your numbers aren’t even close. Water needs to reach people not simply exist. Groundwater depletion really isn’t a thing in the east cost, it’s mostly a thing west of the Mississippi and mostly at fairly high elevations.

To offset water withdrawals of people living 2km above sea level that 1200 m^3 of sea water would need 6480 kWh before consideration inefficiencies. For much of the Midwest you’re spending more on pumping than desalination, but you also need pipes etc.

[Veserv]

Oh geez, 6840 kWh. At 0.10 $/kWh that is ~700 $. Added onto the 480 $ that would increase the costs to nearly 8% of the US budget. If it takes a 8% increase in the government budget, I prefer dying of starvation and thirst, said nobody ever.

I am being a little flippant here. Transitioning to a desalinated water economy is a gigantic megaproject. I am not including the costs needed to add all the transport infrastructure, but we also do not need to convert over 100%. We only need desalination where we are consuming water in excess of water renewal rates. And if you need excess water you will need to move your business to where water resources are cheap. That or your business and people die of no water. I know what I prefer. Luckily, highly productive farmland which consumes the vast majority of the water is generally on flat, low elevation ground where transport costs will be low.

Desalination is a viable solution. Are there challenges? Sure. Can you do it without any sacrifices and without changing your lifestyle at all? Probably not. But if your alternative is insufficient freshwater resources desalination can solve that economically at scale at a modest cost and with relatively minor sacrifices.

[Retric]

Except this isn’t about drinking water its just agriculture and not even agriculture used inside the US.

Spending 8% of the US budget to subsidize exports would be lunacy. Ban Alpha exports from California largely solves the problem within the state as does a host of other possibilities like say charging a fee for using an aquifer.

Anyway it’s a self correcting problem, when farms can’t pump out water they will shut down reducing water use. The US is such a massive exporter that none of this will be noticed by US consumers.

[Veserv]

Then don’t do that. You are the one who brought up alfalfa, the classic example of a low value good being subsidized by unsustainable and flagrant water usage, as evidence that desalination is not viable.

I pointed out how even if we decided to support and subsidize the moronic use cases the US can still easily support a desalinated water economy if we had to.

In actuality, if we moved to bulk desalination we would see a reconfiguration of water usage to higher value usage since water would be immensely more expensive. However, despite being much more expensive, even if we massively overestimate water usage by including water wasteful export crops, desalination still ends up being viable including the usage that would almost certainly disappear if they did not get to defray their depletion externalities.

Massive overestimate comes out reasonable. Therefore correct estimate will also come out reasonable.

[concordDance]

> If it takes a 8% increase in the government budget, I prefer dying of starvation and thirst, said nobody ever

This seems like a false dichotomy.

[concordDance]

You're forgetting to take into account transport costs.

Want to pump that cubic meter of water 100 km inland and the energy cost alone will be over $1/m^3. Ignoring pumps, piping, maintenence, land purchasing, cabling, planning permission, etc etc.

[amluto]

> Further, 0.01 cents per 6.4 gallons is 500$ per acre foot which is horrifically excessive for agriculture where most water is used.

Which suggests that something is egregiously wrong with residential water pricing.

[brnt]

The price is not really for the water, which is too cheap to Meyer, but for the infrastructure, which is per liter transmitted a much higher fraction of the cost than industrial/agricultural users.

[amluto]

And yet most California utilities charge a connection fee and a per-unit-volume fee.

[bagels]

The water in the reservoir closest to me is at about 300 feet elevation and a couple miles from the ocean. Doesn't seem too bad.

[Retric]

Desalination plants are only that cheap at scale, if you’re in a costal city then raising water 300 feet isn’t a big deal. If you’re in a small community in a low density area or a large one 6,000 feet and hundreds of miles above sea level the math looks very different.

[bagels]

Many people live near the ocean. It doesn't have to solve every problem. Also I don't think many people are living hundreds of miles above sea level :)

[Retric]

The problem is it solves basically none of the issues.

Where people live isn’t where people consume aquifers faster than they are replenished. Across much of the east coast farmers don’t bother with irrigation because even the cost of pumping water from a well and delivering it to their fields isn’t worthwhile.

West of the Mississippi the amount of rainfall drops and therefore the need for water skyrockets. https://us-canad.com/rainfall-usa-map.html The difference between 150 inches per year of rainfall and less than 25 is huge.

At the same time the average altitude above sea level also increases. https://gisgeography.com/us-elevation-map/

So if you want to get water where it’s needed in the US. That’s mostly up hill and a long way from the sea.

PS: Coastal cities can always out bid farmers for water, or use some desalination but that’s a tiny fraction of the overall water usage.

[noduerme]

What we need is a coast-to-coast siphon.

[littlestymaar]

I know we've had decades of brainwashing trying to blame individuals for water and energy (ab)use, but residential water is almost never where the problem comes from when talking about freshwater: the problem comes from agriculture, and even at the rate you're talking about above it's not economical and we're still draining aquifers at an alarming rate.

[jonhohle]

Great, maybe California can give us back some of our Colorado River water rights.

[noduerme]

Not til you start wasting it on growing almonds and using the profits to bribe a few different legislatures.

[jshen]

That's not an accurate description of the history of this issue. There's a ton of crazy stuff in the actual history, no need to make stuff up.

[noduerme]

It was a snarky one-liner, not an exhaustive history of the Central California water wars.

[jpk]

Can you recommend some relevant reading?

[wiml]

_Cadillac Desert_ (Marc Reisner) is the classic, though it's quite old now.

I've heard people recommend _Dead Pool_ (James Powell) but I haven't read it.

[jshen]

I went to college in CA and took a couple classes on it. That was over 20 years ago so I don't remember what the books were.

[BMc2020]

I want to believe you, but your assertion fails the 'shout it from the rooftops' test. If it was true people would be shouting it from the rooftops.

[pjc50]

What? If you hear someone shouting something from the rooftops, more often than not it's a scam. Actual facts tend to speak very quietly.

[BMc2020]

Since this is news.y, I'll frame it in ST:TNG terms:

In one episode they discovered a way to use the transporter to become young again. You would think eternal youth would be a big deal, right? Nope, it was never mentioned again.

Eternal youth using a transporter would have been shouted from the rooftops.

[laurencerowe]

Would it taste as nice as Hetch Hetchy water though?

I swear that SF water started tasting worse after they started adding groundwater a few years ago:

https://www.nbcbayarea.com/news/local/san-francisco-new-sour...

[scottjg]

it was pretty noticeable to me. i don't think it's the groundwater specifically but they started treating the water with chlorine as part of the change, which you can definitely taste. i installed a filter under the sink and at least that fixed the problem for me... but it did make me reflect on what's in our water, in general.

[DoctorOetker]

I certainly agree about the great strides that were made, but there is much more room for improvement: while desalination has become cost effective for residential volumes, further improvements could enable cost effective desalination at even larger volumes for irrigation, and prevention of drought enabled wild fires, especially considering rising temperatures (air and soil).

[simonebrunozzi]

You seem to be in the know, so let me ask you: is current tech still in need of large areas to work effectively?

[selimthegrim]

Would having a nuclear plant nearby not help power/support this tech or the MIT one?

[rexreed]

The MIT one is completely passive only using solar energy, so no need for any power