17 ms·
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 pra
by joshe 3y ago
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-drying-world/?cf-view https://www.energymonitor.ai/tech/can-desalination-save-a-dr...
Residential rates:
https://sfpuc.org/accounts-services/water-power-sewer-rates/2023-rates-frequently-asked-questions https://sfpuc.org/accounts-services/water-power-sewer-rates/...
- selimthegrim 3y agoWould having a nuclear plant nearby not help power/support this tech or the MIT one?
- rexreed 3y agoThe MIT one is completely passive only using solar energy, so no need for any power
- depressedpanda 3y agoFor the international audience who don't use freedom units, 6.4 (US) gallons is ~24.2 liters.
- xhainingx 3y agoAnd $0.01 is ~€0.01
- avmich 3y agoFreedom units?
- usefulcat 3y agoPossibly a reference to this: https://en.wikipedia.org/wiki/Freedom_fries https://en.wikipedia.org/wiki/Freedom_fries
- jes5199 3y agothat event is older than this website
- moffkalast 3y ago> 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?"
- promiseofbeans 3y agoA 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 3y agoThe 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"...
- jrmg 3y ago
- hunglee2 3y agomuch appreciate ;-)
- jonhohle 3y agoGreat, maybe California can give us back some of our Colorado River water rights.
- noduerme 3y agoNot til you start wasting it on growing almonds and using the profits to bribe a few different legislatures.
- jshen 3y agoThat'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.
- jpk 3y agoCan you recommend some relevant reading?
- wiml 3y ago_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 3y agoI 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.
- noduerme 3y agoIt was a snarky one-liner, not an exhaustive history of the Central California water wars.
- laurencerowe 3y agoWould 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-source-of-water-groundwater-hetch-hetchy/1978906/ https://www.nbcbayarea.com/news/local/san-francisco-new-sour...
- scottjg 3y agoit 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 3y agoI 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).
- Retric 3y ago> $.01 per 6.4 gallons That’s not directly comparable to residential rates because you now need to pump that water up hill and through a distribution network to customers. Desalination occurs at sea level and getting that to anywhere but costal cities is even more expensive. Further, 0.01 cents per 6.4 gallons is 500$ 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.
- bagels 3y agoThe 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 3y agoDesalination 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 3y agoMany 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 3y agoThe 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 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/ 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.
- ozim 3y agoIs 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.
- bagels 3y agoYou can, but it has negative effects. Just like we can create landfills, we can choose to destroy a part of the ocean.
- ImHereToVote 3y agoIf 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.
- jillesvangurp 3y agoRun 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 3y agoGiven Gibraltar dumps all of its sewage straight into the Med untreated, I don't really think it much cares.
- 3y ago
- littlestymaar 3y agoI 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.
- simonebrunozzi 3y agoYou seem to be in the know, so let me ask you: is current tech still in need of large areas to work effectively?
- BMc2020 3y agoI 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 3y agoWhat? 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 3y agoSince 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.
- sandworm101 3y agoResidential 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 3y agoI 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_ 3y agoIt'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-desalination-reverse-desertification https://www.terraformation.com/blog/solar-powered-desalinati...
- AtlasBarfed 3y ago300,000 gallons, .01/6.4 gals so .01 * 300,000/6.4 is... $500. How often do they need the water?
- myfavoritetings 3y agoThat'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 3y agoCorn 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.