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Comment by barathr | Hacker News Reader

While this is a nice project for emergency and remote uses, what we really need re: desalination in places like California (and other variable / dry climates) is large-scale desalination tied to opportunity power (such as curtailed grid power).

With each passing year there's going to be more and more solar on the grid, and it's going to be hard to soak up that power during the daytime peak. Desalination matches the solar supply curve perfectly: there's more water demand during the day, and there's also more water demand during the summer when there's also more sun. It's the ultimate dispatchable load.

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Do we really need expensive desalination in California? Domestic water use only accounts for 20% of demand and desalination seems unlikely to ever be cheap enough for agricultural use (the remaining 80%.)

Other than a few coastal places like Marin and Sonoma that aren't on the state water project I think the answer is no. The resulting water will be too expensive. It would be cheaper to pay farmers to stop growing inefficient and largely unnecessary crops (pasture grass, alfalfa) or to move to more efficient drip irrigation. As you said, the domestic use is so low and ag users wouldn't pay for desalination when there is actually a fairly sizable (although possibly dwindling) source of water available.

Most coastal communities in southern California don't even bother to reservoir off their water during rain events, instead letting it drain into the ocean. One major exception being Santa Monica which only uses 40% of it's water from up north unlike other communities which are 100% reliant on it.

Back of the envelope math suggests that based on average rainfall amounts per year a place like Ventura county could be entirely self-sufficient without any desalination plants.

Agriculture can also switch to drip feeding water instead of spraying which cuts usage by 90% without lowering yields.

There's a lot that can be done. We just need the political will to make it happen.

Having extra reservoirs can also support more natural vegetation and potentially actually create conditions for more rainfall further from the coast.

You could get a lot of mileage out of just cutting out that billionaire's almond groves. Or make him pay for his water; at last report, he was stealing it with a pipe stuck through the side of a canal dike.

I'm curious what your favorite alternative to alfalfa might be.

I don't like alfalfa, it tastes bad and is very fibrous. I prefer arugula.

Fewer livestock.

Nice username :)

> Do we really need expensive desalination in California?

It’s a good question, and it’s been discussed quite often in recent media sources for the past two weeks due to the rejection of the proposed Poseidon plant in Huntington Beach.

The honest truth is you could probably argue for both sides. Realistically, it’s cheaper and less environmentally harmful to promote non-desal measures, but not as easy to see quicker and observable benefits. The problem with the latest proposal was that it had a lot of problems, and the company behind it has a paper trail of small scale disasters in its wake (see the failure of the Tampa Bay facility, for example).

I personally believe that this is the kind of project that could benefit from a closer partnership between the government and private industry. From what I can tell, the technology is mature and feasible, but every time someone tries to design and implement it in the states, they seem to drop the ball.

I would be curious to see the record of success of other large scale projects outside the US. I’ve heard about the benefits and risks of the plants in the Middle East and elsewhere, but I don’t know the details.

Id imagine a lot of the other desal plants (esp. those in Saudi Arabia) are less than obligated to admit to their resource usage and waste products. Apparently desal is very energy intensive. OP pointed out using solar but I would like an equivalent of how many 400W solar panels does it take to make 1 gallon desal water.

No idea, but AMTA reports 2.5 to 3.5 kwh/ m3 (10-13 kwh/kgal). They write: "Based on nationwide data from the Energy Information Administration, a typical refrigerator average annual energy usage is 1,400-1,500 kwh. Using the average US water use per household of 100,000 gallons per year, the energy requirement for supplying desalinated water to a house in the US will be less than an old refrigerator, but the same as a newer, more efficient refrigerator power use."

My small desalination rig uses about 1200 watts and makes 30 gallons per hour. It cost me $3500. So it’s doable with 3 panels for this 2 person household.

I’d imagine a plant would benefit from economies of scale. Though these benefits could get eaten up by cost overruns. Frankly, it seems the hurdle in California is working through the people issues/concerns than technical problems.

It’ll be interesting to see the stats on this new desal technique when they have a product for sale.

1200 W for 30 gal/h works out to 10.6 Wh/L (or 38 kJ/L).

True, though there's a question of whether there will be demand to keep up those ag uses as water becomes more scarce generally (I could see it going either way).

Electricity is something like half of desalination's operational cost, and we're already in a situation where the price on the grid goes negative (or is curtailed) during solar peaks and more and more solar is being added to the grid each year. So power for desalination is going to be near free in the coming years. (Whereas for other less flexible loads, electricity isn't likely to get cheaper quickly, since we have to either have storage or use gas plants.)

The last desal plan in SoCal just got shot down ... the plant in my area was voted down not long ago as well. There needs to be a bit more suffering and research before most are going to agree to the clear negative aspects ... I love fishing and a clean Bay too. We, however, are gonna run out of water. By that time its going to be an entire California event in which the plants arent supplying just the local water districts but most of the state. At that point were just gonna eminent domain Fort Ord and build an effluent pipe half way to Kauai.

I don't know if we're truly going to run out of water or not, but there are many measures it would make sense to take before building desalination plants, such as recycling water and more efficient agricultural water use.

Agricultural use accounts for the overwhelming majority of water use in CA. I doubt Bay Area and LA residential faucets will go dry before water use is reformed. The rural areas are massively out-voted by the urban centers.

Not everything is reformable via public vote. Property rights and constitutional rights are largely on the side of the agricultural users.

Faucets will never go dry because human drinking water is a minuscule use. Some sprinklers and pools may go dry in times of drought

Property rights are governed by laws. Legislatures can change laws.

We have a desal plant in Santa Barbara: https://www.santabarbaraca.gov/gov/depts/pw/resources/system...

> Do we really need expensive desalination in California? Domestic water use only accounts for 20% of demand and desalination seems unlikely to ever be cheap enough for agricultural use (the remaining 80%.)

If you like to eat, yes, you do. I still cannot fathom what distorted minds most transplants possess: California was and is an Ag state, it;s a fundamental part of it's culture it also feeds most of the US with its produce/fruit and exports it's surplus all around the World in surplus commodities.

Yes, stricter water preserving techniques are required for Ag, this recent budget surplus should go towards that as well as desalination to replenish aquifers and reservoirs/quarries after decades of an unsustainable population growth. This recent COVID exodus needs to go on for decades for the population to just return to the norms of the 70-80s.

You guys that write this kind of misinformed responses are so delusional, you cannot eat apps or drink code when you're hungry: and I can assure you will be the first to break when you haven't been fed for a few days or have to ration food/water since you've been accustomed to a lifestyle that simply doesn't reflect reality. And I highly doubt you can do any level of manual labour in order to feed yourself, either.

Get real, water conservation methods all around needs to be enforced BY EVERYONE! AG is guilty of exploiting loopholes when CA water laws were written to serve prospectors, and they should be taxed for over-useage and incentivize them with grants to utilize drip irrigation systems etc... but if you really want to solve this issue, which most of you won't agree to, is remove Farm subsidies: this will force farmers to cut down on these practices to make alfalfa or soy in the Central Valley for export to China that is only profitable because the State subsidies this horrific business model, it in turn will make food get even more expensive, which if you look at it in terms of net income is the historical norm: ~15% of total net income [0].

Food security is a matter of national security for a reason, it's used as a reliable weapon in warfare and has been a reason why most of humanity has gone to war in the first place, and if you like to keep civilization operating it's absolutely critical.

0: https://www.thevintagenews.com/2020/05/07/grocery-store-pric...

"you cannot eat apps or drink code when you're hungry: and I can assure you will be the first to break when you haven't been fed for a few days or have to ration food/water since you've been accustomed to a lifestyle that simply doesn't reflect reality. And I highly doubt you can do any level of manual labour in order to feed yourself, either."

This is cathartic and fun to read - and it equally applies to bankers, and other highly paid wankers.

Our economy as a whole underpays and inderinvests in the foundamental things that allow advanced society to exist - as the whole climate crisis demobstrates.

The Midwest is capable of growing all the alfalfa we need. Ending alfalfa alone would solve the water shortage for at least a decade. And it's mostly just exported to China.

I eat apps when I’m hungry

> I eat apps when I’m hungry

Kek, as a former cook I should have structured those 2 metaphors differently, but yeah... ok yeah you got me on the play on words. Well played.

Yeah! California could fix the water issue by restricting agricultural use water. That way, California could finally kill off it's agricultural production. This will ensure farmers will move to other states and turn to the plentiful supply of hard drugs. This seems exactly what California will do. You would think California politicians might make a good decision -- EVEN by mistake once and while -- but NO. How is that train from LA going?

https://www.reuters.com/world/us/california-staff-report-rec...

This is just "But think of the farmers!!!".

Across the US, farmers are not poor. By dint of being landowners, they are in fact some of the richest people around. See, e.g., this article: https://www.theatlantic.com/ideas/archive/2021/09/trump-amer... or this one: https://www.nytimes.com/2022/05/14/opinion/sunday/rich-happi....

Exactly. They are loaded, especially from farm subsidies. On paper they are super rich. We should cut off their water, force them to pay taxes on their still operating farms, and sprinkle salt all over the land. California should shoot down the water desalination projects (like it has for 20 years) and punish it's citizenry.

"This will ensure farmers will move to other states"

This does not even make sence - Are they going to sell their farmland? To whom, other farmers? Are those other farnera not going to farm the famrland?

I've posted about this on here before but the remaining 89% actually isn't just agriculture, though that is a Californians favorite scarecrow.

https://en.wikipedia.org/wiki/Water_in_California#Uses_of_wa...

> Water use in California is divided into approximately 51% for environmental uses, 39% agricultural use and 11% urban uses, though that varies considerably between regions and between wet and dry years.

"Environmental" uses seems to mean they're just allowing the water to run naturally to maintain the environment. (This is the source Wikipedia cites: https://www.ppic.org/publication/water-use-in-california/). It's funny that they call that a use of water in California. If you remove that, then yes, agriculture uses 80% of the water.

Actually, it's more convoluted than that:

    Water that naturally flows into the state’s “wild and scenic” rivers, which are not connected to the state’s water system and can’t be under state and federal protections
    Water required for maintaining fish and wildlife habitat within streams
    Water that supports wetlands within wildlife preserves
    Water needed to maintain water quality for agricultural and urban use

https://www.sandiegouniontribune.com/news/drought/sdut-sacra...

I'm unable to tell whether that's a tally for untapped water or if it's really meant to account for something meaningful.

The CFB does say that ag accounts for 80% of "human use".

I tried reading the wiki article and couldn't find an answer. Could someone explain to me what "environmental uses" is?

https://www.newyorker.com/news/dispatch/the-biggest-potentia...

..also, water storage is fairly straightforward, so the water usage peak doesn't have to exactly track with the daily solar power production peak.

depending on how you build the storage, you could also use the excess water for power, no? Some sort of gravity battery setup.

Yep, it’s called pumped hydro: https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricit...

I think it’s very promising/exciting as a method of smoothing out the demand curves of the electric grid. Plus, it’s fairly straightforward to modify existing dams/hydro infrastructure to have this capacity.

Since some dams are already used as water reservoirs for drinking/agriculture, this could be quite viable if the desalination can be done cheaply and efficiently at scale (not sure if this is even possible on the scales required for this idea to make sense, though).

Pumped hydro has been extremely effective in Australia since the mid 1960's. There's currently a project to extend the capacity of the Snowy Hydro scheme to soak up this extra transient renewable capacity.

https://www.snowyhydro.com.au/generation/the-snowy-scheme/

That's cool -- I didn't know that! Imo, the more effective and cheaply we can store energy and smooth out supply/demand curves, the more attractive solar and wind becomes.

Perhaps one way of encouraging a "greener" grid is to first encourage the development of cheap energy storage solutions, and then letting the market figure out the best way to utilize such storage (rather than the other way around). Might lead to more efficient/creative green energy solutions.

got get it up there ... places like Cali dont have a lot of rain that places itself up there and runoff is running out.

That's the point you can pump the water higher using excess renewable energy (in the event we get past 100% peak renewable power) to be used later when there's a deficiency. It's a fairly efficient method of time-shifting renewables without having to mine huge piles of lithium.

Pumped hydro if geography permits is very good storage method. Efficiency is not horrible, it is simple to ramp up and down. Technology is extremely mature. It scales pretty well. And as final bonus in some cases it can contribute to grid stability.

Yeah the biggest downside is the ecological impact of the flooding involved in creating a new hydro source. They could maybe look at retrofitting it onto an existing hydroelectric dam so it's not flooding a new area.

A hydro power reservoir doesn't need a watershed, so can have overwhelmingly less ecological impact.

It still needs volume to flood to hold the water though and unless we're building up artificially the cheap way to do that is to build fairly wide. All that area is habitat and covering it has an impact. In the end it's probably well worth it so long as we're not destroying rare habitats to do it but it is still destruction that has to be considered and weighed.

Pumping desalinated water up to Sierra Nevada reservoirs would take a hell of a lot of pipe. We use canals and rely on gravity to move water, today.

I wonder whether the most efficient way to get water to the Sierra Nevada reservoirs would be to pump ocean water onto the desert, and let evaporation take it from there. Siphoning from the ocean into Death Valley, you wouldn't even need to pump it.

I'm going to assume you mean "up there" as in northern cali -- if we could get some clean hydrogen/electric transport trucking it shouldn't be impossible to move it around either!

Nuclear power to the rescue (again! Lol) use excess heat from nuclear power generation and the water that gets steamed anyways for cooling and desalinate it. The brine problem can be solved by not desalinating endlessly but using desalination to create lakes and dump the brine in the desert where nuke waste is buried.

Mixing corrosive saline and nuclear waste storage facilities is probably not the best idea.

Nuclear power is, as always, overwhelmingly more espensive than the alternative, solar. We have a great deal of desert in California, with plenty of sunshine, and evaporating only when the sun is out is fine.

You wouldn't even need enclosed evaporation containers; let the wind carry the moisture to the mountains, raining into existing reservoirs.

One of the big challenges: convincing people to drink water that was desalinated at a nuclear power plant.

Who said drinking. Use it to water all almond trees and golf grass, that takes up much more than drinking water. Or livestock too.

Where you see a challenge, I see an incredible marketing opportunity. People are buying water with a brand name of “Liquid Death”.

We already have a pool of brine in the desert.

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