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Comment by krisroadruck | Hacker News Reader

I simply do not understand california's water shortage problem. They are by a frickin ocean. It's sunny nearly all year round. Solar powered or wave powered desalination is a fairly straight forward solution to this problem.

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Why desalination isn't the answer... http://blogs.kqed.org/science/audio/why-isnt-desalination-th...

I was literally going to post the exact same article. Up until I read this a few days ago, I would have jumped into a debate with "desalination! just do it!" -- turns out it's much more complicated than that.

Why aren't they simply boiling the water, nuclear powered? That article says membrane desal leaves half the water extra salty, is that right? Does boiling it leave that much? I'd imagine there'd just be a concentrated, mostly-solid byproduct.

I'm probably wrong else everyone would already be doing this. OTOH, many people and places seem to be going against nuclear power, so perhaps it isn't just a technical issue. At any rate, that article just left more questions than answers.

Is nuclear cheaper per joule than other energy on the grid?

They'd essentially be running a nuclear powerplant, which wouldn't turn out any resellable power, just water.

tl;dr: Desal is too energy intensive and expensive to be feasible while other conservation options haven't been tried yet. Also, massive potential environmental impact for water intake and brine output.

I find it odd that it's too expensive. It's cheaper than the price of water in e.g. Finland and many European countries, yet I've never heard anyone complain about the price water.

http://en.wikipedia.org/wiki/Desalination#Economics http://www.vercon.fi/fi/tietoa-vedenkulutuksesta/veden-hinta...

I was going to say. Look at the numbers in the article. $25,000 per month for 1200 homes. That's $20.83 per month. I'm sure costs down down with scale.

Not that much different than what I'm paying for municipal water.

Because the real problem is inland, so as well as desalinating the water (which is somewhat easier said than done, though I agree in principle), it would have to be pumped inland and mostly uphill for millions of miles.Our state water infrastructure is ancient, we just last year secured passage of a $9m bond to overhaul it, despite the vociferous objections of the farm lobby.

mostly uphill for millions of miles.

Not quite that far. San Francisco to New York is less than 3K miles. Maybe tens to hundreds of miles.

Hehe, well spotted. Hundreds of miles and of course I should have said a '$9 billion water bond' too.

Of course, one day headlines may read 'California to import water from Moon,' and I will be hailed as a great visionary. You read it here first!

While a pipeline network may not be millions of miles from one end to another, it's certainly possible that the sum of the lengths of all the pipes in a tree-like network may be much greater than the length of the network's longest path.

If they build desalinization plants wouldn't they just pipe the water into existing infrastructure? At worst that would mean piping it over to the other side of the state where they usually get their water from snow pack and what not, no need to completely duplicate their water distribution system just because they have a new source of water.

Desal plants are at sea level on the coast. Most headwaters are thousands of feet above sea level and hundreds of miles inland.

Water infrastructure is almost entirely gravity fed. Even if we could justify the immense energy usage, we can't drive existing pipes and canals in reverse.

Desalination is incredibly expensive. At this point, they aren't completely out of water, as the crisis continues desalination will become more viable (expensive or not, people need water to survive).

Desalination is expensive because of the cost of power, but what is being proposed is not just "we should desalinate", but is "Why don't we make better use of the power opportunities," such as a desalination plant with solar panels and/or generators for waves/tides. We could offset the electrical cost of desalination if the plants could help generate their own power. Why not pass water through turbines before desalination? There are tons of opportunities for refining the process, and it's just the initial cost that's large. Over time, the plant will pay for itself and if ever optimized, could actually provide power back to the grid.

Solar power is more expensive than fossil fuel power. The solution to "desalinization is too expensive" is not to say, "But what if we used a more expensive form of power to do the desalinization?"

Maybe for base load, but desalination can run intermittently during sunlit hours only. You only have to stay ahead on average..

The solution to "desalination is too expensive" is ALSO not to only use your desalination facility some of the time, and also when the price of energy is highest.

Solar is cheaper per watt in many parts of the world, assuming you don't care when you get those watts. You can build more solar capacity than what's needed during daylight hours in which case you can't sell the energy due to there being too much of it, so high price of energy becomes irrelevant.

(or: you can't build a large number of solar power plants without affecting the market price of electricity)

Ah, so now your plan to reduce the cost of desalinization is to build so many solar power plants that you literally have more energy than you can possibly sell during the highest demand parts of the day. Well, that sounds like a good cost reduction technique.

Oh, wait. No it doesn't.

Are we talking about water or costs?

> Desalination is expensive because of the cost of power, but what is being proposed is not just "we should desalinate", but is "Why don't we make better use of the power opportunities," such as a desalination plant with solar panels and/or generators for waves/tides.

The capital cost of that is the cost of the generators + the cost of the desalination plants, and the desalination still probably isn't, even with the drought, the most valuable use of the power once you've built the generators.

> We could offset the electrical cost of desalination if the plants could help generate their own power.

We couldn't offset the opportunity cost of using the power for desalination rather than other uses that way, obviously.

> Over time, the plant will pay for itself

If its a permanent drought, maybe. Otherwise, that's doubtful. If the water isn't worth the electricity now, its an operating loss on top of the capital costs.

> Why not pass water through turbines before desalination?

You spend a ton of energy pumping the seawater up to pressure, then you pass it through a turbine? Why on earth would you do that?

According to Wikipedia it's really cheap: http://en.wikipedia.org/wiki/Desalination#Economics

Rainwater is cheaper. IF you look at how much residential users pay, then yeah you see that desalinization would not break the bank, but most water is for farms and they get it by the acre-foot.

These plants seem to be self-sustaining (they even create extra energy) and can provide potable water from the oceans:

http://cleantechnica.com/2015/03/15/first-kind-wave-energy-f...

It's technically possible, but not at the right prices. California has been supplying water to agriculture at below market prices.

> California has been supplying water to agriculture at below market prices.

Is that actually "supplying", or is it that farms have been located at rivers precisely for the reason that they have access to water there, and water rights are part of property rights?

(Honest question, I don't know California system.)

I'm not sure either but there is an man made aqueduct that stretches form north to south.

Here's an article that goes into the complications and controversies of desalination in California. http://www.mercurynews.com/science/ci_25859513/nations-large...

The reality of desalination is that apart from Karlsbad where they are already building one, there are very few places you could build a desalination plant and associated power plant without someone (rich person or environmental group) getting lawyered up.

Then you have the problem of getting the water from the coast to the Central Valley. Given that it's going to take 20 years to build 400 miles of train track I don't hold much hope getting pipelines of a similar distance getting built in under 10 years.

People have had water for a fairly low price that nobody really cares about it. Now they have to care, but it's not the end of the world (yet). Solar/wave powered desalinization will look a lot more interesting when they hit bottom. Unfortunately nobody will move before it reaaaaally hurts them.

Note that California's electricity "market" is anything but that, and a bizarre regulatory mess. You may remember Enron being bad many years ago, but they exploited the regulations. The net result is amongst the most expensive electricity in the country. The electricity companies aren't even allowed to set their own rates. http://www.sandiegoreader.com/news/2014/nov/19/citylights1-c...

You should listen to this podcast about desalinization. Towards the third part of the podcast they talk about the problems with desalinization and why it isn't always the solution. I just listened to it yesterday, very interesting!

http://www.stuffyoushouldknow.com/podcasts/how-desalination-...

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