Eli5: why haven’t we started considering or implementing large scale desalinization in response to our water shortages?
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This blog post discusses how cheap solar should make it possible. From Casey Handmer:
https://caseyhandmer.wordpress.com/2022/11/20/we-need-more-water-than-rain-can-provide-refilling-rivers-with-desalination/
1. It’s still too expensive.
2. There’s not really a water shortage. Matter cannot be created or destroyed, only change forms.
1) money money money. Desal is very expensive for agriculture
2) we don’t have a water shortage, we have a water distribution problem
3) alfalfa
You must hear rather unique set of conditions, that is not all that common.
One, you need potable water shortage.
Then, you need plenty of sea water.
Lots of energy to remove the salt out
A strong economy to support your operation
Infrastructure to transport the products
Skilled workers to Maintain the plants
If you look at these requirements, you will see that they ynot all that common. Israel does large scale desalination, as it has abundance of energy, sea water, skilled workers and infrastructure but severe shortage of water.
I wonder why places like Australia, who get massive rainfall for a very short time don’t capture more of that rain water. I have no idea, but I read somewhere that 99% of the rain water just flows into the ocean.
The economics of desalinization make it a challenge. Plants are incredibly expensive to build, take a lot time to build so in the time it takes to design, approve, build and get on-line the drought may be long gone. And because of the costs to build, the amount of energy needed to run, the ongoing maintenance/replacement of filters, salt disposal, etc. factors to deal with the costs for the water it produces are much higher.
It’s very expensive, it costs about ~$4 per thousand gallons to produce (not counting initial building of the plant or upkeep costs), which is actually relatively pretty affordable for home use; drinking, showering etc.
However it’s extremely expensive for farms to use, corn for instance uses ~600,000 gallons per acre (significantly more in places that aren’t humid like California/Arizona/Nevada etc.), even if sold at cost, it would cost ~$2500 to grow an acre of corn.
In most places in the US that face drought the real issue isn’t that there isn’t enough water for household applications; drinking water, showering, or even wastefully watering lawns. A very large issue is people trying to grow crops where it shouldn’t make sense, trying to literally irrigate parts of a literal desert (like inner Southern California, Arizona, New Mexico) especially to grow really water intensive crops like almonds, pistachios, alfalfa, etc. is the main driving force that’s depleting water reservoirs.
Essentially, the way I understand it, in a lot of cases it would just be cheaper to pay them not to plant crops, and not bother building and maintaining a desalination plant.
TLDR; it’s very expensive, not too expensive for drinking or everyday use, but very expensive to try and use it to grow crops. And most of the issues of water shortages could be solved by implementing some system where less (or even no) crops (especially water intensive ones) are grown in deserts.
Man, Canada is shaping up as the next superpower. Almost as much oil as Saudi Arabia and 20% of the worlds fresh water. Not only that but naturally cleaner than bottled water because of leeching through the Canadian Shield.
Its really expensive for starters. Then you need a way to dispose of the salt, you can’t just put it back in the ocean. It uses alot of energy to desalinate water and then the maintenance issues on the plant…..
Energy. The energy costs of desalination far outpaces the value of what the fresh water produced would be used for.
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