Diamond-Cut Life

This is Part 1 of a two-part story on desalination, the energy-intensive treatment of ocean water to render it drinkable. This post gives general information on desalination, and Part II will evaluate its merits, particularly in regard to quality of life and global warming.

If you live in the U.S. and you have deliberately drunk water that was recently in the ocean, you are a rarity. At least so far.

Many, especially in the arid and increasingly drought-ridden West, are working hard to change that. The oceans contain 94% of the planet’s water, and unlike shrinking glaciers, rivers, and subterranean aquifers, this water supply isn’t being threatened by global warming or expanding human populations. (When we drink untreated ocean water, our bodies expel more water in urine than we’ve ingested, in order to get rid of the toxic level of salt.)

I was surprised to learn that 13,000 desal plants already exist in the world, particularly in desert regions like the Middle East and Australia that have very little natural freshwater relative to human population. 2,100 of those desal plants are in the U.S., but they are mostly small facilities treating brackish groundwater rather than ocean water.

Currently desalination generates less than one half of one percent of U.S. water supplies. The biggest proponents of the many desal plants under negotiation or active construction tend to be politicians, developers and water utilities in the seven states using the shrinking Colorado River for their growing water needs. A summary of the challenges they face:

• The desal process requires enormous amounts of energy
• Most energy production produces the carbon emissions that create global warming
• Desal plants are unusually expensive and prone to cost overruns
• They’ve been termed the most complex infrastructure in the world
• Ocean water gets pumped through 8,000 membranes in the reverse osmosis process
• “An operations and management nightmare” is one expert’s term for desal plants
• Desal plants kill millions of fish and fish larvae

photo courtesy of William Dalton

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• Making The Ocean Drinkable, Part II
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