San Diego and Monterey are already exploring desalination options for water supply. This article discusses a smaller plant in Southern California. It would cost $136 million (if it came in on budget!) and provide water at a cost of $1,287 per acre foot. (Residential users pay about $800-1,200/AF now.) But wait, who's going to pay the $136 million?
Bottom Line: Like people who pay $22,000 for a Prius to save $10 on a fill-up, these guys have to look at fixed and variable costs (compare true cost to own to Yaris here). Not such a hot idea now, is it?
07 May 2008
More Desalination
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4 comments:
What about desal plants to treat agricultural drain water? The gap (too confusing here to use the term "delta") is much smaller: you are starting with water much less salty than sea water, and ending with a product sufficiently pure to discharge into a public waterway, or to irrigate with; not to drink. Even with present crop prices, this is still not an economic burden that agricultural users could support alone. However, if the plants were paid for and operated by urban agencies, who in return would get to use some fresh water now delivered to agriculture, the scheme might still work.
Philip,
You are absolutely right. (I swear that I have written that before but perhaps not.) Las Vegas uses brackish groundwater in all those outdoor water fountains and lakes.
I *do* write here that ocean desal water is "preferred" by many places because it avoids the problem of property rights -- right now, anyone with a straw can suck as much ocean water as they want. In your scenario, agreement among farmers, cities and downstream people is necessary if runoff is to be diverted into a desal plant. (Just look at the mess when IID wanted to conserve runoff -- they were sued for reducing inflows to the Salton Sea!)
The interesting cusp we may be approaching now is that, like it or not, appropriators of water are now seen as having a possessory interest in their discharges. If that interest can be translated into something valuable(as in being able to convert an environmental liability into a salable asset) we might be on the path to something helpful, instead of perpetual whiny wars.
I both use and create agricultural discharge (as have irrigating farmers from time immemorial). Like many, I'm just looking to market forces to come up with better, faster solutions than police forces can. What I like about desalinating ag drain water, while paying for it with reallocating existing developed water, is that it solves two important problems at the same time, at a very low cost. Mitigation of drainage treatment costs, even generating net profits from the provision of this water for treatment, might offset some of the cost of reduced irrigation supplies. I claim no authorship of this scheme, many have suggested it in the past.
And yes, the Salton Sea fiasco is just laughable. Here we have a "sea" that is simply an accident of poor engineering, which now must be preserved at great cost. It is a handsome and moderately valuable habitat, but it's no more natural than Britney's boobs.
In Califonria, discharged water is subject to appropriation. For example, the base flows of the Santa Ana River (which was until just recently a fully-appropriated river, closed to further appropriation) include the discharges of all the cities in Riverside and San Bernardino.
Diverting to a new use water that had previously been discharged to a stream requires the filing of a Change Petition with the California State Water Resources Control Board, and processing that petition.
Desalinating ag water still leaves the problem of disposing of the brine stream. It's a lot easier for a desal plant on the ocean to build a discharge point than it would be for, say, the farmers on the west side of the Central Valley.
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