Along San Diego’s coast, two major power plants were built on the coast for a reason. The Carlsbad and (now defunct) Chula Vista power plants needed water to cool their inner workings. And they needed a lot of it. Millions of gallons a day.

Water went in cool, came out warm. Day in, day out.

In Carlsbad, developers of a private desalination plant want to use that existing seawater intake to get water for their proposed facility. It saves millions to use an existing pipe rather than to build your own.

But at the same time, California is phasing out those types of power plants. Technology has advanced. Power plants no longer need water to keep their insides cool (technically known as once-through cooling). They can use air. That’s good news for fish and marine life, which get sucked in and chewed up when power plants pull all that water in (technically called impingement and entrainment).

That’s the context for a comment worth sharing on my story about desalination efforts under study in Rosarito Beach. They’d use existing intakes, but unlike California, Mexico isn’t shifting away from once-through cooling.

Marco Gonzalez, an Encinitas environmental attorney, noted that difference in a comment on my story:

[Y]ou missed the most relevant difference between what would occur at this power plant versus co-located proposals in California — our statewide “once through cooling” policy. One of the reasons it makes no sense to allow projects like that in Carlsbad to draft off of water coming through the Encina power plant is because that plant (and all other OTC plants) will go away in the foreseeable future due to mandates to move toward dry cooling. When those plants repower, their highly destructive fish kills will cease (unless there are desal plants attached to them). If in fact there is no similar policy at play in Mexico (and there isn’t), then co-location might actualy make some sense. We’ve said all along that the driving force against coastal desalination in California is the continuation of impacts from impingement and entrainment. If those impacts are going to occur anyway, then our argument doesn’t…water. Or at least, not as much…

That desalination in Mexico might make sense is an interesting argument from Gonzalez, who’s led the legal fight against the Carlsbad plant. When I spoke to him while researching my story, he made this point about desalination in Mexico:

It’s bad public policy. If you can’t build it here, why are you trying to build it there?

Gonzalez may have answered his own question.

Please contact Rob Davis directly at or 619.325.0529 and follow him on Twitter:

Rob Davis

Rob Davis was formerly a senior reporter for Voice of San Diego.

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