Desalination in California

Wired has a story about the renewed interest and use of desalination in California, which is currently facing increased drought pressure with little sign of relief on the horizon:

But now, with snowpacks at zero percent and reservoirs looking more like puddles, engineers in San Diego are preparing to hook up a new $1 billion desalinization plant that will provide enough water for 300,000 thirsty people each day.

Desalination, of course, has been intensively used for quite sometime in other places. The new plant (first proposed in 1998) comes amidst a broad renewal of interest in widening California’s water supply :

Santa Barbara’s mothballed plant will start running again after sitting idle for 23 years. Cambria, Calif., opened an emergency $9.5 million desal plant in November 2014, while Monterey County approved “atmospheric water generators” (just like Luke’s uncle ran on Tatooine) to supply water for some businesses and industrial parks.

The article also has the mandatory statement about heightened financial costs of desalination. Their ballpark numbers are a 1:1 rate of cost growth (i.e. a 7% shift to desal would raise the cost of supply about 7%) so California’s water bill is going to go up. They don’t talk about the growth in requirements on other infrastructure, but this is understood. The developers plan to mitigate some of the discharge problems by using the fact that warm water is a waste product of power generation:

The developers are building the plant next to a gas-fired power plant in Carlsbad, about 35 miles north of San Diego. That way it can take use some of the power station’s coolant water to dilute the salty brine discharge.

We’re likely to see more integration of infrastructure pieces like this.

The article closes with a brief mention of the work by a microfluidics research group at MIT to develop single-layer graphene membranes.