April 9, 2015

Water Woes – Can Desalination Plants End the California Water Crisis?

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Construction site of the Poseidon Desalination Plant in Carlsbad, California. Photo by Scott Varley/Media News Group

You’ve seen the headlines. You’ve heard the news about a California Water Crisis. It seems evident that we’re on a one way street to a water catastrophe. With reports saying there will be no more water in California by 2016, and the Governor implementing water restrictions for the first time in American history it does appear to be a dire situation. But then you hear the other facts about the situation – that residential use is only <15% of the states water usage, and that agriculture and oil production use over 80% of the water and are exempt from all restrictions. How can this happen?

The fact that corporations use of water is unrestricted seems like a crime to anyone with basic common sense. But unless you have the power and money to go up against Exxon and Nestle in court you’re not going to get very far. For the average person, this induces a feeling of helplessness. A feeling that no matter how much you do your part and conserve, it won’t really make a difference. It’s clear something has to give. That something just might be desalination plants.

Desalination plants have been around since the 60’s but have never realized their true potential. Extremely high costs of production, environmental concerns , and technology have made desal plants unfeasible in the past. But, hey it’s 2015! We’ve fixed that right? Well, kind of. The technology for desal plants have come along way in recent years. But first, let’s see how they work.

There are two kinds of Desalination processes, distillation and reverse osmosis. Distillation uses heat to boil the salt water, causing condensation to form after evaporation, just like the distillation process for making alcohol. The condensation is then collected for fresh water. This process uses way too much energy and is an outdated procedure. Reverse osmosis desalination uses incredible force (six times the pressure of a fire hose) to push salt water through a microscopic membrane. This membrane filters out unwanted salt particles at a molecular level, and even other minerals and pollutants, leaving pure fresh water as a result. This process use to require a ton of energy. But since the 80’s, the energy needed for reverse osmosis has been reduced by 75%!

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Unfortunately, there is always some bad news to go with the good. To get the salt water, desal plants have to suck millions of gallons of water a day through intake pipes. This results in sucking up tiny fish, larvae, and all types of microscopic life that is essential for the oceanic habitat. That’s not cool. Attempts have been made to stop this by putting screens on the pipes to minimize collecting marine life and large debris. But that’s not enough for the Coastal Commission and the Surfrider Foundation who want the affect on the marine habitat to be non-intrusive. Which is good. Then there is the problem of what to do with the super-salinated brine water left over after desalination. It must be diluted at a 5:1 ratio before releasing it into the sea by mixing it with more seawater or industrial wastewater. A heavy drought can change the importance of marine ecosystems to the public however, and fears of water rationing have put desal back on the menu for water solutions for the state.

Since the 70’s, California has dipped it’s toes in ocean desalination, but because of costs and environmental concerns it has remained off the table, until now. Carlsbad will be the guinea pig for desalination in California as the biggest desal plant in the entire Western Hemisphere, the Poseiden Desalination Plant, will go online in 2016. An additional 15 desal plant projects are proposed from LA to San Francisco, all of which await the fate of the Carlsbad plant. If it succeeds it will encourage others to try. If it fails, it will have a lasting effect.

It took over six years of of struggles before the Poseidon Group finally broke ground in Carlsbad in December 2012. It’s supporters endured many years of government permitting and won 14 lawsuits and appeals by environmentalist groups before starting construction. The 1$ Billion project has the entire desalination industry riding on it’s shoulders.

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Construction on the Poseidon Desalination Plant in Carlsbad. Photo by Scott Varley/Media News Group.
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Close-up view of the membranes that filter out the salt, other minerals, and microscopic impurities in the desal process. Photo by Scott Varley/Media News Group.
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The beach at Carlsbad near the Poseidon Desalination Plant. Photo by Scott Varley/Media News Group.

Although the environment is certainly a real concern, all conversations about desalination begin and end with cost. Typically, desalination water usually costs about $2000 per acre foot – about the amount of water two families of four uses in one year. That cost is double the price of building a new reservoir or recycling wastewater. It’s at least four times the cost of getting water from conservation methods like paying farmers to install drip irrigation or providing rebates for homeowners to get rid of lawns and install water-efficient toilets.

For the Carlsbad plant, two gallons of saltwater will be needed to produce one gallon of drinking water. To remove the salt the plant will use a crazy amount of energy – almost 38 megawatts, enough for 28,500 homes – to force 100 million gallons of seawater through filters. The San Diego County Water Authority has signed a 30-year contract to purchase 48,000 acre feet a year from the plant, and will pay from $2014 to $2257 per acre foot. It’s feasible for San Diego County because it’s large population of 3.1 million people (in the water authority zone) will help spread out the cost of the plant. It is proposed to be an additional $5-$7 on resident’s water bills to pay for the plant and the water it produces.

Of course, Santa Barbara residents have been through this exact same situation before. After a seven year drought in the late 80’s caused widespread panic, SB residents voted to spend $34 million on a desal plant. It opened in 1991 and provided water for four months before heavy El Nino rains ended the drought, and the city shut it down. When water from reservoirs and other sources become cheaper, the cost of desal becomes economically unfeasible. Ironically, in April 2014, Santa Barbara City Council members voted to spend $935,000 to hire an engineering firm, law firm, and lobbyist to try to restart the desal plant by 2016. By early June, the residents will vote to spend another $40 million to get the plant up and running.

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The Santa Barbara Desalination Plant. Photo by noozhawk.com
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The Santa Barbara Desalination Plant. Photo by noozhawk.com
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Intake pipes at the shore lead to the Santa Barbara Desalination Plant a few blocks inland. Photo by noozhawk.com

Despite the costs and eco-concerns, desalination is coming. Another Poseiden Plant project is slated for Huntington Beach, and another desal project is also scheduled for construction in Redondo beach. Cambria started to use their small emergency desal plant last November, and Monterey County officials have begun digging test wells in Marina as part of a plan for a $320 million desal plant. Water experts say that three desal plants will go up in SoCal over the next ten years, and another two in the bay area. At this time, it seems to be the only reasonable protection from long episodes of drought for the arid state of California.

Desalination data provided by Paul Rogers via Mercury News.

 

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