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Solar Desalination Could be a Game Changer for California Farms

Solar Desalination Could be a Game Changer for California Farms thumbnail


Let’s be clear from the outset: I’m no fan of conventional desalination.
The idea of using climate-altering fossil fuels to drive an energy-intensive de-salting process that threatens coastal environments in order to produce drinking water that, in most cases, could be secured more cheaply through conservation and efficiency improvements, simply fails to pass the bar of economically sensible, environmentally sound solutions to our water problems.
But now desalination of a very different stripe is under way – not by the sea, but in California’s drought-stricken Central Valley farming region. The project is turning salty, contaminated agricultural drainage into fresh water that can be re-used to irrigate crops.
Powered not by fossil fuels, but by the sun, the technology has the potential to shift the way water is used and managed in parts of the west, where agriculture accounts for 70-80 percent of water use.
Developed by a San Francisco-based company called WaterFX, the solar desalination unit has been piloted in the Panoche Water District in Fresno County. Farmers in the area grow a wide variety of crops, including almonds, asparagus, tomatoes, pistachios, cotton, alfalfa and wheat.
The district is located on the valley’s west side, where farm drainage contains not only high levels of salt, but also selenium, a naturally occurring element that is essential in trace amounts but poisonous at high concentrations.
In the Central Valley and elsewhere in the western United States, irrigation has washed considerable quantities of salt, selenium and other contaminants out of the soil and into drainage water, which has polluted rivers and wetlands, and harmed birds and wildlife.
WaterFX’s “Aqua4” system offers a way of addressing both these critical contamination problems and mounting water shortages.
The technology uses parabolic mirrors to concentrate the sun’s energy, heating a tube that then distills fresh water out of the salty drainage. It’s an age-old process made far more efficient with modern technology. The system can produce 200 acre-feet (65 million gallons) of water per acre of solar collection area, making it, according to WaterFX, the most efficient solar desalination system available.
In addition to the solar collection, absorption and distillation equipment, the system includes a unit to store the solar thermal energy it produces, ensuring round-the-clock operation. It can also reclaim the metals and salts left behind from the distillation process.
During the drought, farmers in the Panoche and other Central Valley irrigation districts have faced cutbacks of 80 percent or more in their water deliveries from the dams and canals operated by the federal Bureau of Reclamation. The possibility of treating and reusing the water they do get to sustain more crop production has obvious appeal. And the districts are under the gun to further curtail the harmful pollution draining off their fields into the San Joaquin River.
The Panoche District has already made moves toward more sustainable production, including the institution of a tiered pricing schedule, where farmers pay more per acre-foot the more water they use. The majority of farms now use highly efficient irrigation systems, mostly drip and micro-sprinklers, to get more crop per drop.
With the ability to treat and reuse their water, farmers can stretch their limited supplies even further.  At a minimum, that could afford an effective hedge against drought.


The modular solar thermal technology converts previously unusable farm drainage into a new, local source of clean water. Photo courtesy of WaterFX.
The modular solar thermal technology converts previously unusable farm drainage into a new, local source of clean water. Photo courtesy of WaterFX.

But WaterFX has bigger plans.
“Our long term goal is to chart a new course towards water independence and reduce the need to import water from finite natural sources,” says Aaron Mandell, co-founder of WaterFX.
Success will depend, of course, on cost and scalability.
Aqua4 is both modular and moveable. A single module occupies 6,500 square feet and can treat 65,000 gallons per day. That basic formula – 10 gallons per square foot per day – is scalable to any size, says Mandell.
The Panoche District will continue piloting and assessing the solar desalination process over the coming years to determine if it is suitable for “scaling up,” district general manager Dennis Falaschi told the publication Ag Alert last month.
Meanwhile, WaterFX is actively moving to scale up. Through a project dubbed HydroRevolution, the company is organizing a community-based fundraising campaign to expand on its work with Panoche and build the Central Valley’s first commercial solar desalination plant.
The goal is to take drainage from 7,000 farm acres in Panoche and other neighboring districts and churn out 5,000 acre-feet (1.6 billion gallons) of clean water per year.
With an estimated 1 million acre-feet of irrigation drainage available for treatment and reuse in the Central Valley, it’s just possible that this new brand of desalination – solar-powered, decentralized and focused on water treatment and reuse – could give farmers and rural communities a sustainable new water source and open up new possibilities for keeping more flow in depleted rivers and streams.

National Geographic Newswatch

12 Comments on "Solar Desalination Could be a Game Changer for California Farms"

  1. JuanP on Wed, 22nd Jul 2015 8:33 am 

    I hope that using solar desalination everywhere in the world allows us to grow our global population to 15, 25, or 925 billion people. I can clearly see how that would make the world a much better place for your children to live in. But, maybe, nuclear fusion will beat. Solar to it. Then, with all that water and energy available to us, colonizing the solar system would be a piece of cake. And that would allow us to conquer the Multiverse and rule all creation. Amen!

  2. Lawfish1964 on Wed, 22nd Jul 2015 11:46 am 

    Haha, JuanP! Good one. I guess California is saved! Of course, that won’t make any difference to Lake Mead once the water level drops to 950 feet and power generation ceases. That will be a pretty big whoopsie!

  3. Davy on Wed, 22nd Jul 2015 12:33 pm 

    I farmed around 1000 acres of corn and soy in 2000. I did this for 4 years and got my ass kicked. IOW I got an education on growing things the modern way. I did not lose money I just worked for 4 years for free to who I don’t know but someone got a free lunch from my sweat. I am doing a small permaculture cattle and goat operation now. This is much different and a wonderful occupation I highly recommend.

    I see multiple problems with this technology. Margins in industrial agriculture are extremely narrow. This is why you need volume from broad acres and large equipment. Permaculture and simple living is another animal. This technology might work wonderfully with that arrangement. Keeping it small, efficient, and low demand.

    Being a student of dynamic system impacts of marginal returns of complexity and resource limits I see this as just another case of sounding wonderful but not scaling or offering an adequate return. These farmers and the wider society are already stressed on multiple fronts. There is a point where there is just not enough money to grow things in a hostile environment especially the way Californian people like to live. I think there is a place for this technology in the niche areas and with small scale applications but not wide spread applications. We see these technological ideas come and go constantly. This is just a rerun.

  4. Westexasfanclub on Thu, 23rd Jul 2015 5:04 am 

    Davy, in terms of BAU you are probably right. But when it comes to survival this kind of technology can make the difference.

    Remember how war industry worked in WWII all over the planet: It wasn’t profit orientated. Things had to be done and were done just for the sake of survival.

    A post peak resource world will be very much like a world in a state of permanent war. Will mankind win that war? That indeed is another question.

  5. Davy on Thu, 23rd Jul 2015 7:33 am 

    West Tex, I agree to a point. WWII had abundant resources of all kinds and a lower population. We have too many people and depleted resources today. All we have to crow about is technology and efficiency. Both of these complexities are very unsustainable and non resilient when they reach limits and declining marginal returns.

  6. Westexasfanclub on Thu, 23rd Jul 2015 8:23 am 

    This is all like a fascinating experiment with uncertain result. Just that it’s not an experiment but our very reality. We and/or our children will see how it all is going to play out. Still hope we find a medium point where things become stable.

  7. ghung on Thu, 23rd Jul 2015 9:08 am 

    The question is: What level of industrial economy does it take to produce and maintain stuff like plastic pipe? Filter membranes? Control systems? modern electric pumps? At what cost? Paid for by whom? In a debt-swamped financial system, what means of exchange? Schemes such as large-scale desalination rely on long, complex supply chains to be viable; not something one builds from salvaged parts in the shop out back.

  8. idontknowmyself on Thu, 23rd Jul 2015 10:24 am 

    Big solar still should be explored before using a lot of complex technologies. Typical of this society. go full retard on complexes technologies.

  9. Lawfish1964 on Thu, 23rd Jul 2015 1:31 pm 

    This reminds me of the old bit Sam Kinison used to do about giving the starving people in the desert U-Hauls. You know, it occurred to us as we were driving out here for the 40th or 50th time that there wouldn’t be world hunger if you people would live where the FOOD IS!!!

    If I lived in California, I’d move. Forget about trying to desalinate water. Go somewhere where water falls from the sky.

  10. apneaman on Thu, 23rd Jul 2015 1:35 pm 

    More tech

    Why the Great Glitch of July 8th Should Scare You

  11. Northwest Resident on Thu, 23rd Jul 2015 1:52 pm 

    I know a guy in SoCal who lives on his 50-foot sailboat with his wife and dog. He has a solar powered desalination unit on his boat that he says produces 8 gallons of fresh water hourly, which he figures is more than enough for his survival needs which includes not just drinking/cooking/cleaning water, but water for his onboard tomato and assorted veggie plants-in-pots too. He figures that when TSHTF, they can just sail a brief way to his favorite fishing “hole” about six miles off the coastline and float and live there indefinitely. Not a bad plan and definitely not a bad setup if you ask me.

  12. Kenz300 on Fri, 24th Jul 2015 9:24 am 

    Wind and solar are the past, present and future of energy generation……. safe, clean, reliable and declining in cost.

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