Despite some early March rain in California, and a few storm systems moving in this week, the late season moisture will sadly fall far short of that which is needed to pull the state out of its four-year drought. Attention has consequently turned towards how California will ensure reliable water supplies in years ahead, should precipitation levels remain below average.
One source that will grow in importance is desalination, and it could end up being a pretty big business. Environmental Leader reported earlier this month that the components alone for desalination activity will constitute a $5 billion industry by 2015, and while this spend would not be confined to California, the report, conducted by the McIlvaine Co., describes the state as being at the epicenter of global desalination activity.
According to SFGate, the San Francisco Chronicle’s online news outlet, 17 desalination plants are in the planning stages in the state of California, and of these, the largest one in Carlsbad, near San Diego, is two years away from completion. When the plant is switched on, it will be the biggest desalination facility in the Western Hemisphere, taking water from the Pacific Ocean and turning it into around 50 million gallons of potable water daily — serving 110,000 customers in San Diego County.
To build such a plant, water treatment chemicals, pumps, valves and centrifuges are among the many components that will be required. The process of desalination for the Carlsbad plant involves “reverse osmosis,” which entails forcing salty or brackish water through screens to filter out contaminants. The cross-flow membrane equipment involved in the filtration process, according to the McIlvaine Co., constitutes the most costly of all components, which alone constitutes a $3.06 billion market.
But despite this being a big business, desalination is something of a solution of last resort as far as solving the water supply problem goes, because reverse osmosis demands huge amounts of energy and is expensive. As a result, the cost to produce an acre-foot of water runs at about $2,000. An acre-foot is the volume of water needed to cover one acre in one foot of water, and is considered enough to provide water for two families of four for a year.
To put that cost into context, SFGate notes, surface water from reservoirs and mountain runoff during plentiful years can be as cheap as $100 per acre-foot. Desalination, therefore, comes at a significant price premium. But then again, these are not plentiful years. SFGate reports some California farmers may have to acquire water this year on spot markets and will face paying up to $3,500 per acre-foot — making the economics of desalination more attractive.
But still, cost aside, desalination via reverse osmosis has its critics, who cite environmental concerns. Marine life is threatened, as the desalination plants may suck in fish from the oceans or delta along with water, and CO2 emissions would increase due to the large amounts of energy required to operate the facilities.
One innovation that may help farmers in the central valley however, may be a solution that we can get more excited about. Earlier this month, SFGate reported on a startup called WaterFX operating in the Panoche Water and Drainage District that’s testing a solar-thermal desalination plant — which at the moment is producing a meager 14,000 gallons per day, though the company hopes this will grow by several orders of magnitude in the future.
The solar desalination plant treats irrigation runoff, which has accumulated salt and naturally occurring chemicals rendering it unfit for human consumption or new irrigation. Unlike reverse osmosis, the system uses solar thermal energy to evaporate and distill water at 30 times the efficiency of a standard solar still. WaterFX’s product, The Aqua4™, uses advanced absorption technology to dramatically increase production. As water passes through the distillation system, steam is captured and condensed into potable water, while the remaining salt brine is concentrated and separated out in a solid state. The brine coprouducts can be sold as useful resources in their own right. This has the happy side benefit of dealing with the waste stream that you would normally get with traditional desalination methods.
WaterFX is currently trying to raise capital to scale-up, and if successful, the company has plans to expand their operation that would produce 2,200 acre-feet of purified water per year . Best of all, using solar energy avoids the huge energy cost of reverse osmosis and produces clean water at the cost of about $450 per acre-foot.
Of course, this is a discussion on the supply side only. Let’s not forget there’s a huge opportunity as well for conservation. The California Water Impact Network, which advocates for environmentally sensitive uses of California’s water, notes that water recycling is a proven option that can cost as little as $300 per acre-foot, though it can run higher than this.
Either way, scarcity is driving innovation — and it should continue even if rain is plentiful in seasons to come, because whether or not climate change is exacerbating the current drought, California has a long history of protracted dry periods. With a growing population, a few wetter years are not going to be a long-term fix for the state’s water problems.
Image Credit: Don DeBold
Follow me on Twitter: @PhilCovBlog
Editor’s Note: This post was updated on April 1, 2014 to clarify technical aspects of The Aqua4™ desalination process.