Desalination: A Drought Proof Supply?
It seems not a matter of if but when seawater desalination will fulfill the promise of providing parts of California with a reliable, drought-proof source of water. With a continuing drought and uncertain water deliveries, the state is in the grip of a full-on water crisis, and there are many people who see desalination as a way to provide some relief to areas struggling to maintain an adequate water supply.
“The current situation has heightened the need for reliable sources of water, especially in these type of times when there is rationing across the state,” said Paul Shoenberger, assistant general manager with the West Basin Municipal Water District in Carson and chair of a desalination subcommittee for the Association of California Water Agencies. “Desalination is more available and isn’t linked to rain or snowpack.”
Desalination’s potential has changed significantly since the drought of the late 1980s and early 1990s. At that time, desalination had barely emerged from being a niche technology reserved for specialized applications and was not in a position to be considered a legitimate source of water supply augmentation. But circumstances and ingenuity have moved desalination much farther ahead to the point where its role in serving part of future water needs is nearly assured.
“Desalination technology offers the potential to convert the almost inexhaustible supply of seawater and apparently vast quantities of brackish groundwater into a new source of fresh water,” states a 2008 report from the National Research Council (NRC), Desalination: A National Perspective. “Technological advances over the past 40 years have reduced its cost and have led to dramatic increases in its use worldwide. However, a host of financial, social, and environmental factors still impede its use.”
Some water agencies view desalination as a means to stabilize a portion of their overall supply that has become increasingly vulnerable to drought and regulatory cutbacks. “The benefits are that it is a local, reliable source of water, independent of hydrology, drought, or whatever,” Shoenberger said. “To a large extent, it is independent of water rights and other complicating issues and it’s a very high quality source of water.”
But desalination comes at a cost. Plants are expensive to build, although technological improvements have eased the financial burden, and there are environmental impacts. “Many plants use subsurface intakes, which significantly reduce the adverse effects on marine life and in many cases reduce a facility’s operating costs due to lower pre-treatment requirements,” said Tom Luster, an environmental scientist with the Coastal Commission.
Then there are the necessary energy requirements to wring the salt from seawater. Seawater is about 35,000 parts per million (ppm) total dissolved solids. A 50 million-gallon-per-day (mgd) desalination plant uses about 33 megawatts (MW) of power, according to the Department of Water Resources (DWR). (One MW generally provides enough electricity for 400 to 900 homes). Because of the “energy intensity” of the desalination process, “energy consumption represents a major portion of the direct operation and maintenance expenses of a desalination plant,” DWR says in its draft 2009 California Water Plan Update.
Desalination proponents say its energy requirements have to be kept in perspective when weighed against other sources of electricity consumption. “It requires more energy to air condition a home in the warm inland areas of California than it does to create all the water that same household uses,” said Bob Castle, water quality manager with the Marin Municipal Water District. “So I have to ask why desal is considered such a bogeyman when the energy for air conditioning isn’t held to the same scrutiny.”
Desalination in California took a large step forward this year as regulators gave final approval to a $300 million, 50 million gallons per day (mgd) facility in Carlsbad in northern San Diego County. The project by Poseidon Resources – the largest of its kind in the nation – took six years of permitting and review and is expected to begin providing drinking water to several contracted local water providers by 2012, including the city of Carlsbad, which will receive its entire daily water requirement. During its review, the plant was illustrative of many of the issues related to costs, environmental impacts and energy use.
Those analyzing the prospects of desalination cite costs as one of the primary issues to be considered. “The price of desalination has been falling with technological advances … nonetheless, the cost remains high at an estimated $1,000 per acre-foot before subsidies,” the Los Angeles County Economic Development Corporation concluded in a 2008 report, Where Will We Get the Water? Assessing Southern California’s Future Water Strategies. (An acre-foot, about 326,000 gallons, can meet the yearly water needs of one to two California households).
Once the water is desalted, the concentrated brine solution must be disposed of in a way that does not harm the marine environment. Safe disposal of the brine, which may contain other pollutants, “is a challenge,” the Pacific Institute said in its 2006 report, Desalination, With a Grain of Salt: A California Perspective. The group says more research is needed “to adequately identify all contaminants in desalination brines and to mitigate the impacts of brine discharge.”
These operational costs and environmental impacts are a concern for water agencies investigating desalination opportunities. According to the city of Long Beach, which is pursuing desalination, immediate investment “is not a cost-effective option for water supply reliability … primarily due to the high cost of energy needed for operations and several abrasive environmental impacts.” Officials there believe desalination will eventually become part of the water supply portfolio as conditions warrant.
State officials for years have reviewed the viability of desalination as a functioning part of the overall water supply portfolio and the push toward more regional self-sufficiency. The draft 2009 Water Plan Update notes that while desalination “has historically been prohibitively expensive,” technological improvements and the rising cost of conventional water supplies have brought it on par with imported water and recycled water “in a number of cases.”
Desalination “should be considered, where economically and environmentally appropriate, as an element of a balanced water supply portfolio, which also includes conservation and recycling to the maximum extent practicable,” the draft report says.
Critics of desalination say they are not against the technology on principle but that there are substantial issues about the impacts to marine life and the amount of energy required to power the process. There also have been concerns about the public-private partnership associated with desalination projects and the potential costs to ratepayers.
“We still haven’t answered all the questions about seawater desalination,” said Conner Everts, co-chair of the Desal Response Group in Santa Monica, which advocates water conservation and recycling ahead of seawater desalination. “We continue to have questions. [Desalination] is almost like a religion. People see it as a one-way street.”
Building a seawater desalination plant can be a challenge because of the concerns about costs for construction and treated water and the environmental impacts. In the San Francisco Bay Area officials have contemplated a 5 mgd desalination plant to supply water to parts of Marin County but the process has not been easy. “We don’t believe that we can resolve our water supply/demand imbalance with conservation and recycling alone,” Castle said. “A supplemental supply is needed and there are only hard choices.” But the proposed Marin plant has sparked controversy over concerns related to environmental impacts and growth. (See page 9 for more information.)
Alternative water use strategies, be they desalination or water recycling, are supported and opposed to varying degrees by advocacy groups. Reuse of highly treated wastewater is viewed as a necessity in some areas but retains a stigma from a public perception point of view. From a technical perspective, experts say the costs of desalination and recycling are highly dependent on factors unique to individual projects, such as project size and transmission requirements.
Seawater desalination has support and opposition within the environmental community. Some are encouraged that locally developed sources of water in Southern California can take some pressure off strained northern waterways that provide water for export. Assemblymember Jared Huffman, D-San Rafael, who spent several years as an environmental attorney with the Natural Resources Defense Council, said while he is “not beating the drum” to build desalination plants along the coast, if projects are “careful and selective it is a tool that ought to be on the table.” Huffman, who chairs the Assembly’s Water, Parks and Wildlife Committee, said state officials can help by streamlining the regulatory process and rewarding desalination projects that use creative designs that minimize environmental impacts and energy use.
Substantial financial resources have been invested in seawater and brackish groundwater desalination. Seawater desalination has gained momentum recently due to several factors, including technological advances that have moved it to a more cost-competitive position with other water sources.
“The cost of seawater desalination has been going down steadily for years – half the cost it was 10-15 years ago – and is projected to decrease [more] as a result of technological advances in reverse osmosis membranes and energy recovery devices,” said Scott Maloni, vice president with Poseidon Resources in San Diego.
But the Coastal Commission’s Luster said the downward cost projections “may no longer be correct” and that in fact desalination costs during the last several years have risen, mostly due to increasing energy costs and the higher costs of financing a facility.
Maloni with Poseidon said construction costs “are somewhat down due to the impact the global economy is having on the commodities market,” a development that is “true throughout the construction world and not unique to desalination projects.”
This issue of Western Water examines desalination – an issue that is marked by great optimism and controversy – and the expected role it might play as an alternative water supply strategy.
Click here to purchase a copy of the entire article.
While this magazine, our other publications, school programs and daily news blog, Aquafornia, reach thousands of people daily, public television programs reach millions in California and throughout the country. That’s why almost 20 years ago the Foundation formed a partnership with public television to produce documentaries on water issues. Two programs have won regional Emmys – Fate of the Jewel, about pollution threatening Lake Tahoe, and High Stakes at the Salton Sea, about efforts to restore the Salton Sea. We were excited to learn this spring that the Foundation and our production group received two Emmy nominations for our latest program on the Central Valley’s salinity problem.
In May I had the honor of attending the 38th Annual Northern California Emmy Awards ceremony in San Francisco. The Foundation’s sponsored program, Salt of the Earth: Salinity in California’s Central Valley, presented by KVPT, Valley Public Television in Fresno, won a regional Emmy from the National Academy of Television Arts and Sciences for best writing of a documentary. Major funding and technical advice for the documentary was provided by the Foundation with additional assistance from the California State Water Resources Control Board and the California Water Institute. The Foundation has been covering the salinity issue in the Central Valley for many years and we were glad to make this documentary hosted by comedian Paul Rodriguez. This gala formal event was held at the Palace Hotel in San Francisco My husband, John, and I took the train from Sacramento and arrived at our hotel just in time to change for the event. John forgot his dress shoes and was all set to wear his hiking shoes to the event until he talked to our grown daughter Suzanne, who served as a quick marriage counselor, and convinced him to get to Macy’s right away and get a new pair of dress shoes.
While I was excited to attend the ceremony, the night was bittersweet because for personal reasons our producers, Karen Christian and John Davis, were not able to attend. We were seated towards the back of the room, and as I watched all the winners accepting I noticed they were all seated toward the front so I thought this meant we weren’t going to win. When the winner for writing was announced I was thrilled to hear Salt of the Earth.
After I made it to the stage I emphasized the importance of this issue: “When we were children we learned of a land called Mesopotamia, and because of lack of water and poor agricultural practices, the land salted up and became unproductive, and it is now a place we call Iraq. So thank you for letting us shed some light on a problem that also affects California’s great Central Valley. And thanks for the team who helped us on this great documentary.”
It was an honor to be there and I truly am proud of everyone who worked to make this documentary a success. I hope you will watch it on your local public television station and get a copy from the Foundation.
In the News
Long-Awaited Flows Set to Return to San Joaquin River
Water is set to flow again on the San Joaquin River in a few months – the beginning of a long-awaited restoration of a river that has been dry in some stretches for decades.
A draft Fisheries Management Plan released June 3 by the U.S.
Bureau of Reclamation (Reclamation) lays out the blueprint for
the initial releases from Friant Dam. The river flows are part of
the settlement reached among environmentalists, government
officials and the Friant Water Authority that seeks the return of
salmon to the San Joaquin. Built in 1944, Friant Dam created
Millerton Reservoir, which supplies agricultural water to the
east side of the San Joaquin valley through the Friant-Kern
“The purpose of the interim flows is to collect relevant data concerning flows, temperatures, fish needs, seepage losses, recirculation and recapture and reuse,” states a June 3 press release by Reclamation and the California Department of Water Resources.
Initial river flows will help determine how to restore river functions to facilitate salmon habitat. Fish will be re-introduced in 2013. Growers will give up, on average, 170,000 acre-feet of water each year for river restoration, according to the settlement. The flows would be conveyed down the river channel and possibly down the Eastside and Mariposa bypasses to the Sacramento-San Joaquin Delta, according to Reclamation. “To the extent possible” flows would be recaptured by existing water diversion facilities along the river and the Delta for agricultural, municipal and industrial, or fish and wildlife uses.
Reclamation’s plans include “environmental commitments” to avoid, reduce, or minimize impacts to special-status species, a vehicular traffic detour plan, a recreation outreach program and the implementation of a groundwater seepage monitoring and management plan.
“We will need at least five years to make channel improvements and learn all we can about the river,” Jason Phillips, Reclamation’s river restoration program manager, told the Fresno Bee June 14.
President Obama March 29 signed into law an omnibus public lands bill that included authorization and funding for the restoration project. Environmentalists first sought to return water to the dry river more than 20 years ago when a lawsuit challenged the renewal of long-term water service contracts. A judge in 2004 ruled that the operation of Friant Dam violated a section of the California Fish and Game Code that requires dam operators to “allow sufficient water to pass over, around or through the dam, to keep in good condition any fish that may be planted or exist below the dam.”
The landmark settlement in 2006 established the goals of restoring and maintaining fish populations in “good condition” in the mainstem river below the dam to the confluence with the Merced River while reducing or avoiding “adverse water supply impacts” to agricultural contractors, according to Reclamation. The initial releases will give scientists an idea of how much restoration water can be recaptured for use on farms. In addition to the restored salmon habitat, advocates for the re-watering of the river say it will have a positive effect on downstream water quality as more fresh water is introduced to the Sacramento-San Joaquin Delta.
– Gary Pitzer