Desalination and Alternative Water Supply and Efficiency

President John. F. Kennedy once said, “If we could produce freshwater from saltwater at a low cost, that would indeed be a great service to humanity, and would dwarf any other scientific accomplishment.” However hopeful President Kennedy’s words were, he was referring to basic groundwater desalination projects, and not the centralized, large-scale projects of seawater desalination that are proposed near coastal U.S. cities today. It is important to note the distinction between groundwater desalination and seawater desalination, the latter containing much higher concentrations of salt, which leads to heavy construction costs, significant ocean and coastal ecosystem impacts, and higher energy and water prices. Seawater desalination development in U.S. coastal cities needs to be weighed economically against alternative water supply and efficiency measures, while acknowledging the social change in human consumption of energy and water use that is necessary to address emergency drought planning and the changing baseline of our environment

Generally, desalination is a process of treating saline or impaired waters, also called brackish water, to produce a stream of freshwater for human consumption. A second, much saltier stream is produced in the process, called waste concentrate or brine. Seawater desalination is a hopeful technological solution for industry, farmers, and residents that do not want their businesses interrupted by water shortage, drought, and rising cost. Some environmentalists also look favorably upon seawater desalination; they want to conserve the Earth’s freshwater for other species and other beneficial use. Others are more cautious, arguing the technology is new and expensive, which results in wasteful upfront spending, legacy grey infrastructure, and shortsighted profit margins. These proponents also argue that if desalination plants are built, industry, farmers, and residents will be less inclined to change water use behaviors. The U.S. could use alternative water supply and efficiency instead, which is currently more cost effective. While simplistic videos of desalination are popular on social media, urban planning of large scale development of seawater desalination on U.S. coastlines is a much more complex environmental, economical, and political discussion.

First, desalination plants require large upfront investment to cover capital costs, and project financing is a key challenge for any capital-intensive project. In 2004, the Carlsbad Desalination Plant in Southern California, the largest in the U.S., was projected to cost $250 million; however, when it ultimately opened in 2015, the final cost totaled over $1 billion. In project financing, the debt is not based on the project sponsors credit, but the project performance. This means the funding is based on the desalination plant’s revenues into the far future, which are contingent on water and energy markets, regulatory changes, and the environment’s changing baseline. The Carlsbad plant reached a 30 year water purchase agreement with the local water authority. Basing the price on thirty years of project performance, which relies on both fluctuating water and energy prices, is dangerous, especially in tandem with the serious progression of climate change. One can also imagine more stringent regulations being proposed regarding ocean and coastal ecosystems as these environmental impacts are studied more.

Why not spend big on our current water infrastructure? Besides the huge cost, it takes over 10 years to plan and fund a seawater desalination plant. The construction of expensive legacy systems also amplifies the incentive to build seawalls and bulwarks along our nation’s coast, while rising sea-levels are an exponentially increasing concern for coastal cities. Cities should be utilizing expensive coastline real estate to adapt to the effects of climate change to address increases in heat-waves, storm surges, and inundation.[1] What makes the discussion more difficult is that the three states that are most involved in desalination project planning – California, Texas, and Florida – accounted for 48 percent of U.S. population growth between 2014 and 2015, which complicate how seawater desalination

Second, seawater desalination intake cooling structures on coastlines effectuate potentially devastating environmental impacts on coastal ecosystems. Intaking of seawater and the disposal of salt waste are the most significant threat to ocean and coastal ecosystems. The former has two major concerns: impingement and entrainment. Impingement transpires when fish and other large organisms are trapped on the intake screen, which results in death or injury. Entrainment kills smaller organisms, like plankton, fish eggs, and larvae that are small enough to pass through the intake screen during the desalination process. Entrained organisms are killed by pressure and velocity, chlorine and other chemicals, and predators like mussels and barnacles on the intake pipes. Although scientists have yet to come to a conclusive answer to what the total negative effects of desalination are on ocean and coastal ecosystems due to the sheer volume of water that would require study, it is in the best interests of these ecosystems to proceed with various precautionary measures. There are ways of addressing impingement and entrainment impacts, such as co-location (using secondhand wastewater from thermoelectric power plants instead of the ocean) and underground intake cooling structures (using underground intake pipes to avoid impingement and entrainment altogether). Nevertheless, co-location relies on the supply of seawater from the continued operation of the co-located power plant. If the plant shuts down, then the seawater desalination plant will have to use more energy to intake their own water at all times. Underground intake pipes add significant cost to project construction and result in different environmental impacts like periodic dredging.

Disposal of brine, the saltier waste concentrate, is a significant worry. Two major waste streams occur during disposal: brine and spent cleaning solutions. The cleaning solution used to treat intake pipes and filter screens, while much smaller than the brine amount, is still capable of contaminating the environment.[2] Yet, the potent concern with significant development of desalination on U.S. coasts is elevated salinity levels from disposal of brine back into the ocean. Even assuming that desalination plants could not possibly over-salt the vast ocean as a whole, other prominent concerns remain, such as the presence of heavy metals, natural constituents, thermal pollution, and brine dispersion concentrated along vibrant coastal ecosystems. While coastal ecosystems remain the hotter topic within the desalination debate, the equitable distribution of safe drinking-water is being studied by organizations like the World Health Organization.

Finally, seawater desalination consumes more energy per gallon than other water supply and treatment options. Although energy consumption varies based on site design and location, on average, they use 15 MWh per million gallons of water produced as compared to groundwater and surface water which require 0 – 3.4 MWh. Moreover, desalination purely powered by renewable energy is at most a hopeful fantasy when hooking up the plant to the electric grid can save immediate project construction costs for the private developer. According to a Pacific Institute study, a 1% increase in emissions would result if all the proposed seawater desalination plants proposed in California were built. In Southern California water pricing per acre foot is also telling: seawater desalination ($2,000), imported water ($1059), groundwater ($402). Although others argue technological innovation will lessen the price gap, Southern California’s residential water price could increase $3-$6 dollars. Alternative water supply and efficiency can address drought issues without creating higher energy demand and an increase in water price.

Organizations like the International Desalination Association and the Texas Desalination Association continue to research and implement desalination offering “drought-proof” solutions, while others like the nonprofit Surfrider Foundation intend on making sure seawater desalination plants are appropriately built by litigating the construction of the Carlsbad plant in California. Surfrider appealed the California Regional Water Quality Board’s decision to approve a National Pollutant Discharge Elimination System permit to discharge brine and intake seawater, but an appellate court denied Surfrider’s claim that the Carlsbad plant did not follow California Water Code, which provides “[f]or each new or expanded coastal power plant or other industrial installation using seawater for cooling, heating, or industrial processing, the best available site, design, technology, and mitigation measures feasible shall be used to minimize the intake and mortality of all forms of marine life.” Surfrider Foundation v. California Regional Water Quality Bd., 211 Cal.App.4th 557 (2012). The court weighed factors such as co-location, mitigation of wetlands, underground intake pipes, and other technologies in favor of the water authority. Environmental groups should make sure seawater desalination plants are built in proper locations with mitigation mechanisms like California in Texas and Florida, where similar provisions are less stringent.

While not many cases discuss the environmental impacts of seawater desalination, legislation is bound to address these issues during Donald J. Trump’s Presidency. Most recently S.2533, authored by Senator Feinstein of California, and other related bills, seek to address emergency drought planning and alternative water supply and efficiency. It is up to President Trump’s new administration to present a infrastructure plan that is cautious yet considers the social change that is necessary to address drought and the changing baseline of our environment.

[1] Robert I. McDonald, Conservation for Cities, (2015).

[2] Heather Cooley et al., Pac. Inst., Key Issues in Seawater Desalination: Marine Impacts 12 (2012) (describing various chemical additives such as coagulants, antiscalants, and biocides: “[t]he majority of [which] are added during the pretreatment process to prevent membrane fouling,” and such that can harm marine life).

Cody Stryker

Cody D. Stryker is a second-year law student at Vermont Law School pursuing his J.D. and Master’s of Energy Regulation and Law, where he focuses on the intersection between water and energy. At VLS, Cody is a staff editor for the Vermont Journal of Environmental Law and a Senator of the Student Bar Association. Cody gives special thanks to VLS Professors who have shown immense courage and optimism over this past election cycle.