Water Energy Matters

Issues related to the water-energy nexus

Desalination, part I: The challenges of applying ethics in water scarcity

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One of the most iconic movie of the 1990’s that foreshadows what the harsh environments of a resource-scarce future may look like is Waterworld. The movie opens with a voice-over narrator explaining that the polar ice caps have melted and the planet is covered by water. The camera pans from an image of Earth into a lone trimaran sailing in a vast, endless sea.

The harsh environmental future of Waterworld. (Video courtesy of YouTube)

Within a few shots, the opening scene has not only established a vibrant image of an extreme and dire future, but has illustrated the conspicuous lack of basic resources that most of us in developed countries take for granted — things such as potable water; land for growing food and raising animals; and means of electricity generation. The male protagonist Mariner, in his post-apocalyptic warrior dress, pees into a small container. He then pours the urine into a rudimentary, homemade filter of funnels and gizmos, and drinks what comes out the other side — a process called desalination.

Drinking one’s own (albeit filtered) urine signals a certain direness under conditions of extreme survival. But desalination — the process by which unpotable water, such as seawater, brackish water, and wastewater, is purified into freshwater for human consumption and use — is not some far-fetched technology we will eventually need in a distant future.

Desalination’s recent global development
Desalination technology has been used for centuries, if not longer, largely as a means to convert seawater to drinking water aboard ships and carriers. Advances in the technology’s development in the last 40 years has allowed desalination to provide water at large scale.

From a global perspective, desalination technology is applied for several purposes: providing freshwater for industrial sectors; supplying drinkable water for the domestic and public sectors; and acquiring water for emergency situations, such as army and refugee operations.

Desalination plays a particularly crucial role in sustaining life and economy in the Persian Gulf. According to Corrado Sommaria, the president of the International Desalination Association (IDA): “Some countries in the Gulf rely on desalination to produce 90 percent or more of their drinking water, and the overall capacity installed in this region amounts to about 40% of the world’s desalinated water capacity.” Much of this is in Saudi Arabia, Kuwait, the United Arab Emirates, Qatar, and Bahrain.

global desalination capacity

Global desalination capacity by country and total capacity. (Image courtesy of Desalination: A National Perspective)

The remaining global capacity is mainly in North America, Europe, Asia (which each have about 15 percent), and North Africa (which has six percent). (A facility’s rated capacity is the full output it is technically capable of, though in reality, it usually produces under that rated value.)  Australia‘s capacity is also increasing substantially. Global desalination capacity has been increasing dramatically since 1960 to its 2008 value of 42 million cubic meters of water daily (m3/day). Of this cumulative capacity, approximately 37 million m3/day is in use. From the above graph, we can see that worldwide desalination capacity more than doubled between 1993 and 2003, and continues to grow steadily today.

Proponents and critics of desalination
Estimates indicate that, by 2025, 1.8 billion people will be living in regions with absolute water scarcity, and two-thirds of the world population could be under stress conditions. Desalinated water is possibly one of the only water resources that does not depend on climate patterns. Desalination appears especially promising and suitable for dry regions.

In one of the country’s biggest infrastructure projects in its history, Australia’s five largest cities are spending $13.2 billion on desalination plants. In two years, when the last plant is scheduled to be up and running, these cities will draw up to one-third of their water from the sea.

Proponents of desalination, like IDA, argue that it sustains population growth, creates jobs, and even supports the development of  energy industries (such as the oil and gas industries in the Middle East). Desalination stops dependence on long-distance water sources and prevents local traditional water sources from being over-exploited. Furthermore, research and development has made great strides in making desalination plants increasingly energy efficient and cost-effective.

However, there are a number of desalination plants worldwide that have been described as uneconomical and unproductive.  Many environmentalists and economists oppose any further expansion of desalination because of its price and effects on the environment. Energy is the most expensive component of running a desalination plant; it is often responsible for one-third to more than half of the cost. Therefore, the cost of desalinated freshwater is more vulnerable to the fluctuation of energy prices than any other water source.

A desalination intake pipeline near Nuweiba, Egypt. (Image courtesy of prilfish)

A desalination intake pipeline near Nuweiba, Egypt. (Image courtesy of prilfish)

Environmentally, desalination plants emits large amounts of greenhouse gas emissions because they are so energy-intense. Furthermore, they degrade marine environments through both the intake and discharge processes. Marine organisms such as invertebrates, fish, and even mammals are killed on the intake screen and smaller organisms, such as eggs, larvae, and smaller fish, that are able to pass through the screen are killed during processing stages. After separating the impurities from the water, the plant discharges the waste, also known as brine, back into the sea. Because brine contains much higher concentrations of salt, it causes harm to the surrounding marine habitat.

In Australia, the mega infrastructure project is drawing fierce criticism and civic protests. Many citizens are angry about rising water bills and environmentalists are wary of the plants’ effect on the climate. Australia relies heavily on coal to generate most of its electricity and is already a major emitter of greenhouse gases — the principle cause of climate change. Ironically, one of the main reasons the country is in need of freshwater is because it’s still recovering from a decade-long drought that the government says was deepened by climate change. Therefore, desalination, which initially appears as an answer for providing freshwater, may in the long run exacerbate the intertwined energy- and water-scarcity cycle.

As scarcity increasingly becomes reality, an appeal to ethics will be challenging
The sentiments of the anti-desalination campaigner in the video below echoes this irony: “It is by a mile the most environmentally-unsound way toward security.” He and other critics say that more environmentally-friendly methods should be exhausted before resorting to desalination. These include mandating more efficient appliances, using less water, or recycling used water.

Australia’s desalination plant provides controversial solution to one of the world’s driest countries. (Video courtesy of Al Jazeera English)

When a society is accustomed to a certain level of access to a resource, it’s hard to ask its citizens to lower their consumption or reuse water based on the argument that it is an ethical choice. In many instances, we observe individual behaviors change in response to policy mandates or market costs. But when can we say that we’ve exhausted all other ways that are less environmentally-damaging? How much should consumption be reduced? How do we decide which water needs are necessary (e.g., water for drinking, agriculture, electricity generation) and which ones aren’t (e.g., water for golf courses) for a certain quality of life?

Waterworld highlights the harsh decisions people face in a scarce-resource future because of the heightened awareness for survival. Pirates raid small pockets of human settlements for resources, they have no qualms about kidnapping a child for the map tattooed on her back, and paranoid atoll residents are willing to kill the Mariner out of distrust. Violence pervades and there is little sense of civility or ethical codes of conduct.

Though the movie is suggested to take place in 2500, it is not hard to imagine that tensions and battling interests over resources will intensify in the not-so-distant future. Making ethical decisions about fair and equal distribution of resources is a challenge today, and will become increasingly more difficult as those resources diminish — even with the most sophisticated of technological developments.

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7 thoughts on “Desalination, part I: The challenges of applying ethics in water scarcity

  1. First, thank you so much for bringing up Waterworld as a segue into your topic. I always though the movie never got enough credit. We can only hope that the fight for basic resources described by the film will not be our near future.
    Secondly, do you know if there has been any effort in finding new and innovative desalination techniques that do not require as much energy?
    I think that in the case of Australia and pumping water from the ocean the technology is still too inefficient and and damaging. But it could be utilized in other areas of the world more effectively, perhaps for low-quality groundwater or wastewater treatment (I am not sure if wastewater treatment and desalination have a lot in common?).
    Thanks for writing on this topic!

  2. I didn’t think that purifying(?) urine counted as desalinization!

    Sort of piggybacking off Aneliya’s comment, it would be interesting to compare the costs of running a wastewater treatment plant versus a desalinization plant. I would think that the latter would be less expensive because you are only removing salt? Actually that is probably not true at all. There are probably tons of microorganisms and other particles in seawater that need to be removed before it is drinkable. Maybe there are synergies that can be capitalized on between WTPs and desalinization plants, if the water purification processes are similar. Would it be economical to have a 2-in-1 plant? Or possible to “retrofit” a WTP to also desalinize water?

    Looking forward to Part 2…

  3. I enjoyed the creative opening of your blog: using Waterworld to introduce the desalination process. I saw the movie in the theater and clearly remember when Kevin Costner cleans and drinks his pee.
    That by 2025 1.8 billion are expected to be living in regions with absolute water scarcity is scary. It’s also unnerving that the desalinization process — something we may need to expand upon due to clear necessity — contributes to climate change and degrades marine environments. Any chance that renewables could be used to run a desalinization plant?

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  7. Like everyone else who has commented on this, I am thrilled that you introduced your post with Waterworld! The power plant that my dad used to work at in Bahrain was right next to the country’s primary desalination plant. I remember going to that area and being shocked at the ‘dead-zone’ that the discharge site had become – no marine plants and certainly no fish, just a turbid, brine mess. I’m really curious as to whether there have been efforts to clean up the discharge before putting it back into the ocean/sea. Is it possible to filter out the salt and use it for something else? Have any desalination plants employed discharge-cleaning methods? And how efficient are they?

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