San Diego Water Authority’s New Desalination Plant Shows the Promise and Problems with Responses to the Effects of Global Warming

Is San Diego Water Authority’s new, huge desalination plant a breakthrough response to climate change or a repetition of the same mistakes that prevented us from stopping climate change in the first place?

One of the more harmful consequences of global is growing water scarcity.[1] It’s a challenge that threatens the livelihood and way of life of many, and in so doing, risks pulling countries and regions into conflict over dwindling water resources. Water authorities are on the front lines trying to plan for this challenge, and the San Diego Water Authority has aggressively pursued one new approach: looking out at rising sea levels and seeing a huge potential source of fresh water through desalination. But if its new Carlsbad project – the largest seawater desalination plant in North America – reflects part of the promise for how organizations might respond to global warming, it also illustrates how the misaligned incentives and fragmented decision-making that hinder our ability to prevent global warming bedevil responses to it.

California’s droughts have gotten more severe with climate change and are projected to get worse over the course of the century.[2] Recognizing the environmental and population pressures on its water supplies, the San Diego Water Authority has made lots of progress to reduce water consumption through more conservation, leading to a 12 percent fall in water usage since 1990.[3] Yet over the past ten years it has realized that this is not enough, and pushed to add seawater desalination, an energy intensive process that converts seawater into potable freshwater, as a key part of its water supply by entering into a long-term purchase agreement to secure 7% of its water supply from the new Carlsbad Desalination Plant, the largest seawater desalination plant in North America.[4]



Data from San Diego Water Authority 2015 Urban Water Management Plan

               What’s novel about this isn’t just that it is a different source of supply but how the San Diego Water Authority is being helped to develop it. The advanced technology for the plant comes from IDE Technologies which has developed world-leading desalination plants in Israel. Those plants have now led to water surpluses in what was previously a very water constrained country.[5] The collaboration was facilitated by an agreement signed by Israel’s prime minister and California’s governor that, among other things, called for cooperation on water conservation and sharing of technical expertise. The agreement shows how new forms of international partnerships outside of traditional nation-to-nation diplomacy are emerging between areas suffering similar effects from climate change.[6]

Nonetheless, the San Diego Water Authority’s decision to open a large desalination plant illustrates how some of the same problems hobbling efforts to stop climate change leave organizations with tough trade-offs when trying to respond to its effects.

Water desalination is very energy intensive. Though the energy required has halved over the last 20 years,[7] the Carlsbad plant will still use 38 megawatts a day, enough to power 28,500 homes.[8] At present, that energy usage will not be from renewable resources, so the San Diego Water Authority has moved ahead with a plant that is contributing to the global climate warming whose effects it is trying to deal with locally.

The San Diego Water Authority instead should have announced a commitment to power the plant with renewable energy, if not right away that shortly after its opening. Such an approach would have allowed the Water Authority to set a very positive example that efforts to mitigate the effects of global warming must at a minimum not add more fuel to the fire.

Second, the creation of the plant reveals how fragmented control over resources inhibits cooperation on efforts to manage the effects of global warming in the same way that it makes it tough to limit global emissions in the first place. Only 10% of water used in California is for urban consumption, while 80% goes to agriculture.[9]


Chart from Mother Jones

However, water is not centrally allocated in California, so it can’t easily be most cost-effectively redistributed. As a result, San Diego’s Water Authority is moving ahead with a plant that will produce water costing 2,000 an acre foot, whereas conserving the same amount of water upstream through drip-irrigation would costly only one fourth that amount.[10]

The San Diego Water Authority should have made its expensive desalination plant contingent on commitments from upstream, largely agricultural users of its water sources reducing their water consumption of traditional water sources by equivalent amounts through conservation. Such an approach would leverage the Water Authority’s investment to generate greater water savings, build trust across communities for future, more integrated water agreements, and ensure that drought mitigation efforts don’t fall so heavily on the backs of the urban poor.

Water authorities, like San Diego’s, are benefiting from impressive new technologies to generate freshwater from the sea. The question moving forward is at what cost – to consumers and to the energy use of our planet – we’ll get that water, and if we’ll learn anything from failures to stop global warming in the steps we take to mitigate it.

791 words (excluding citations and title)


[1] “Anthropogenic warming has intensified the recent drought as part of a chronic drying trend that is becoming increasingly detectable and is projected to continue growing throughout the rest of the century.” Contribution of anthropogenic warming to California drought during 2012-2014. Geophysical Research Letters, 28 August 2015.

[2] For Drinking Water in Drought, California Looks Warily to Sea. NY Times.

[3] 2015 Urban Water Management Plan

[4] Israel’s revolutionary water management methods aren’t going to be enough to solve California’s devastating drought Business Insider

[5] Israeli water tech reaching America’s biggest states. Times of Israel.

[6] For Drinking Water in Drought, California Looks Warily to Sea. NY Times.

[7] Nation’s largest ocean desalination plant goes up near San Diego. Mercury News.

[8] Israel’s revolutionary water management methods aren’t going to be enough to solve California’s devastating drought Business Insider

[9] Nation’s largest ocean desalination plant goes up near San Diego. Mercury News.

[10] Nation’s largest ocean desalination plant goes up near San Diego. Mercury News.


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Levi Strauss – Taking the Water Out of Jeans

Student comments on San Diego Water Authority’s New Desalination Plant Shows the Promise and Problems with Responses to the Effects of Global Warming

  1. I found it interesting that the state chose to go with the costlier option of desalination over the use of drip irrigation, so I looked around a bit as well. In an article by KQED (Northern California’s public news station) regarding a desalination plant in Santa Barbara, an interesting fact was highlighted: water in California is supplied by a for-profit organization, in this case it is California American Water Company. This being the case, it is clear that to some, there is great advantage to increasing supply of water (through desalination) as opposed to reducing demand (drip irrigation). Where there’s a corporate interest, lobbying efforts are likely to follow, and politicians can also claim that they’ve created jobs through the construction and operation of a desalination plant. While this may not be the ideal situation for the environment, it certainly helps explain why California might opt for the costlier method of desalination.

    Interestingly in the same article, the author mentions that the Santa Barbara plant may eventually powered by methane from a local landfill, which is another technique that claims to be environmentally friendly but is shrouded in controversy. The KQED article can be found here:

  2. Desalination is a tough one. Water scarcity is real and given global population growth and the effects of climate change on freshwater supply, we are eventually going to depend on producing freshwater through some desalination process. Conservation is important but won’t get us the whole way. Desal technology is advancing quickly — some recent innovations are low-temperature desalination, which can be powered from the waste heat of a neighboring power plant, and distributed solar desalination (WaterFX is one company working on it).

  3. I think conservation of energy alone (regardless of type) will not be enough to have any significant impact of stopping the impact of climate change. The first reason is because of population growth. By 2050, the world population is expected to be 9.6 BN, with growth coming from developing countries (predominantly in Africa). While the population growth in and of itself makes conservation challenging (given that we have more people competing for fewer resources), it is also challenging because the growth is coming from countries that feel that they have a right to growth, which necessarily means further depletion of resources. While I agree with you that desalination plants work against the goal of conserving energy, I believe that they are absolutely necessary to ensure clean water supply in the future. Singapore has been notable for building up its future water resource, now building its fifth water desalination plant. I agree with Alex that as technology improves, there will be ways to perform desalination in more energy efficient ways but until then I think that the US should continue to invest in building desalination plants around the country.

  4. Drought in SoCal is a real problem we face year after year. The environmental arguments aside there is an ethical question here around profiting from water. The cost of desal has roughly come down by 50% over the last decade but still Poseidon is charging about 2x the cost of wholesale water from the local providers. This essentially will create an access problem for a lot of communities, which will only further hurt small to medium businesses. In terms of climate, the Carlsbad plant is one to watch, there is a plan to use solar panels on its roof to offset its energy consumption. Also, the current Encinitas plant which is the oldest in the region is going offline in 2017, allowing for new cleaner energy to power the Carlsbad desal in the coming years.

    This was a tough decision for San Diego, and I don’t think a full “win” for the community. Ultimately, droughts have been so difficult that it was “good enough” and we just couldn’t wait for a better option.

  5. Thanks for this really interesting post! The San Diego desalination plant is a great example of the tension we discussed in class last week – in trying to address climate challenges, what kind of harm are we creating in the process, and what is the net effect on climate change in the end? As you pointed out, desalination is particularly problematic because it is a very energy intensive process. Considering the water needs in California, the San Diego plant will only make a small dent in meeting overall demand as well, which likely means this tradeoff/tension will become even more relevant in the future. I agree that San Diego needs to enhance local conservation and equitable distribution, and should also look to use renewable sources of energy to power the plant. As private-public partnerships become more prevalent for large infrastructure projects like this, I think the public sector also has to think carefully about long-term tradeoffs for citizens. For example, some concessions might be necessary to attract private capital, but what does this mean for pricing and (as you mentioned) equitable distribution in the long-term? The San Diego desalination project also highlights another tension I often worry about – our dependence on technology and innovation coming to the rescue to address climate change, so we don’t have to make any significant changes to our current behaviors and way of life. I’m hopeful that technology and innovation will result in significant and positive developments, but I worry about over depending on this as well.

  6. As a few of the commenters above have begin to allude to, desalinization struggles with the high energy input required to actually remove the salt and mineral content from the water. While solar provides an attractive option due to San Diego’s climate, the implementation of solar panels over it’s facility cannot keep up with the power demand of the desalinization process. Until a carbon neutral power generation is adopted on a wide scale, this process will be balancing a trade off of GHG generation from power plants and through fresh water supply desalinization. While nuclear power is an attractive options, Fukushima is still fresh in the minds of the world and everyone remembers what happens when you build a nuclear plant near the ocean and an active tectonic fault zone (Southern California has been known to have a few earthquakes). How should the government prioritize incentives in this case? Should desalinization be subsidized at the expense of increased GHG emissions or should the government subsidize greener power sources first in order to make desalinization a non GHG emitting process?

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