The water-energy nexus and desalination
- Brooke
- Feb 21, 2018
- 3 min read
A more technical blog post exploring the water-energy nexus and dipping into the topic of the oceans with questions about desalination.
Well-established to some and emerging to others, the "water-energy nexus" is a topic ripe for research-driven technological advancements. This term refers to the inseparable relationship between water and power generation as our water supplies dwindle and our power demands multiply. "Extracting, delivering, and disposing water requires energy, and similarly, many processes for extracting and refining various fuel sources and producing electricity use water." [Siddiqi & Anadon, 2011].
Existing research in the U-Smart Lab at University of Utah explores the optimization of water pumping during times of low electricity cost to store until it is used to generate power during high-cost hours of the day in order to reduce a utility's generation costs [Oikonomou et al. 2018]. Energy storage is one of the largest voids in our electrical grid today and the water-energy nexus, specifically using water as energy storage in reservoirs, represents one creative solution.
However, implementation of any water-energy solution must embrace the standard described by David Orr in his 2007 University of Pennsylvania commencement speech in that the designers "should aim to cause no ugliness, human or ecological, somewhere else or at some later time."
Which brings me to the topic of desalination, which often falls under the umbrella of the water-energy nexus because of its enormous power needs and common integration into power plants for the technologies in which hot steam is required. A recently-installed desalination plant in Perth, Australia takes advantage of renewable energy with a nearby situated wind farm.
I was curious to hear that Perth had built a desalination plant as this city remains a leader in water management. Prior to taking this class, I had dismissed desalination as just another way that humans might ruin the environment. In discovering the nuances of our water crisis, the question of "Where is all our water going?" kept racing through my mind. Generally speaking, we pull water from freshwater sources, use it and pollute it until it cannot be used by the Earth, and send it to our oceans. These processes result in a net transfer of freshwater from the land to the oceans (which pales in comparison to the volume of water added to the oceans by melting glaciers).
My previous dismissal of desalination has now turned into a long list of questions. The first being, "Based on the fact that we are moving freshwater to the oceans without replenishment, does desalination make sense as a method of recovering some of this water?" Jason Antenucci, deputy director of the Centre for Water Research at the University of Western Australia in Perth, leads work that may help answer this question.
"Desalination makes sense as one of several water sources along with conservation, agrees Dr Antenucci. But, he adds, 'to say it is the silver bullet is wrong.'" - The Economist
It may be scale problem, like so many other environmental issues. If every coastal city builds a desalination plant, the impacts on marine life and the entire hydrological system could be detrimental. Desalination is also not getting to the root of the problem. Using recycled water before it gets to the ocean could dramatically decrease our withdrawals from our freshwater sources. The key to any new technology, including desalination, is to research and monitor the existing processes, which the Perth plant appears to be doing well, but must continue in order to populate long-term study data sets that can be used for future decision-making.
Although we haven't formally explored water in the oceans as part of our class, many of these questions have been sitting on the back-burner without disappearing. With the finite time and space available to us, should we focus on only the Earth's freshwater? Should we base our focus on the most pressing, threatened, exploited sources? I will be interested to analyze the expected impact on the exhibit viewers of including oceans versus focusing on rivers, lakes, groundwater.
Sources:
Afreen Siddiqi, Laura Diaz Anadon, The water–energy nexus in Middle East and North Africa,
Energy Policy, Volume 39, Issue 8, 2011, Pages 4529-4540, ISSN 0301-4215, https://doi.org/10.1016/j.enpol.2011.04.023.
(http://www.sciencedirect.com/science/article/pii/S0301421511003065)
K. Oikonomou, M. Parvania and R. Khatami, "Optimal Demand Response Scheduling for Water Distribution Systems," in IEEE Transactions on Industrial Informatics, vol. PP, no. 99, pp. 1-1. doi: 10.1109/TII.2018.2801334
Tapping the oceans http://www.economist.com/node/11484059
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