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DesalData Weekly - November 26, 2015

Posted 26 November, 2015 by Mandy

SingaporeThe national water agency of Singapore, the Public Utility Board (PUB), has selected the civil engineering company HSL Constructor to design and construct the nation’s third desalination facility.  HSL Constructor bid $153 million (USD) for the plant, which will be located in Tuas.  The plant will operate at a capacity of 136,000 cubic metres per day, the same as the nation’s first facility, which is less than half of the production capacity of the second plant at Tuaspring (which is over 300,000 cubic metres per day). Construction will begin in 2017.



 

 

[1] [2]

Singapore has overcome previous water shortages by investing in research, technology, and infrastructure that allows the country to draw water from four different sources, including water from local catchment areas, imported water, reclaimed water, and desalinated water. 

Currently, desalinated water comprises 25 percent of Singapore’s water supply.  PUB plans to increase its supply of desalinated water in order to continue to provide the same ratio of desalinated water to the nation in 2060.[3]  Plans are already in place for a fourth desalination plant in eastern Singapore, at Marina East, which will have a capacity of 136,400 cubic metres per day and the capability to treat freshwater from the Marina Reservoir in Marina Bay (which provides 10 percent of the island’s water needs).[4] 

In the UAE, the early stages of advanced trials on renewable, energy-efficient desalination technology indicate promising results. Since May 2014, four companies have been working on pilot projects to develop desalination technology that is renewable and energy efficient.[5]  Working as part of the Masdar Renewable Energy Seawater Desalination Program, they have built pilot plants in Ghantoot, Abu Dhabi, which habe been producing potable water since this August.  The plants are operating in accord with the technical constraints of a large plant and it is handling harsh seawater conditions—with harmful algal blooms, temperatures exceeding 42° Celsius, and salinity levels of up to 52 g/l.[6] 

Veolia, one of the four companies involved, says that their trial demonstrates a 7 percent reduction in electrical energy consumption (in relation to the contractual target that Masdar initially required).  These energy savings, when combined with those of a new pretreatment design, can save 25 percent on civil costs, and thus reduce the footprint of the plant as well as its capital expenditure (i.e. the funds used to acquire or improve on its physical or non-consumable assets such as property or equipment).[7]

Graduate student Savvina Loutatidou, who is working on geothermal desalination

Graduate student Savvina Loutatidou, who is working on geothermal desalination      Credit: The National.ae

 

Meanwhile, at the Masdar Institute of the UAE—which focuses on alternative energy and sustainability for the region—graduate students are researching methods to produce drinking water from geothermal energy.  Geothermal desalination, which uses heat energy from extracted hot water in underground aquifers, was originally conceived of by the entrepreneur Douglas Firestone in 1995; and since 1998, various experiments or trials have been carried out, but the process is still under development.  Savvina Loutatidou, a graduate student at the Institute, believes that researchers should investigate this under-explored resource, irrespective of the utility and promise of solar technologies.[8]   

The European Geothermal Energy Council reports that “low enthalpy (t>60°C) geothermal energy can effectively drive a sea or brackish water desalination unit in order to produce fresh water.”[9]  The Council further endorses geothermal energy for desalination processes, explaining that the energy can provide a stable and reliable heat supply around the clock, 365 days a year, ensuring the stability of the process; the geothermal production technology is mature; and MED desalination—the most cost effective method for use with geothermal heat—is more efficient and uses less electrical energy than other thermal technologies, therefore maximizing water output and minimizing corresponding costs.  Additionally, the method is environmentally friendly, releasing zero emission of air pollutants and greenhouse gases.[10]

Geothermal resources in the UAE provide heated temperatures of up to 150 degrees Celsius, compared to higher temperature resources that produce temperatures of up to 300 degrees Celsius.  This means that geothermal energy may be suited for cooling and desalination rather than power generation.   Loutatidou’s research shows that geothermal desalination would cost roughly $2.50 (USD) per cubic metre of desalinated water—compared to thermal desalination prices that range from $.67-$1.50 (n.b. in places where low cost steam is available).[11]    At the moment, these comparatively higher costs outweigh the benefits of geothermal desalination as a renewable resource.   Further research, however, may reveal more competitive pricing that could bring the technology into the mainstream.

 


[1] “HSL Constructor to Build Singapore’s Third Desalination Plant in Tuas,” Channel News Asia, November 16, 2015, <http://www.channelnewsasia.com/news/singapore/hsl-constructor-to-build/2265030.html> accessed November 20, 2015.

[2] Tom Freyberg, “Singapore’s Third Desalination Project to be Delivered by HSL Constructor,” Water World, November 16, 2015, <http://www.waterworld.com/articles/wwi/2015/11/singapore-s-third-desalination-project-to-be-delivered-by-hsl-constructor.html> accessed November 24, 2015.

[3] Ibid.

[4] See “PUB to build fourth Desalination Plant in Singapore,” September 3, 2015, Water World, <http://www.waterworld.com/articles/2015/09/pub-to-build-fourth-desalination-plant.html> accessed November 24, 2015.  See also, “Marina Reservoir,” PUB, Singapore’s National Water Agency, <http://www.pub.gov.sg/Marina/Pages/mr.aspx> accessed November 25, 2015.

[5] Andrew Williams, “Scaling Up the Middle East’s Renewable Desalination,” Industrial Water World, <http://www.waterworld.com/articles/wwi/print/volume-30/issue-1/regional-spotlight-mena/scaling-up-the-middle-east-s-renewable-desalination.html> accessed November 25, 2015.

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[6] “Desalination Trials in UAE Show 7% Energy Saving on Masdar Target,” November 23, 2015, Water World, <http://www.waterworld.com/articles/wwi/2015/11/desalination-trials-in-uae-show-7-energy-saving-on-masdar-target.html> accessed November 25, 2015.

[7] Ibid.

[8] LeAnne Graves, “Masdar Research Boils up Hot Idea for Water Desalination, November 21, 2015, <http://www.thenational.ae/business/economy/masdar-research-boils-up-hot-idea-for-water-desalination> accessed November 24, 2015.

[9] “Geothermal Desalination,” European Geothermal Energy Council, <http://egec.info/wp-content/uploads/2011/03/Brochure-DESALINATION1.pdf> accessed November 25, 2015.

[10] Ibid.

[11] Graves, “Masdar Research.”

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