Published on: 17/06/2008
Publication: Khaleej Times
Country: United Arab Emirates

The UAE's skyrocketing water demand is likely to grow even further as a new consumer, "district cooling", grows in prevalence.

The concept, which entails chilling water in a central plant and then piping it to buildings for cooling, has been marketed as an environmentally friendly alternative to traditional central air-conditioning systems that use chilled air and account for roughly 70 per cent of the country's electricity consumption.

Thanks to efficiencies of scale, district cooling uses almost half the energy of traditional air conditioning - and is therefore responsible for emitting less carbon monoxide and refrigerants in the air. But it has a catch: it takes substantial amounts of water to flow through the cooling network.

George Berbari, the chief executive of DC Pro Engineering, an electro-mechanical engineering firm, estimates that the country's existing district-cooling plants currently consume more than 10 million cubic metres of water - enough to fill 4,000 Olympic-size swimming pools. The industry's water demand is expected to more than double in the next few years cooling capacity more than doubles too, said Mr Berbari.

District cooling, he said, "will grow exponentially" as more and more large development projects adopt the concept.

His company is building 10 new plants in Dubai Motor City, Danat Abu Dhabi and other large developments. All stations of the Dubai Metro, currently under construction, will be cooled through district cooling. It is also being studied by Aldar Properties, while Tabreed, the UAE's first commercial district-cooling company, is looking to double the number of its plants in the UAE to 58.

A study carried out last year by The National Investor, an investment bank, estimated that district-cooling refrigeration capacity in the country would reach four million tonnes by 2012, growing at a compounded rate of 63 per cent per year.

But the popularity of district cooling is adding even more question marks to the country's already strained water equation.

Most of the potable water in the country is produced through desalination, typically by passing seawater through a membrane to remove the salts and make it potable. Desalination, however, requires a lot of energy. Ironically, that means district cooling, by relying on desalinated water, will account for more greenhouse gases being released than other kinds of cooling.
Four years ago, it seemed that the industry was close to solving this dilemma, with Tabreed building the country's first plant capable of using treated sewage rather than potable water. A founding member of that company, Mr Berbari has since designed more than 10 plants that can use effluent as well as potable water.

But bureaucratic hurdles and competition from landscaping mean that the industry is still reliant on potable water, says Mr Berbari. "A year ago, they said it is not allowed to use fresh water [in the capital], but the alternative is not there."
Treated sewage water that is being produced goes toward the maintenance of the emirate's lush green parks. The authorities, said Mr Berbari, "overspent on irrigation. Right now, irrigation is given a priority but district cooling should also be a priority."

Abu Dhabi's sewage is treated at the Mafraq Waste Water Treatment Plant, one of the largest facilities of its kind in the world. Although 60 per cent of the output of 150 million cubic metres a year is used for irrigation, the emirate's landscaping needs are growing so rapidly that even a small portion of potable water goes toward keeping the parks green. Another 40 per cent of the plant's production is released back into the sea because of a lack of infrastructure needed to transport it back to the capital.

Marwan Ghannam, a senior consultant at Hyder Consulting, said that is "a short-term problem" and work was under way to upgrade the pipe network necessary to carry the effluent.

Sources at the Environment Agency - Abu Dhabi have said previously that the issue would be resolved within two years, but this, said Mr Ghannam, would not rectify the problem as the current property boom in Abu Dhabi would create an even larger demand for landscaping.
"The increase in population will lead to an increase in the amount of treated sewage effluent, but even that will not cover the demand of landscaping," he said. "Water demand has to be managed so that it meets a sustainable production rate and not the other way around."

For the landscaping sector, this meant "firm control of private gardening" as well as "careful planning and engineering" of public parks.

One solution could be an increased use of "hard-scaping", such as rocks and tiles, which are visually attractive but do not require any water. Another partial answer lay in the use of more drought-tolerant plants.

In Dubai, where during winter the volume of effluent exceeds landscaping needs, authorities are devising initiatives to encourage district-cooling companies to switch off the use of potable water. But, said Mr Berbari, the process was strewn with bureaucratic hurdles. "The procedure to apply for treated sewage effluent is not yet clear."

Back in 2004, when Tabreed opened the country's first plant capable of using treated sewage effluent, it had taken nine months to obtain the relevant permits from the authorities, he said.