x Abu Dhabi, UAEFriday 19 January 2018

Sun holds key to a sustainable future

With rising demand for both electricity and water, a more efficient and less damaging means of production is urgently needed.

Water tankers take on fresh supplies for delivery to remote areas of the country not yet served by the water main.
Water tankers take on fresh supplies for delivery to remote areas of the country not yet served by the water main.

At first glance, Umm al Zamoul does not seem the sort of place where the UAE might find an answer to its escalating problem of water supplies. In the desert and some 300km from the capital, it is also far from the sea, which for the past 30 years has been the main source of the nation's drinking water, produced by desalinating the seas of the Gulf and the Indian Ocean.

Yet Umm al Zamoul is home to an experiment being conducted by the Environment Agency-Abu Dhabi (EAD), one that offers hope that the country may be able to break out of a vicious economic and environmental cycle. In March, the Government's Abu Dhabi Water Resources Master Plan spelt out in no uncertain terms the crisis facing Abu Dhabi. Groundwater, which provides more than 70 per cent of total water demand, was being used 24 times faster than it could be replenished.

Reserves have dropped by 18 per cent since 2003 and, at the current rate of use, would be gone altogether within 50 years. According to the master plan, the vast majority of these supplies are brackish and, unless expensively treated, damage the soil when used for agriculture. The small reserves of "sweet" or partially brackish water could be gone in 20 years. In these circumstances, all options are on the table and at Umm al Zamoul the EAD is looking to the sun - after oil, the region's most obvious resource - to power a trial desalination plant. The water it is converting is taken not from the sea, but from far below the ground in one of the country's increasingly saline aquifers. The water is so salty, in fact, that it is twice as saline as the Gulf - itself among the saltiest bodies of seawater in the world.

At the moment, what it produces is a drop in the ocean of desalinated water produced using fossil fuels - two cubic metres per hour, compared with the 97,716 cubic metres per hour supplied to Abu Dhabi in 2007, a total of 856 million cubic metres - but it is a move in the right direction. "These are baby steps," said Dr Mohammed Dawoud, manager of the natural resources department at the EAD, "but this is how innovation starts."

So far the concept is working well. There have been some glitches along the way, he admitted, but the small, solar-powered plant manages to reduce the salt content of the water from 70,000 parts per million (ppm) to 700 ppm, which meets the criterion for potable water. By the end of the year, the EAD will have two more similar installations - near Liwa and in Al Ain - each built at a cost of US$1 million (Dh3.7m). The water will be used to help create habitats for endangered wildlife.

For Dr Dawoud, the project represents a very real opportunity for the UAE to free itself from its reliance on fossil fuels to process water, which is costly economically and, because of the high level of greenhouse emissions, damaging environmentally. "There are," he said, "two alternatives - nuclear power or solar." But the UAE's proposed nuclear energy programme talks about producing electricity by 2020. By contrast, supplies of the natural gas that currently powers its electricity and water co-generation plants are predicted to fall below demand by 2015.

Supply and demand are hurtling in opposite directions. According to the Abu Dhabi Water Resources Master Plan, desalination capacity in the emirate increased by more than 360 per cent between 1998 and 2007. Currently, the emirate has a capacity of 651 million imperial gallons (2.6bn litres) a day, produced by eight plants along its Arabian Gulf coast and one in Fujairah, which supplies Abu Dhabi with water from the Gulf of Oman. The Abu Dhabi Water and Electricity Company projects demand will grow by a further 123 per cent by 2030.

The UAE is not alone in its increasing reliance on desalination, which is echoed around the Gulf. According to the International Desalination Association, Saudi Arabia and the UAE are the world's number one and two in desalination capacity. The two countries plus Kuwait and Qatar account for 38 per cent of the global total. The UAE - to some extent because of the vast investment the plants represent - is dependent on a form of desalination that was state-of-the-art when the programme began in the 1980s, but has now been overtaken by techniques that require less energy to operate and are kinder to the environment.

The country mainly uses "multi-stage flash distillation", a proven and reliable process that has faithfully met the nation's growing water needs for years. However, the Abu Dhabi master plan says it is energy-hungry. According to the report, electricity and water production in the emirate is responsible for 13.5 million tonnes of emissions a year, mostly of the greenhouse gas carbon dioxide. The main fuel powering the UAE's electricity and water plants is natural gas from Qatar's Dolphin field and supplies of this, says the report, prepared by the EAD in collaboration with the Dubai-based International Centre for Biosaline Agriculture, are expected to fall short within five or six years.

It is a gap that cannot be bridged in time by nuclear power and, says Dr Dawoud, it will be a long time before the Umm al Zamoul project can be scaled up. In the meantime, more conventional alternatives offer a workable compromise. According to the International Desalination Association, the majority of desalination plants being built today use a less energy-intensive technique called reverse osmosis, in which sea water is passed under pressure through a series of membranes. This has been around for years, but previously was too expensive. Developments in membrane technology have now shifted the economic balance in its favour.

It is these developments that have made the EAD's solar experiment possible; if the Umm al Zamoul facility had to use thermal processes, the number of solar photovoltaic panels required would have made the project prohibitively costly. The authors of the Abu Dhabi master plan suggest that the emirate's immediate gap in demand could be met with small-scale reverse-osmosis plants to desalinate brackish groundwater in Al Ain and Liwa. They acknowledge, however, that "this proposal will run into fierce opposition because of the vested interests that have monopolised water generation in the Gulf region since the 1960s".

Even if reverse osmosis plants use conventional fuels, says Dr Dawoud, they are still more efficient than thermal plants and this fact has led the EAD and others to a potentially revolutionary thought. Originally, power and water were coupled in the name of efficiency, but times have changed. Dr Dawoud and the other authors of the Abu Dhabi master plan argue that even bigger savings will be achieved if the excess heat of electricity generation is used to produce not water, but more power.

But whichever technique is used to produce water, it is vital that the region learns to use it efficiently, says Rob Huehmer, technology leader for desalination at CH2M HILL, a global engineering company. "I am a desalination engineer, so yes, this is what I do for a living, but desalination is only one aspect of sustainable water management," he said. "You need to look at conservation, which has not been a large trend so far."