x Abu Dhabi, UAEFriday 21 July 2017

Renewable energies should drive desalination, Abu Dhabi event told

In the UAE, where more than 90 per cent of potable water is desalinated, solar power would greatly reduce the carbon footprint.

ABU DHABI // Countries in the region should consider powering desalination plants with solar and other renewable forms of energy to combat rising prices of fossil fuels and growing needs for potable water, say experts.

"Oil and gas are limited resources ... we have to find another solution, we have to find another source," said Dr Mohammed Dawoud, water-resources manager at the Environment Agency - Abu Dhabi (EAD).

"So it is very important for GCC countries, for all countries in the world, to invest more and to focus on research and development in the field of renewable energy."

Dr Dawoud was addressing an expert audience at the Solar Desalination Forum at Le Royal Meridien hotel in the capital. The event finishes today.

With scarce fresh water resources, Arabian Gulf countries rely on desalination - an energy-intensive process that removes the salts dissolved in sea water - to produce potable water. The UAE, for example, relies on desalination plants for more than 90 per cent of its potable water needs. Using solar power for the process would reduce the country's carbon footprint.

Still, the experts agreed that there were a number of challenges to be met before desalination plants could rely on renewable power as a mainstream solution.

"The capital cost is still high, and we are now looking to improve the cost of solar panels. By improving their efficiency in the future, this will dramatically decrease the cost," Dr Dawoud said.

His comments refer to the agency's experience of running 30 small-scale desalination plants in Abu Dhabi since 2009. The plants provide water at remote wildlife reserves in the western and eastern ends of the emirate. The water is used for limited irrigation and to support wildlife as well as by a number of people who work at the reserves.

Each system has a capacity to produce about 60 cubic metres of water a day. The plants rely on groundwater, with a salinity of about 35,000ppm (parts per million) - a little less than local sea water - as a source for the desalination process. Each plant has an array of solar photovoltaic panels to produce the electricity necessary to pump groundwater to the surface and then pressurise it and run it through a special membrane capable of removing most of the dissolved salts.

EAD has used the data collected during the operation of the plants to compare the cost of the water they produce with the cost of producing water in the emirate's conventional plants. Besides relying on traditional and cheaper sources of power, such plants have huge capacities, which reduces costs per unit of production.

Last year, production costs varied between Dh5.51 and Dh8.45 per cubic metre in utility plants. But the water produced by EAD's small-scale solar desalination units costs between Dh13.59 and Dh15.43, Dr Dawoud said. The main cost was associated with the solar panels needed to provide electricity for the systems, he said.

Hassan El Banna Fath, professor of practice at the Masdar Institute of Science and Technology, said that another issue was the need to provide continuous power to run desalination plants. Unless investments are made in storage capacity, solar panels can produce electricity only during the day.

"The challenge lies in integrating a transient system with a non-transient system," he said.

Another issue has to do with improving the efficiency of the existing desalination technologies or opting for new ones. This would indirectly cut plants' energy requirements.

Earlier this year, Masdar announced it was doing just that. Masdar said it was looking for technology companies to partner with in three trial projects, which would run until the end of 2015. The aim is to build by 2020 a large-scale, commercially viable water-desalination plant powered by renewable energy.

vtodorova@thenational.ae