x Abu Dhabi, UAEThursday 18 January 2018

Fujairah desalination plant to set standard for energy efficiency

A new desalination plant to be built on the shores of Fujairah over the next two-and-a-half years will aim to set a record for energy efficiency in the region.

A desalination plant to be built on the shores of Fujairah over the next two-and-a-half years will aim to set a new standard for energy efficiency in the region.

The plant, part of an extension to the Fujairah F1 Independent Water and Power Plant in Al Qidfa, aims to achieve a specific energy consumption of 3.7 kilowatt hours for every cubic metre of water produced.

"This is a record for the Gulf region," said Jesus Sancho, Middle East regional director of Acciona Agua, the company leading the consortium, which earlier this month won the contract to design and build the facility.

Typically, projects in the region have requirements of between four and six kilowatt hours per cubic metre, said Dr Corrado Sommariva, Managing Director Generation at ILF Consulting Engineers in Abu Dhabi.

"This project is really setting a new benchmark for energy efficiency," said Dr Sommariva, whose company acted as technical adviser to the project, liaising between the Spanish consortium and the project's owner.

"It is very rare for projects here to go below the four kilowatt hour per cubic metre mark," said Dr Sommariva, who is also president of the International Desalination Association.

The plant will have a capacity of 137,000 cubic metres of drinking water per day. It will be built within the premises of the existing Fujairah F1 plant, which already produces 455,000 cubic metres of water per day.

The facility is owned by Emirates Sembcorp Water & Power, a company founded by the Abu Dhabi Water and Electricity Authority in partnership with Singapore's Sembcorp Industries. Once completed in 2015, the new plant will sell water to the Government at a price per cubic metre which is among the lowest in the Gulf.

The UAE produces more than 90 per cent of its potable water through desalination, which is an energy-intensive process. Mr Sancho said that reducing the energy requirement of the plant required designers to use the latest technologies such as pressure centre and energy recovery systems.

The plant will rely on reverse osmosis, a process in which seawater at pressures as high as 70 bar – equivalent to the pressure 700 metres below the surface of the ocean – is pumped through a series of membranes. The designers behind the new plant will be aiming to cut energy consumption by installing fewer but larger water pumps.

Once the water goes through the membranes, the residual high-pressure will be captured by special rotary devices. The generated energy will be redirected to the water pumping system, lowering the overall energy requirements of the process.

The plant will also gain efficiency by using the seawater outflow of the larger adjacent thermal desalination plant already in operation. This is the first time this concept is being introduced on such a large scale, said Dr Sommariva. It means the new plant will need less fresh seawater.

"Compared to a normal plant, the seawater consumption will be very small," he said.

The decision to recycle the outflow of the thermal plant means less energy will be needed to pump water to feed the new facility.

As the larger plant relies on thermal processes, essentially distilling seawater to separate the salt out of it, its warm outflow increases the productivity of the membranes involved in the reverse osmosis process.

Most importantly, the decision also meant no new infrastructure was needed to provide additional seawater, saving money and avoiding the environmental impacts associated with marine works. It also saved the time usually needed to obtain permits for such work.

"This plant is a demonstration that being efficient is also cost-effective," said Dr Sommariva. "Through innovations like these, a lot of energy can be saved in this part of the world."

Acciona Agua is also building a pre-treatment facility where seawater intake, to be used by both the new and the existing plants, will be treated to remove algae and other organic pollutants. Construction is set to start by the end of March