Oman is struggling to meet water demand despite building desal capacity.
Swathes of northern Oman have been hit by severe water shortages in recent months just as demand began to soar with the arrival of searing summer temperatures.
Local media reported hundreds of thousands of citizens in Muscat, Sohar and Barka provinces being left without water for days on end. Some people were forced to queue for hours to purchase costly supplies delivered by tankers, while shops and supermarkets sold out of bottled water.
The cause of the shortage appears to be a combination of supply and demand factors. Continuous improvement of the ageing water network frequently requires parts of it to be shut down for maintenance. But the problem was made much worse by the untimely unscheduled shutdown of a major desalination plant that serves three Governates.
The 150,000 cubic metre per day (m3/d) Sohar 1 Power and Desalination Plant halted production on May 5 and 19, resulting in a critical interruption of water supply in the North Al Batinah area. An investigation by the Authority for Electricity Regulation (AER) found that the main cause of the incident was a rupture of the seawater supply pipe to the Oman Oil Refineries and Petroleum Industries Company (Orpic) facilities on May 3.
News that the country’s newest desalination plant has begun to crank into gear has therefore come as a welcome relief to weary Omanis. The 191,000 m3/d Muscat City Desalination Plant at Ghubrah has begun trials and will be gradually ramped up over the coming months. However the plant is already running several months behind schedule and is not due to reach full capacity until August at the earliest.
It is expected that the additional volumes supplied by the plant will be able to meet short term water demand in and around the capital city of Muscat. However, with water demand predicted to rise sharply over the next five years, the region still seems set to suffer further water shortfalls despite the addition of huge volumes from several new desalination projects.
Water demand in the northern region, comprising the Interconnected Zone and Sharqiyah Zone, is projected to increase by 6% per year, from 226 million m3 in 2015 to 328 million m3 in 2021, according to figures by Oman Power and Water Procurement Co (OPWP). In the Interconnected Zone, peak water demand is expected to rise by as much as 540,000 m3/d by 2021.
The Interconnected Zone includes the Governorates of Muscat, Al Batinah North, Al Batinah South, Buraymi, Ad Dakhiliyah, and Ad Dhahirah3 and the process water demand of the Sohar Industrial Port area. Existing desalination plants that serve this zone are the old Ghubrah Power and Desalination Plant, Barka I and Barka II Power and Desalination plants, and Sohar I Power and Desalination Plant.
In addition there are a number of projects already under construction that will add significant desalination capacity in the coming years. Barka I will have an extra 57,000 m3/d in the third quarter of this year. The Muscat City Desalination Plant at Ghubrah, with capacity of 191,000 m3/d is also scheduled to come on stream in Q3; A new 200,000 m3/d desalination plant at Qurayyat will begin commercial operation in 2017; The following year will see new desalination plants commissioned at Barka (281,000 m3/d) and Sohar (250,000 m3/d).
Supplies will still be tight
Oman’s expansion plan for water desalination capacity aims to meet peak demand, plus a 14% margin for supply security, OPWP explained in its most recent Seven Year Statement. After an emergency, the water levels in the reservoirs may be low so desalination capacity must be high enough to allow for their replenishment as well as to meet regular demand.
OPWP says supply sources will fall short of capacity targets this year and next. Available capacity is currently insufficient to meet peak demand until the Muscat City IWP begins operation around August. The plant’s 191,000 m3 /d capacity will cover peak demand and most of the capacity target. In 2016, contracted capacity should be sufficient to meet peak demand but not to meet the target reserve margin.
From 2017 to 2019, the new capacity that will come on stream at Qurayyat, Barka and Sohar should be sufficient to meet targets despite retirement of the old Ghubrah units and contract expiration at Barka I, though there may be a slight deficit in 2017, OPWP says. Then in 2020, a deficit in reserves could again emerge in a high demand scenario.
Negotiations are ongoing to extend the Barka I contract while procurement of a new 300,000 m3/d IWP by 2021 is under consideration. The new plant would be sufficient to cover several years of demand growth, says OPWP. Procurement activities would begin around 2017 to allow several years to assess demand growth and contractual developments at existing plants before committing to the capacity requirement. Several potential sites are under evaluation.
Reverse Osmosis is taking over
Due to its higher level of cost and energy efficiency, reverse osmosis (RO) technology is expected to win an increasing share of desalination capacity while existing thermal desalination units will be gradually retired or shifted to standby mode.
For all new plants, OPWP is considering the opportunity for combining power generation with water desalination so as to benefit from economies of co-location and co-procurement. The most recent examples of combined development of power and desalination capacity are the Salalah IWPP in Dhofar and the Barka II Power and Desalination Plant in the main interconnected system. In both cases, bidders proposed to use RO rather than thermal technology, although the tender did not specify the technology to be used.
For current major procurement projects – IWPs at Barka and Sohar – OPWP considered combining the projects at a single site at Suwaiq as well as other locations. However, land constraints at the selected sites, particularly with respect to access corridors needed for electricity, water, and gas transmission, prevented combined power and water development within the required timeframe.