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Authors: Andrea Atanasovska.
Peer Reviewer: Gül Ozerol.
Water scarcity is one of the most crucial problems in the Middle East and North Africa (MENA) region. The MENA is home to 6.3% of the world population but has only access to 1.4 % of the fresh renewable water resources . The World Bank estimates that by 2050 the annual water demand gap will increase from 42 km3 to approximately 200 km3 . Main reasons for the water scarcity in the region include the increase in population and economic development as well as climate change and desertification.
To mitigate water scarcity, the countries of the MENA region have substantially increased their investment and participation in desalination. There is no single model for desalination, nor can one model be applied in all the countries. The diversity in economic, environmental and social development between the countries has forced a different approach to desalination from each country.
Desalination is not a new technology; on the contrary it is one of the oldest methods of water purification known to man. The desalination process in nature is responsible for what we know as the “water cycle”. The sun provides energy that causes surface water to evaporate. Subsequently the water vapor comes in touch with a cooler air; it then re-condenses to form rain. This process can be duplicated artificially with much faster speed and higher quantity . The process of desalinating salt or brackish water can be done in three ways :
Seawater is distilled through heating, causing it to evaporate. The vapor is then condensed by using electricity or low-pressure vessels to lower the amount of energy required.
The process of reverse osmosis is applied, in which high pressure pumps force the water through a membrane that is impermeable to salt. Electric current is utilized to separate the water and salt.
Status of desalination works in the MENA region
Desalination projects can have a substantially negative impact on the environment, such as marine life disturbance and destruction, greenhouse gas emissions and the decline of the coastal water quality. That is mainly due to the massive consumption of energy during the desalination process, as well as the high concentration of chemical discharges that contain heavy metals from corrosion and low levels of heavy metals. In the reverse osmosis plants, there would be even traces of iron, nickel and chromium .
The relationship between desalination and climate change is a rather complex one. As the desert areas become larger and the population keeps expanding, it can be expected that desalination will remain the predominant choice for increasing freshwater supplies, thus the fossil fuels burned for desalination process and the resulting gas emissions will increase. Furthermore, the desalination process is a very expensive undertaking for the countries concerned. Nevertheless, there are already more than 2,800 desalination plants operating in the MENA region and they produce around 27 million m³ of freshwater from seawater per day .
As mentioned before, there is no single desalination model that can be applied to all the countries in the MENA region. Major issues that countries face regarding desalination include the following:
The quality of the seawater is crucial for the desalination process. For example water from the Persian Gulf , even though is more common, would be more difficult to process than water coming from the Red Sea, due to the limited ability to absorb high-temperatures of brine discharge and the difference that the high levels of salinity will have on the sensitive species of plants and animals .
The size of the desalination plants can be crucial for energy and cost reduction. Larger plants can produce more water by using less resource than the smaller plants (economies of scale). The biggest desalination plant was opened in Algeria in 2014 and has the capacity to produce 500,000 m³ freshwater per day . Depending on the water quality required, different processes of desalination need to take place. The quality standards differ among the uses of water for irrigation, industry, cooking and drinking .
Solar-powered desalination plants
Due to the environmental impacts that are mentioned before, a new and more sustainable approach might be an interesting option for the MENA region. For now the most popular method that will replace the old-fashioned energy consumptive desalination processes is the Concentrated Solar Power Plant (CSP). Other methods of desalination using renewable energy include solar-thermal energy and wind-based energy . CSP works by utilising large mirrors, which are placed in a field, capturing rays of sunlight and reflecting them to the receiver elements and that then amplifies the heat by up to 100 times. This can be used in a thermal power cycle through steam turbines or gas turbines. CSP plants can also function through fossil fuels, allowing them to satisfy the demand.
The biggest consumers of the CSP plants in the MENA region are Algeria, Libya, Qatar, Saudi Arabia, Kuwait and UAE. The United Arab Emirates and China have signed an agreement to cooperate to increase the use of renewable energy in the desalination process. The goal is to reduce the energy consumption to 40%.
CSP is a viable and suitable option for the industrial-scale desalination plants which require more electricity and the high temperature fluids. The MENA region is more than adequate for techniques using solar energy since there is abundance of potential. According to the Middle East Solar Industry Association, in 2014 a record number of solar projects with combined capacity of 294 MW have been awarded in the Middle East. This type of desalination is Eco-friendly and can be perceived as a stable energy provider.
Several other countries in the region such as Egypt, Morocco and Tunisia have started large projects concerning the CSP plants. One of the projects is a series of solar farms expanding through the region. Morocco has the potential to be a leader in the region with the construction of the massive solar energy plant in Ouarzazate which will partially be used for desalination purposes. This project is under the umbrella of Desertec, together with the construction of the Tunisia’s TuNur solar plant, which was approved in 2012. The most recent project took place in Qatar where Monson Group announced new low-energy consumption, automated, renewable energy-powered desalination plant.
Given the rapid expansion of the population, urbanization and of climate change, the countries in the MENA region will rely further on desalination as a way to meet the increasing freshwater demands. Due to the hazardous effect that desalination has on the environment, as well as the high costs of building and utilizing the desalination plants, more sustainable solutions such as CSP are likely to be a promising solution for many countries in the MENA region.
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