06 JAN 2018
Desalination 2.0: the solution to water scarcity?
Water scarcity is a global challenge. A growing population, which is expected to increase from around 7.5 billion today to nearly 10 billion by 2050, according to a forecast by the United Nations (UN), is putting growing pressure on a finite supply of water. Global demand for water is expected to increase by 55% by 2050. Within the next decade, two thirds of the world’s population could be living in “water stressed” countries.
Regions affected won’t be limited to arid regions, such as Sub-Saharan Africa and the Gulf States in the Middle East. The strain on the water supply will be particularly acute in cities. The number of people living in cities is expected to rise from about 55% in 2016 to 66% by 2050, according to the UN. This population increase could cause major disruption to cities if suitable water technologies are not in place to serve demand. In the United Arab Emirates (UAE) − one of the most arid parts of the world with little rainfall − groundwater levels are low and in steady decline. What groundwater there is, is typically very salty (saline). For the UAE and about 150 other countries on or near the coastline, with minimal rainfall and little freshwater, there is currently little choice but to rely on desalination technology. Desalination involves pumping and processing sea water to remove excess salt and other minerals to obtain fresh water suitable for human consumption or irrigation. The technology is already widely used, with more than 300 million people relying on desalinated water for some or all their daily needs, according to the International Desalination Association.
Desalination has been vital for the UAE’s rapid growth and development. The country gets 96% of its domestic water through desalination. Two of the big disadvantages of desalination technology are closely linked to each other – firstly, desalination is energy intensive, and secondly these energy needs have historically been met by fossil fuels. In the UAE, seawater desalination needs about 10 times more energy than surface, freshwater production. In the Gulf region alone, desalination plants account for 0.2% of the entire world’s electricity consumption. However, these challenges are now being addressed and desalination technology is expected to play a key role in serving growing demand for fresh water. Energy accounts for around 70% of the cost of desalination and is typically derived from fossil fuels. By reducing energy intensity and running desalination plants on renewable energy, operators could both reduce their operating costs and minimise their carbon footprint.
In the UAE, Abu Dhabi Future Energy Company (Masdar) has piloted five energy-efficient seawater desalination projects at a testing facility on the Ghantoot coast. The long-term goal is to implement renewable energy-powered desalination plants in the United Arab Emirates, as well as the wider region, and to have a commercial scale facility operating by 2020. Once rolled out, this project is likely to have implications well beyond the Middle East. Elsewhere, island countries including Japan, Taiwan and South Korea have been using variations of desalination technology, which involve sucking up seawater through long pipes running hundreds of metres out to sea so that they gather water from deep under the ocean’s surface. Water from more than 300 metres deep is purer and has more nutrients, making desalination simpler and cheaper because less energy is required to process the seawater.
Desalination technology has played a key role in helping the UAE and other countries in water scarce regions grow their cities and industries. Over the next decades, desalination will also be vital in helping emerging economies develop, although how these countries power their plants will be different. Desalination, when combined with renewable energy and potentially energy storage, will significantly improve the economic viability of processing sea water and make it more environmentally sustainable. This will play a critical role in responding to the growing global challenge of water scarcity.