Renewable Energy Powers Desalination Plants: Kill Two Birds With One Stone

Renewable Energy Powers Desalination Plants: New Solution to an Old Crisis 

Growing water demand due to rising population, altered standards of living, industrialization, climate change, and wasteful water management policies, is resulting in substantial water shortage and scarcity. While developing countries are hardest hit by water shortage, developed countries are beginning to face the issue as well. 

According to the United Nations World Water Development Report 2019, water use has increased by about 1% per year since the 1980s, over 2 billion people live in countries experiencing high water stress, and twice that size experience severe water scarcity during at least one month of the year. Needless to say, as demand for water grows, the stress levels continue to increase. 

Traditionally, freshwater has been obtained from various sources including lakes, rivers, and aquifers. With increasing the need for freshwater, these water sources are being taxed more and more, often to the point where the price of safe drinking water in the low-income communities is exhaustively higher compared to tapped municipal drinking water; for instance in some parts of rural India the cost of water is roughly 40 times the cost of municipal drinking water available a few miles away in a nearby city. This is a clear help alert to create a sustainable solution to the rural water problem and the global water crisis.

For the last 50-60 years, modern engineering has gifted us with substantially improved desalination techniques that can produce water efficiently and economically. Seawater desalination literally opens up the OCEANS as essentially unlimited and renewable source of freshwater. As of 2013, there are nearly 75 million cubic meters per day of installed desalination capacity around the world. These plants treat a broad range of waters including seawater, river water, groundwater, and others. The major challenges to implement these technologies are, however, making them low-cost, community-scale and relatively maintenance-free design. Then again, huge energy and material requirements are some other drawbacks of these plants. Therefore, the solution for the global water crisis should, hence, be implementable within these constraints too.

Many desalination plants still consume a lot of fossil fuels for heat energy production in thermal distillation plants and electricity requirement in membrane desalination systems. Nowadays, however, research activities are geared towards renewable energy powered desalination technologies such as solar and geothermal powered desalination systems in particular. This technology conserves conventional fossil energy, decreases environmental degradation, and ensures that free natural energy resources are tapped and pure water is continuously produced with low maintenance needs. Overcoming the challenges of desalination technologies is entirely possible, and the renewable energy powered desalination technology could be an implementable solution for this old crisis of water, and in the other hand, this technology could pave the way for more cost reduction as well as decline in energy consumption at the future systems with more investigation on the new technologies such as new hybrid desalination systems.

By Mohammad-Reza Kolahi

References:

 [1] Govindan, P.N., 2012. Thermal design of Humidification Dehumidification systems for affordable and small-scale desalination (Doctoral dissertation, Massachusetts Institute of Technology).

 [2] Oki, T. and Kanae, S., 2006. Global hydrological cycles and world water resources. science, 313(5790), pp.1068-1072.

 [3] Smakhtin, V., 2004. Taking into account environmental water requirements in global-scale water resources assessments (Vol. 2). Iwmi.

 [4] WWAP (UNESCO World Water Assessment Programme), 2019. The United Nations world water development report 2019: Leaving no one behind. Paris, UNESCO.

 [5] Mistry, K.H., 2013. Irreversibilities and nonidealities in desalination systems (Doctoral dissertation, Massachusetts Institute of Technology).

 [6] Prahalad, C.K. and Hammond, A., 2002. Serving the world's poor, profitably. Harvard business review, 80(9), pp.48-59.

 [7] Pankratz, T., 2013. IDA desalination yearbook 2012–2013. Media Analytics Ltc: Oxford, UK.

 [8] Giwa, A., Akther, N., Al Housani, A., Haris, S. and Hasan, S.W., 2016. Recent advances in humidification dehumidification (HDH) desalination processes: Improved designs and productivity. Renewable and Sustainable Energy Reviews, 57, pp.929-944.