As water scarcity and the climate crisis worsen, solar energy will become the ultimate solution to sustainability. The Middle East should play a leading role as a solar energy superpower. 
In the past few years, we unwillingly witnessed previously unfathomable water rationing in Cape Town, South Africa, Sydney, Australia, and Chennai, India. The term “day-zero”, which was first used in Cape Town, indicates how easily human society can be pushed into a primitive living state when the water supply is not secure. 

While rapid population growth and steadily improving living standards, among others, continue to put enormous pressure on already very stressed water systems, climate change is increasing air temperatures along with the frequency and intensity of extreme droughts, which together lead to increased water use for crop irrigation and livestock. Predictions indicate that more than 60 percent of the world’s population could experience severe water scarcity by 2040. Ensuring water security is a daunting challenge and, in many countries, tantamount to national security. 

Desalination of seawater, an energy-intensive process, provides water to many parts of the globe. The Middle East, with limited freshwater sources, is heavily dependent on desalination. It accounts for 45 percent of the world’s total seawater desalination capacity. Consequently, water and energy are closely intertwined in the Middle East. In Saudi Arabia, around 10 percent of the electricity is used for seawater desalination. In Abu Dhabi, the desalination sector contributes more than 22 percent of the emirate’s total CO2 emissions. Climate change is already leading to environmental changes in our seas and oceans. Phytoplankton productivity may be a casualty of climate change, which may increase the energy intensity of seawater desalination processes. 

Water, energy and the climate are inextricably interconnected in the Middle East and beyond. Solar energy must sit at the center of this nexus for the following four reasons.

First, solar energy is clean with a minimal carbon footprint. Studies have projected life-cycle emissions from solar power to be 4–12 gCO2eq/kWh (note: grams of CO2 equivalent per kilowatt hour electricity generated), compared with 80–110 and 400–1000 gCO2eq/kWh of fossil fuel burning plants with and without carbon capture and sequestration, respectively.1 

More often than not, the complaint against solar energy is for its low areal energy intensity, which necessitates the use of large land areas in any form of its utilisation. However, Japan is third in the world in total photovoltaics (PV) installation capacity and Singapore is on its way to producing 4 percent of its total electricity from solar energy by 2030. These two land-scarce countries should inspire the rest of the world. Our will and determination can always overcome physical land constraints.

Second, solar energy is abundantly available in most parts of the world where there are human activities. The often-quoted statement that the solar energy that the Earth receives in one single hour is enough to power the entire world for one year communicates the vast abundance of solar energy available for energy production and its unmatched potential.

Third, solar power has a very low barrier-of-entry, which is especially true with PV. The cost of PV has been drastically reduced. Depending on available capital, PV can be used at any scale, from household panels to massive industrial-scale solar farms. Nowadays, regular households can afford small-scale PV systems even without governmental subsidies. Affordability leads to a virtuous cycle in PV development. A very recent study reports that the cost of solar power is lower than local grid power in 344 cities in China, even without subsidies. And in 76 of those cities, the price of solar power was equal to or less than that of coal-fired power.2 

Fourth, solar power generation consumes minimal amounts of water. To generate 1 MWh of electricity, PV consumes only 2 gallons of water whereas thermal power plants using coal and nuclear fuel as energy sources consume 692 and 572 gallons of water, respectively.3  Technologies now being developed can even turn conventional PV farms into net freshwater production facilities while also producing electricity.4  

The Middle East is blessed with stable and reliable solar irradiation; arguably, it is the best quality solar irradiation in the world. In addition, there are vast areas of land in the Middle East that remain undeveloped and unused. The annual average solar irradiance in Saudi Arabia (2300 kWh/m2) is more than 1.4 times that in Japan (1600 kWh/m2). By a simple calculation, if 5  percent of the land area in Saudi Arabia were covered with state-of-the-art PV panels, more electricity than needed by the entire world could be produced. However, solar energy has been considerably underutilised in the Middle East. At status quo, solar electricity in Saudi Arabia and the United Arab Emirates accounts for less than 0.1 percent and 1 percent of the total domestic electricity generation, respectively.

Fortunately, giant solar projects in both Saudi Arabia and the United Arab Emirates currently being planned demonstrate the region’s ambitions to rightfully lead the world in solar power generation. 
As the world is moving into a decarbonised and circular economy, solar energy must sit at the center of the water-energy-climate nexus. 


1. Pehl, M.;  Arvesen, A.;  Humpenöder, F.;  Popp, A.;  Hertwich, E. G.; Luderer, G., Understanding future emissions from low-carbon power systems by integration of life-cycle assessment and integrated energy modelling. Nature Energy 2017, 2 (12), 939.
2. China brings solar home. Nature Energy 2019, 4 (8), 623-623.
3. Wilson, W.;  Leipzig, T.; Griffiths-Sattenspiel, B., Burning our rivers: The water footprint of electricity. River Network (Austin, TX: Comptroller of Public Accounts, Data Division Services) Publication 2012,  (96-1704), 62.
4. Wang, W.;  Shi, Y.;  Zhang, C.;  Hong, S.;  Shi, L.;  Chang, J.;  Li, R.;  Jin, Y.;  Ong, C.; Zhuo, S., Simultaneous production of fresh water and electricity via multistage solar photovoltaic membrane distillation. Nature communications 2019, 10 (1), 1-9.

By Professor Peng Wang / King Abdullah University of Science and Technology The Hong Kong Polytechnic University

As water scarcity and the climate crisis worsen, solar energy will become the ultimate solution to sustainability. The Middle East should play a leading role as a solar energy superpower. 
In the past few years, we unwillingly witnessed previously unfathomable water rationing in Cape Town, South Africa, Sydney, Australia, and Chennai, India. The term “day-zero”, which was first used in Cape Town, indicates how easily human society can be pushed into a primitive living state when the water supply is not secure. 

While rapid population growth and steadily improving living standards, among others, continue to put enormous pressure on already very stressed water systems, climate change is increasing air temperatures along with the frequency and intensity of extreme droughts, which together lead to increased water use for crop irrigation and livestock. Predictions indicate that more than 60 percent of the world’s population could experience severe water scarcity by 2040. Ensuring water security is a daunting challenge and, in many countries, tantamount to national security. 

Desalination of seawater, an energy-intensive process, provides water to many parts of the globe. The Middle East, with limited freshwater sources, is heavily dependent on desalination. It accounts for 45 percent of the world’s total seawater desalination capacity. Consequently, water and energy are closely intertwined in the Middle East. In Saudi Arabia, around 10 percent of the electricity is used for seawater desalination. In Abu Dhabi, the desalination sector contributes more than 22 percent of the emirate’s total CO2 emissions. Climate change is already leading to environmental changes in our seas and oceans. Phytoplankton productivity may be a casualty of climate change, which may increase the energy intensity of seawater desalination processes. 

Water, energy and the climate are inextricably interconnected in the Middle East and beyond. Solar energy must sit at the center of this nexus for the following four reasons.

First, solar energy is clean with a minimal carbon footprint. Studies have projected life-cycle emissions from solar power to be 4–12 gCO2eq/kWh (note: grams of CO2 equivalent per kilowatt hour electricity generated), compared with 80–110 and 400–1000 gCO2eq/kWh of fossil fuel burning plants with and without carbon capture and sequestration, respectively.1 

More often than not, the complaint against solar energy is for its low areal energy intensity, which necessitates the use of large land areas in any form of its utilisation. However, Japan is third in the world in total photovoltaics (PV) installation capacity and Singapore is on its way to producing 4 percent of its total electricity from solar energy by 2030. These two land-scarce countries should inspire the rest of the world. Our will and determination can always overcome physical land constraints.

Second, solar energy is abundantly available in most parts of the world where there are human activities. The often-quoted statement that the solar energy that the Earth receives in one single hour is enough to power the entire world for one year communicates the vast abundance of solar energy available for energy production and its unmatched potential.

Third, solar power has a very low barrier-of-entry, which is especially true with PV. The cost of PV has been drastically reduced. Depending on available capital, PV can be used at any scale, from household panels to massive industrial-scale solar farms. Nowadays, regular households can afford small-scale PV systems even without governmental subsidies. Affordability leads to a virtuous cycle in PV development. A very recent study reports that the cost of solar power is lower than local grid power in 344 cities in China, even without subsidies. And in 76 of those cities, the price of solar power was equal to or less than that of coal-fired power.2 

Fourth, solar power generation consumes minimal amounts of water. To generate 1 MWh of electricity, PV consumes only 2 gallons of water whereas thermal power plants using coal and nuclear fuel as energy sources consume 692 and 572 gallons of water, respectively.3  Technologies now being developed can even turn conventional PV farms into net freshwater production facilities while also producing electricity.4  

The Middle East is blessed with stable and reliable solar irradiation; arguably, it is the best quality solar irradiation in the world. In addition, there are vast areas of land in the Middle East that remain undeveloped and unused. The annual average solar irradiance in Saudi Arabia (2300 kWh/m2) is more than 1.4 times that in Japan (1600 kWh/m2). By a simple calculation, if 5  percent of the land area in Saudi Arabia were covered with state-of-the-art PV panels, more electricity than needed by the entire world could be produced. However, solar energy has been considerably underutilised in the Middle East. At status quo, solar electricity in Saudi Arabia and the United Arab Emirates accounts for less than 0.1 percent and 1 percent of the total domestic electricity generation, respectively.

Fortunately, giant solar projects in both Saudi Arabia and the United Arab Emirates currently being planned demonstrate the region’s ambitions to rightfully lead the world in solar power generation. 
As the world is moving into a decarbonised and circular economy, solar energy must sit at the center of the water-energy-climate nexus. 


1. Pehl, M.;  Arvesen, A.;  Humpenöder, F.;  Popp, A.;  Hertwich, E. G.; Luderer, G., Understanding future emissions from low-carbon power systems by integration of life-cycle assessment and integrated energy modelling. Nature Energy 2017, 2 (12), 939.
2. China brings solar home. Nature Energy 2019, 4 (8), 623-623.
3. Wilson, W.;  Leipzig, T.; Griffiths-Sattenspiel, B., Burning our rivers: The water footprint of electricity. River Network (Austin, TX: Comptroller of Public Accounts, Data Division Services) Publication 2012,  (96-1704), 62.
4. Wang, W.;  Shi, Y.;  Zhang, C.;  Hong, S.;  Shi, L.;  Chang, J.;  Li, R.;  Jin, Y.;  Ong, C.; Zhuo, S., Simultaneous production of fresh water and electricity via multistage solar photovoltaic membrane distillation. Nature communications 2019, 10 (1), 1-9.

By Professor Peng Wang / King Abdullah University of Science and Technology The Hong Kong Polytechnic University

The promise of smart cities of the future is enormous – congestion, pollution, overcrowded transit, wasted energy, delayed emergency response all problems of the past. With smart cities, and I shall use this term as moniker that sums up the digitisation of analog processes, big data, the internet of things, automation, machine learning, neural nets, artificial intelligence – almost anything seems to be within the realm of possibility. 

Smart city decision makers will have access to oodles of data to base their decisions on, and better yet decision making will be made even easier as all options will be presented having been thoroughly analysed by sophisticated systems.

But do we know if these sophisticated systems are really giving us the best option?  I am astonished by the inability to often understand how AI come up with their recommendations or actions at times. When AlphaGo beat Lee Sodol, the machine developed a strategy that baffled the world of Go, a game that humans played for over two millennia. We can analyse and try to understand but how it arrived at it its conclusion is not clear. Recently, in one of our on-going research projects, I asked the creators of the AI how it learned to read a satellite images and create mapping at scale? The response was “we don’t really know happens inside”. What we do know is that the AI is able to take our training material and create data at a scale, accuracy and speed that is unrivalled by humans.

AIs are very good at taking rules and playing by them. Clearly defined problems, that can be packed into an algorithm, will yield results at greater speed and higher levels of accuracy than can be produced by humans. Most importantly this releases us from trivial and mundane tasks to turn our hands to something potentially more interesting and meaningful.

Herein however lies the machine’s (current) biggest weakness when we think of the promise of smart cities. Cities are inherently messy, with the rules changing all the time. Messy as they all differ from one another in climate, politics, economics, social norms, size and so on. Messy as they are constantly changing and evolving, over the span of a day, a week, a decade, often in patterns we can only hope to recognise in hindsight. And most importantly, messy as they are made up hundreds of thousands, if not millions of humans, and all with their own individual quirks, personalities, moods and irrationalities. 

When it now comes to making decisions over what is the best trajectory any one city should follow, we must recognise that we cannot possibly feed a machine all possible eventualities that will allow it to make the right choice.

For example, we often discuss the value of green spaces and vegetation in the cities of the Gulf. On one hand there is no way that it can be sustainable to grow grass and trees in the desert based on the amount of resources required to ensure their survival in the harsh climatic conditions. On the other hand, how do we measure the joys of people using these spaces with their friends and families? Whilst we know of the benefits of biophilia, how do we place a value on it? I use a rule of thumb, asking myself if I would let one of my children run around without supervision on a piece of grass, then the effort expanded is ok. Consequently, on a landscaped highway junction, it is not.

We humans have 6,000 years of experience in making cities, and we must build on this. Modern city making professions have their origins in mass urbanisation that the north-Atlantic world experienced during the first industrial revolution and the resulting squalor of cities in the 19th century. Modern architecture, public health professions etc. all stem from a desire to improve the cities for its residents. The last 100 or so years we have sought salvation in designing cities for the car now turning to another technology to help us resolve the problems this caused.

In the cities of the 21st century however, what are the issues that we truly must resolve? Sustainability, inclusivity and well-being are at the top of my list. We humans must remain aware of the pitfalls that technological innovation can harbour amongst all its benefits. For all its benefits, social media has also contributed to isolation and reduced the need for human interaction. Other smart city technology, whilst deployed with the best intention, might have unintended negative consequences. 

I believe that for smart cities of the future to meet their promise, a collaboration between all the technological possibilities and a human effort in making sense of it all, will be fundamental.

By Hrvoje Cindric / Associate, Planning, ARUP