This is a previous project site under CGIAR Research Program on Water, Land and Ecosystems (WLE). For more information and current updates, visit the WLE website.

Home > Basin > Mekong > Water, Food and Energy: A back-of-envelope analysis

As we sail down the road from Phnom Penh to Sihanoukville in air-conditioned luxury, we can stare out of the mirrored windows at mile upon mile of dry rice paddy. It is the dry season, and the landscape is a dark brown, the paddies empty. On the back of the car is a sticker proclaiming the custom-made in-car sound system, which belts out Yol Aularong’s classic ‘Cyclo’ from the Royalist pre-Khmer Rouge days of King Norodom.

My driver is a ‘bong tom’, a ‘big brother’, with a day job in a Cambodian ministry, a side job in the military, and a sluice of other business activities on the side. He is much wealthier than I am, and the car we’re in is the bong tom trademark, a Lexus GX SUV, with a 4.6 litre, V8 engine, painted in high-gloss black. Inside the car, the air conditioner has pushed the temperature down to a chilly 20 degrees. Outside it, a man in a conical hat walks alongside a pair of buffalo. The blades on the plough they’re pulling scratches at the hard earth.

The Lexus is not a nexus. Or so I thought. But in December 2011, when we held our first Mekong Forum on Water, Food and Energy (W-F-E) in Phnom Penh, Cambodia, our hosts stared at the term we were trying to introduce to them. Nexus. One of them finally had the courage to stand up and ask whether or not a ‘nexus’ was anything like a ‘Lexus’. The participants in the room laughed, and I smiled. But let’s think about that for a moment. Ninety-seven litres of water are needed to produce a litre of the unleaded petrol that the Lexus GX favours[1]. The Lexus GX I’m in uses a litre of petrol to drive a rather paltry 3 km, and he needs 62 litres to get to Sihanoukville, or almost 6,000 litres of water.

Let’s extrapolate. The average American drives 21,687 km per year[2]. Let’s assume too that average fuel consumption in the US is 0.126 litres of petrol per 100 km[3]; that means that the average American uses 2,732 litres of fuel per car, per year, or 265,000 litres of water. In 2010, there were an estimated 1.015 billion cars in the world[4], using 2.8 billion litres of fuel per year, fuel that needed 269 cubic kilometres of water to produce. About 15 trillion swimming pools[5]. I know it’s very back of the envelope. I know that most of the world’s car owners don’t drive as far as the average American, and possibly don’t score the same fuel efficiencies as Americans, and that there’s huge variations all over the place, and that the figures I’ve used above are for fossil fuel (and not biofuel, which needs much more water). But it all does make you think, doesn’t it?

More robust analyses, however, reveal the staggering amount of water needed to produce energy. In the US, leaving a 60-watt light bulb on for an hour uses five litres of water[6]. Fossil-fuel-fired thermoelectric power plants consume more than half a km3 of fresh water a day. The average American home uses 1,000 kWh of electricity per year, which requires about 95,000 litres of water to produce[7]. In 2009, total worldwide energy consumption was 141,304 TWh[8].  In 2005, the world needed 18.156 km3 of water specifically for energy production[9]. By 2050, we’ll need 20.3 km3 fresh water for energy production[10].

But what of the man with the plough, and his buffalo that we hurtled past just back there? He and tens of thousand of other farmers around the globe are also major water users. The FAO reckons that there are about 43,000 km3 of ‘internal renewable water resources’ (i.e. internal river flows and groundwater from rainfall)[11]. Most of this escapes human attention, and is used by the environment, or directed back into the water cycle. Presently, some 7,130 km3 are captured for food production[12]. The estimated 9.1 billion people that will be living on earth in 2050 will require some 70% more food than we presently produce, requiring 70-90% more water, or between 12,050–13,500 km3 in total, depending on actual population growth, and a variety of assumptions[13]. At the same time, non-agricultural (domestic and industrial uses) uses will more than double from around 523 km3 in 2000, to 1,298 km3 in 2050[14].

So, the question arises: what if the farmer in the conical hat wants to become like the bong tom in his Lexus? No reason why not. Every development initiative on earth is trying to help poor people (whether farmers or otherwise) improve their lives, and every poor person naturally aspires for a better life. But what does that mean? A ‘better life’? Arguably, a better life means owning a Lexus, and while this fine piece of Japanese automotive engineering might be a good metaphor for the water-food-energy nexus, it’s also a pretty good metaphor for development. With global corporations hugely influential in defining development paths and trajectories, it is only reasonable that the Toyota Corporation should want every man, woman and child on earth to own a Lexus GX. In this sense, development is being equated with increased consumption. Combine that with increasing populations, consumption patterns in the future will use more water, require more food, and generate more waste than at any other time in human history. Hence why the Stockholm Environment Institute refers to our present epoch as the ‘anthropocene’[15].

And as cities grow, and more people buy more Lexus SVUs (would that be ‘Lexi’?) and require more food, an immense tension begins to emerge between water needs for food and water needs for energy. And that, essentially, is what the whole water-food-energy Lexus…I mean, nexus, is all about.

Now, how do we address it? Necessity is nearly always the mother of invention, so one could argue that people will adapt – rising oil prices have prompted a new generation of hybrid cars, after all.  If, like me, you’re a believer in complex adaptive systems, however, small initiatives all over the world eventually begin to coalesce into one monumental change.

At next week’s Stockholm World Water Week, we’ll be launching one initiative. It focuses on the Mekong, Congo, Amazon, Ganga and Nile River Basins, and more particularly on dams. Globally, more than 40,000 large (i.e. ≥ 15 metres in height) dams barrage the world’s rivers, of which 300 are considered ‘major’ dams. Most large dams (9,265) are located in the USA, followed by China (5,191) and India (5,101). The US has 50 of the world’s major dams.

Against a backdrop of changing climates, dams have considerable potential for storing water, and for contributing to agriculture. Yet, over 71% of the world’s dams are for single purpose only (50% for irrigation, 18% for hydropower). What matters about dams is where they’re placed (it’s always the lowest one in a reach that matters for the system as a whole), and their cumulative impact. The world’s reservoirs contain some 15,500 km3 of water – more than twice the water used in agriculture globally – and cover an area of about 500,000 km2. This represents about 0.3% of the world’s land surface area – about the size of Spain.

Combined, dams, and the water they retain, the environments they affect, and the people that they affect, are massive. I think the changes that will emerge because of dams are considerable, significant, and potentially dreadful. But let’s face it, dams drive economies and, for poor countries, electricity is a progenitor of development, and irrigation can send agricultural production into the stratosphere.

The Initiative on Sustainable Dams and Development (ISDD), which will be launched at World Water Week, is a modest first step to bring these contrasts – between energy and water, food and water, food and energy – into a global dialogue, to uncover ideas, and pursue them until we have solutions to the tensions that characterise this Lexus.


By Kim Geheb, CPWF-Mekong Basin Leader

[2] According to the US Federal Highway Administration.

[3] See ‘Project Amercia’ here.

[4] According to research by Ward’s Auto.

[5] The average Texan swimming pool requires about 19 m3 to fill.



1 Comment

  1. John says:

    And every one of those delegates laughing about the Lexus probably had one.
    And every one, wealthier than you, thanks to all the money being dropped on them.
    Seriously, this is the problem in Cambodia.
    Created by the big aid organisations.