The water energy food nexus – challenges and emerging solutions

Abstract

Water, energy and food are the pillars upon which society can further advance. The lack of a secure and economical provision of one of these essentials could result in a breakdown of supply, affordability and accessibility of the two others, especially for the most vulnerable in society. Management of the nexus is of great concern, and the Water Science Forum of the Royal Society of Chemistry have created this brief which outlines some of the challenges and emerging solutions that our members have been focused on.

Introduction

The interdependency between water, energy and food production and consumption is termed the “Water Energy Food Nexus”. Fig. 1 illustrates the global overview of only the main components of the nexus, which alone clearly demonstrate the strength of symbiosis. Waste is also included in the diagram because the volume of waste can have a major bearing on nexus balance. Traditionally, this nexus has been sourced and solved locally, where a region lacking water would have extra water piped in. However, causes that might upset the nexus balance are increasingly requiring global solutions and there is a great need for joined-up activities between stakeholders to mitigate future resource conflicts.

Fig. 1 Global overview of the “Water Energy Food Nexus”.

Discussion

The water challenge

Water is essential for energy production and conversion, and other associated processes such as the refining of energy source products. The water volume requirements for producing different primary energy types vary, and there are significant differences between different types of electricity generation. Freshwater is required for each step of energy extraction and production, refining and processing, transportation and storage. Electric power generation accounts for around 15% of total global freshwater water withdrawals.¹

The energy challenge

Energy is consumed to provide water for domestic, industrial and agricultural applications. Fresh water resource capture, transfer, treatment, and distribution accounts for around 15% of energy use and consumption; and indirect uses can increase this consumption ten-fold.¹ Waste-water collection, transfer, treatment and return to aquatic environs also require significant amounts of energy.

The food challenge

Food production consumes both water and energy in order to grow, harvest, clean and prepare food. This is in addition to using water to create energy, and energy to create and transfer usable water resources. On a global basis, food production is responsible for approximately 6% of total energy use and around 70% of global water use.²

The waste challenge

Waste is a key factor in the balance of the water–energy–food nexus that is often overlooked in discussion. In European countries about 20% of all fresh water resource treated for human consumption is lost through leakage mechanisms; and this figure is much higher in some areas of the world. As well as lost water resource, 20% of all the energy used to collect, treat and distribute the lost water is wasted. A significant quantity of energy is also wasted through inefficiency mechanisms associated with heating and lighting. The most visible, and arguably the most unnecessary, waste is food. It is estimated that 1.3 to 2.0 billion tons – around 33% to 50% of global production – are lost or wasted annually.³ Loss and waste occurs in all steps of the food supply chain. In low-income countries most loss occurs during production, while in developed countries about 100 kilograms (220 lb) per person per year is wasted at the consumption stage. Visible food waste is accompanied by a less noticeable waste of both water and energy consumed during production, preparation, packaging, transport, sale and disposal. Some of this waste is re-used to produce energy via a number of technologies and methods including digestion. However, in terms of the nexus balance this figure is currently small.

Approaching the solution

It is possible to create more sustainable water, energy and food supply and consumption by addressing the mechanisms of waste. Some require technical improvement such as production or process method/efficiency which, in turn, require improvements in science and technology. Other approaches include social factors, for example, simply consuming and/or wasting less. There is potential to provide 60–100% more food by eliminating losses and waste while at the same time freeing up land, energy and water resources.³ The water–energy relationship can be addressed by using less electricity or transportation fuel by making appliances, buildings, and vehicles more efficient; or using them less. Renewable energy technologies such as wind and photovoltaic methods can reduce water use for electricity production and, in an ideal world, even stop it altogether. There is a great drive now for joined-up thinking and cross-discipline collaboration to formulate possible engineering design frameworks for meeting the coming nexus challenge to sustain an estimated 8.3 bn people demanding 50% more energy and food by 2030.⁴

Conclusions

The complex relationships in the water energy food nexus, require informed production and consumption decisions for the near future that can mitigate negative impacts on risk, security, and the environment. Stakeholder engagement can be the key to identify widely accepted nexus solutions.

Other resources

http://www.youtube.com/watch?v=CKW_ux2Xo_w

http://www.radcliffe.harvard.edu/event/2013-peter-p-rogers-water-lecture

http://www.weforum.org/videos/risks-focus-3-water-food-energy-nexus

http://www.exeter.ac.uk/research/events/eventsarchive/water-food-energynexus/

http://www.guardian.co.uk/sustainable-business/video/water-food-energy-nexus-connections

http://www.waternexussolutions.org/21g/the-water-food-energy-nexus.html

http://www.fao.org/energy/81320/en/

Acknowledgements

The authors acknowledge all members of the Water Science Forum of the Royal Society of Chemistry for their helpful discussions.

Notes and references

1. International Energy Agency, Water for Energy, 2011, http://www.worldenergyoutlook.org/resources/water-energynexus/.
2. UNESCO IHE, Institute for Water Education, Water, Food and Energy Security, 2013, http://www.unesco-ihe.org/research-themes/water-food-energy-security.
3. Inst. of Mech. Eng., Global Food: Waste Not, Want Not, 2013, http://www.imeche.org/docs/default-source/reports/Global_Food_Report.pdf?sfvrsn=0.
4. Inst. Of Chem. Eng., The great water-energy-food challenge, TCE, 2014, October 3, E-mail: nexuxchallenge@outlook.com.

Footnote

† This Note was produced by a working party of the Water Science Forum of the Royal Society of Chemistry. The Society is a registered Charity. Its Royal Charter obliges it to serve the public interest by acting in an independent advisory capacity. In order to meet this obligation the members of the Water Science Forum are drawn from a wide range of backgrounds and serve on the committee as individual experts and not as representatives of their employer. The Water Science Forum welcomes comments on this Note. Please send them to the Chairman, Water Science Forum, c/o Royal Society of Chemistry, Burlington House, Piccadilly, London, W1J 0BA, UK.

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