The food-energy-water (FEW) nexus, a concept that describes the interdependence of the world’s complex resource systems, has been drawing much interest and activity in the sustainability community recently. The food-energy-water nexus approach (or simply the nexus approach) provides a framework for tackling the grand challenges of ensuring food, energy, and water security for humanity in a sustainable way. In other words, it aims to ensure economic, reliable access to food, energy, water, and other resources such as land, while preserving biodiversity, ecosystems, and other natural systems. Considering these challenges from a nexus perspective means taking a systems approach rather than addres using isolated sectors’ challenges individually.
Several major global drivers make it important to look at the grand challenges in terms of systems. Globalization of markets enables the spread of technology and innovation for more-efficient resource use, but also higher consumption. Population growth and a growing middle class together increase demand for resources and change consumption patterns. Urbanization creates concentrated demand for resources, often at large distances from where the resources are produced. Climate change and the associated weather patterns can challenge local livelihoods or make some regions unfit for life or agriculture altogether. Some of these drivers on their own have apparent benefits, but taken together they can jeopardize the security of food, energy, and water for local or regional populations.
Various approaches exist to address challenges arising from strain on limited resources and system upsets due to these global drivers. Methods that target the challenges of an individual sector carry the risk of an inherent bias toward that sector and can put heavy strain on other resources. Even a binary approach, such as one that considers the nexus between energy and water, carries the same risk.
The FEW nexus approach seeks the optimal management of tradeoffs and maximization of benefits across a system, focusing on system outcomes rather than the productivity of individual sectors. This approach challenges people to think about problems in terms of larger integrated systems beyond their traditional boundaries, recognizing potential tradeoffs, synergies, and opportunities.
There are many examples of systems where operations in one sector rely heavily and put strain on others. Production of biofuels is water-intensive and can compete with food production for resources like land and soil; raising livestock requires water and often extensive transportation; importing water or desalination of water for farming in regions of water scarcity has significant energy and environmental impacts. The nexus approach recognizes the dynamic nature of complex systems and the interactions within them to optimize solutions across sectors and scales, as well as time.
For instance, hydraulic fracturing (fracking) requires substantial amounts of water for the extraction of natural gas and oil. Some drillers are beginning to recover fracking water for reuse in applications such as irrigation to alleviate water stress. In energy-positive wastewater treatment technology, food waste in wastewater is anaerobically digested to produce methane, making wastewater treatment a potentially energy-yielding process, whereas current standard processes tend to be energy-intensive.
The various resources needed to meet the growing demand for food, energy, and water are finite and at times and in some places are very limited. It is therefore important to be aware of the unique needs and limitations of each situation. While models serve as useful tools, there are no one-size-fits-all solutions. This is because regional needs and resource availability of otherwise similar systems can vary greatly. For example, one system that has demand for a certain amount of energy can have plenty of water but very limited land, while another system with a similar demand for energy might have plenty of land but suffer from water scarcity. Under the nexus approach, these two scenarios would require different priorities for meeting human demand while appropriately balancing the finite resources.
The challenge at the FEW nexus may sound like a social or political issue, and indeed it is. Yet it is also a technical one, since solutions require technological development and innovation. There is a need for comprehensive tools and methodologies for designing complex integrated systems that must accommodate changes over time and balance resource use to meet humanity’s demands. Chemical engineers in particular have an opportunity to contribute, as systems are at the core of our profession, and systems thinking is key to the nexus approach. Chemical engineers will need to work closely with interdisciplinary collaborators and stakeholders to inform technical, business, and policy decisions.
The FEW nexus approach is applicable to countless complex systems that chemical engineers in various fields design, optimize, and work with. All of these systems involve complex interactions between drivers, sectors, and resources. Each system is unique in its needs and opportunities, and in some way each affects the global food-energy-water nexus.
I encourage you to consider expanding the boundaries around your particular systems to appreciate the interrelations across sectors and to think about the impact your decisions in one sector will have on the others.
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