What is the Water-Energy-Food Nexus?

What is the Water-Energy-Food Nexus?

Food, water and energy systems are intimately connected with each other and water is a crucial component to making food and energy systems work. It takes water to grow crops and produce energy and it takes a lot of energy to treat and move water. Food and energy are equally dependent upon each other. The connection between the systems is known as the Water-Energy-Food Nexus. Consider how and where all three are used in the US – as events like droughts, oil spills and fluctuating food prices make clear, the US cannot view these systems in isolation.

Water-Energy-Food Nexus 101

Water footprints take an innovative approach to the Water-Energy-Food Nexus, because they help people understand those connections through the lens of their own water use. Corporations use water footprints to understand how their processes use water and energy and where they can reduce both, thereby saving raw materials and money.

Why is Nexus Thinking So Important?

It takes water – a lot of it – to grow and produce food. Because food is often grown in more arid climates where water can be scarce, water is often taken out of other watersheds and transported long distances for irrigation. This is the case in California – in the country’s most prolific agricultural region, agriculture accounts for 80 percent of all human water use in the state. That water is often returned to water ways contaminated with pathogens from livestock, pesticides, nitrates in groundwater, trace metallic elements and emerging pollutants, including antibiotics and antibiotic-resistant genes excreted by livestock.

Similarly, certain forms of energy production require massive amounts of water. Too much water (which results in flooding) or too little water (which results from drought or overuse) can have a significant impact on electricity production. In addition, water used in power production is returned to the system much hotter than the receiving water body can handle, forming what’s known as thermal pollution. Likewise, it takes a lot of energy to treat and move water for domestic, agricultural and industrial uses, and transporting it can be a significant use of energy when you consider the sometimes vast distances water is moved.

The third leg of this connection is between energy and food. For example, certain commodity crops are grown for energy – corn, soy, sugar are all used to make biodiesel. Likewise, it takes a lot of energy to manufacture inorganic fertilizers and pesticides and to produce fuel for farm equipment.

The heart of the nexus approach is understanding these interdependencies and how they impact food, water and energy security. Creating balance between them requires the work of individuals, businesses and government. Integrated planning, policy and management requires an awareness about how these three systems intersect and why greater coordination is necessary.

Why is the nexus relevant to society and to consumers?

To bring it down to a more personal level, think about a slice of pizza. What do food, water and energy systems have to do with a slice? They all come together in that pizza because it took water and energy to grow the ingredients and to make the energy that transported the ingredients to the pizzeria, then it took energy to bake a pie.

Likewise, the three systems come together in drinking water, household goods and the energy used to power homes and businesses. The Nexus is how and where these three systems intersect. Because actions related to one system can impact one or both of the other systems, it is necessary to take a nexus approach to understand tradeoffs and create balance.

Water-Energy-Food Nexus: By the Numbers

  • Agriculture: Agricultural processes in the US account for 80 percent of fresh water consumption.
  • Food Waste: 25 percent of all freshwater consumed in the US is associated with discarded food; about as much as the volume of Lake Erie.
  • Pumping and Treating Water: In California, for example, water-related energy use accounts for 20 percent of all electricity use in the state. 15 percent of it goes toward moving water large distances for irrigation.
  • Electricity Production: Electricity is water intensive: Nearly half of all water withdrawals – both freshwater and ocean water – in the US are used for cooling at thermoelectric power plants.
  • Ethanol: Corn is the main ethanol feedstock in the US, and in 2017, nearly 40 percent of US corn was converted into ethanol. Using potential food supplies for energy generation can have disastrous results on other parts of the food system, and when drought kills a corn crop, livestock producers who rely on corn as a feed source can find themselves in direct competition with ethanol producers