Think of a simple slice of pizza.
At first glance, it seems pretty basic – dough, tomato sauce and cheese – but look closer and you’ll find that those three ingredients have a rich story to tell.
As you deconstruct your slice of pizza, consider the water and energy required to make it. You need to add water to the flour and yeast to make the dough, but what about the water used to grow the wheat that’s milled into flour that makes up the dough that gets baked into your pizza? Or what about the water needed to produce the gooey mozzarella? You don’t see this “hidden water” in your slice of pizza, but it’s there.
Through a series of studies, the Water Footprint Network (WFN) broke down the water footprint of a margherita pizza (one topped with tomato, mozzarella and basil). A water footprint looks at the direct and virtual water used to produce an item. The WFN found that to make a single pizza, it requires 333 gallons (1,260 litres) of water, enough to fill almost ten bathtubs!
Producing one calorie of food requires about one litre of water. That means you “eat” more water than you drink. Now think of the energy going into your pizza. There’s the direct energy that goes into warming the pie, but there’s also the virtual energy that goes into farming the crops (think tractors and fossil fuels required to produce fertilisers and pesticides), processing and distributing the ingredients and even the energy that was required to manufacture the pizza oven.
You may not have realised it, but just for a US$ 10 plain cheese pie, you rely on a global distribution network, industrial agriculture, fossil fuels and a LOT of water. In fact, water, energy and food are interrelated: you need water and energy to produce food; you need energy to treat and move water, and you need water to cool power plants and to produce natural gas and oil. The more you probe these networks, the more complex they become.
The next time you grab a slice of pizza you’ll know more about all that’s required for each tasty bite, but what about all the other things you consume? Do they also add up to a lot of food, water and energy? And how does your consumption of food, water and energy directly or indirectly impact our natural resources and ecosystems?
Let’s take a broader look as we further explore the nexus.
Food, Water and Energy Systems
You’ve had a taste of how these systems – food, water and energy – are connected, but how does the “nexus” of these systems work on a larger scale, such as in your community or at the national level? It’s also important to understand how these systems and their interactions impact our environment.
The Systems
Food System
A food system encompasses the activities, resources and people involved in bringing food from the farm to the table, including but not limited to the following: Growing and harvesting crops; Breeding, housing, feeding and slaughtering animals for food;
Catching and harvesting aquatic plants and animals for food; Processing raw plant and animal materials into retail products; Transporting feed, animals, produce and other goods; Storing and selling products at retail outlets; Preparing and eating food; and the land, labour, soil, energy, animals, seeds and other resources involved in making the aforementioned activities possible.
Water System
A water system supplies water for human consumption and treats wastewater to protect public and ecological health. But the fundamental way to view a water system is as a watershed, or an area of land in which all the water under it or that drains off of it goes into the same place.
A watershed can be any shape and size and can cross political boundaries. According to the EPA, there are 2,110 watersheds in the continental United States. Unfortunately, water doesn’t always exist when and where people need it. In order to meet the needs of individuals and communities, water is moved within and between watersheds. In essence, we alter water systems so we can fulfill our agricultural, municipal, commercial, industrial and energy production needs.
Energy System
An energy system includes the steps required to generate, transmit and distribute electricity, as well as the steps required to produce and distribute transportation fuels. Electricity is typically generated at a power plant running on fossil fuel combustion – such as burning coal or natural gas – or nuclear fission. It is also generated by harnessing energy from flowing water, wind, sunlight and the earth’s heat.
Transportation fuels are also part of an energy system, which includes the production, refinement and distribution of oil and natural gas, as well as the production and processing of feed stocks (such as corn used to produce ethanol) for biofuels.
Interactions Between Systems
Food and Water
The water required for food production and processing is immense. Irrigating crops accounts for about 30 per cent of all of the water withdrawals in the United States. Water withdrawal is when “water is diverted or withdrawn from a surface water or groundwater source” and then returned. Consumptive water use, on the other hand, is “water use that permanently withdraws water from its source; water that is no longer available because it has evaporated, been transpired by plants, incorporated into products or crops, consumed by people or livestock, or otherwise removed from the immediate water environment.
Irrigation competes with other water uses such as power plant cooling, municipal drinking water and fossil fuel production. When parts of the country face drought, water sources can become strained, creating problems for farmers who rely on irrigation for their crops. This is especially troublesome for irrigators when restrictions are placed on water use by local and regional authorities. In addition, food production can significantly impact the quality of water bodies through agricultural runoff polluted with fertilisers, pesticides and manure from farms, fields and feedlots.
Water and Energy
Large amounts of water are required for conventional power production, primarily for cooling. In fact, nearly half of all water withdrawals – both freshwater and ocean water – in the United States are used for thermoelectric power plant cooling. Hundreds of large-scale power plants across the country are highly dependent on water resources, withdrawing 58 billion gallons of water from the ocean and 143 billion gallons of freshwater each day – more than any other water use category, including irrigation and public water supplies.
For this reason, most power plants are located near rivers, lakes or the sea. Power plants can be impacted by drought when surface water levels drop, leaving them without access to cooling water and forcing the plants to reduce their operations, sometimes even shutting them down altogether. During drier, warmer periods, the temperature of the water bodies that power plants draw from can rise too high to effectively cool the plants, or the water that runs through the plants can be warmed to such an excessive degree that it can harm the water body’s ecology.
Food and Energy
Agriculture and energy have always been connected, but modern technology and industrialisation have significantly increased energy requirements for agricultural and food production. Energy inputs to agriculture include:
» Fertiliser Production
Industrial farms use synthetic fertilisers, which require fossil fuel inputs (primarily natural gas) to be produced. Other fertilising agents (e.g., potassium and phosphorus) use energy as they are mined and transported.
» Water Consumption
Most forms of agriculture are water-intensive. As stated earlier, pumping and moving large volumes of irrigation water requires energy.
» Farm Equipment
Modern agriculture relies upon machinery that runs on gasoline and diesel fuel (e.g., tractors and combines), and equipment that uses electricity (e.g., lights, pumps, fans, etc.).
» Processing, Packaging & Transportation
Most of the food produced today is processed and packaged, increasing its energy and water footprints.
» Transportation
Because the food industry has been consolidated – fewer companies now control production – food is often transported long distances from a select few locations, requiring additional energy to power planes, trains, cars and trucks.
» Industrial Livestock Farms & Energy
Most meat, eggs and dairy products are now derived from livestock raised in industrial “concentrated animal feeding operations,” or “CAFOs”. Commonly referred to by critics as “factory farms,” these facilities raise thousands of animals in confined conditions without access to pasture. Such farms require tremendous quantities of feed produced by industrial crop farms using the energy-intensive processes described above.
Source: watercalculator.org, Grace Communications Foundation
