This year's focus for FAO is on "Exploring the Added-Value of the Water-Energy-Food Nexus". Hosting a seminar at the World Water Week in Stockholm to take a critical look at the “Nexus” to better understand and manage the complex interactions between water, energy and food. 

The agriculture and food sectors depend on water and energy resources, using 70% of water withdrawals globally and 11% of the world’s land. Water is used for agricultural production, forestry and fishery, along the entire agri-food supply chain, and is needed to produce and transport energy in different forms. Energy is required to produce, transport, distribute, prepare and cook food as well as to extract, pump, lift, collect, transport and treat water. The food sector currently accounts for 30% of total end-use energy consumption.

The Need to Boost Resource Use Efficiency in Agriculture 

We need to increase agricultural productivity to ensure sufficient supply of food for a growing population and with limited natural resources. Over the last fifty years, the area of land needed to feed one person has decreased by half as illustrated below. This has been achieved through the intensification of agriculture, which resulted in an increasing use of water for irrigation and energy for fertilizers and machinery. Therefore, today, we need to look at productivity not only from a land, but also a water and energy perspective.

Towards Water-and-Energy-Smart Agriculture

• Modernization of existing irrigation systems to improve services may encourage farmers to reduce groundwater use, as it is often more expensive than surface water supply of similar quality. Improving water use efficiency is also energy-efficient, as it reduces the demand for energy to pump, lift and transport water.
• Pressurized irrigation provides more reliable, flexible and efficient water applications. In general, it requires more energy, but it usually translates into higher yields and economic return.
• Optimizing the water storage capacity of reservoirs and catchments, as well as soil moisture retention, groundwater storage, and deficit irrigation offer opportunities for improved water use efficiencies.
• Energy embedded in the production of inorganic fertilizer is globally significant. Farmers can save indirect energy by optimising the amount of fertilizers they use by reducing fertilizers that are currently being lost and contribute to water pollution and by better integrating organic fertilizers and nitrogen-fixing plants in agriculture production.
• Beyond production, any means of avoiding food losses and waste result in considerable savings in the energy, water and land used to produce this food that no one consumes. They should be systematically encouraged as part of a comprehensive approach to resources use efficiency.

Growing, often competing demands

Not only agriculture, but cities, industry and other users, too, claim increasingly more water, land and energy resources, and at the same time, face problems of environmental degradation and resource scarcity.

The Water-Energy Nexus in Central Asia

In Central Asia, rising energy prices have made it beneficial for upstream countries, like Kyrgyzstan and Tajikistan, to generate hydropower in the winter by releasing water that has formerly been used in spring and summer to irrigate cotton and wheat in downstream countries, such as Uzbekistan, Turkmenistan and Kazakhstan. As a result, downstream countries, maintaining the same crops and production patterns, had insufficient water in summer to satisfy agricultural demand.

Energy for Irrigation: Likely to Increase in the future

Powering the water pumps on a total of 300 million irrigated hectares globally consumes around 62 TWh/ year, in addition to the energy needed for the manufacturing and delivery of irrigation equipment. Most of the energy for irrigation is used for groundwater pumping. As groundwater irrigation, in general, provides greater flexibility than other types in responding to fluctuating water demands, its relative importance is likely to increase.

Synergies and Trade-Offs: Biofuels and Water

Biofuels can potentially be a cleaner alternative to fossil fuels. From the water perspective, the most important characteristic in feedstock production for biofuels is whether it takes place under rainfed or irrigated circumstances. In general, rainfed production of biomass does not substantially alter the water cycle. If bioenergy feedstock is produced on irrigated lands, then the potential impacts on ground water and surface water resources can be a major concern, particularly when it comes to commercial feedstock production.

Biofuels not only use water for feedstock production, but also for processing. Water used in biofuel processing is a strong competitor for local uses, but after use it can be made available for other purposes. These return flows, however, often have negative impacts due to chemical and thermal pollution. The production process of biofuels also uses energy for mechanization, to produce fertilisers and to pump irrigation water.

Overall, biofuel development needs to be considered in the context of land and water availability, energy needs and production, agricultural priorities and, especially in developing countries, rural development for poverty reduction and increased food security.