Water-Energy Nexus

World Energy Outlook Special Report

This excerpt from the World Energy Outlook 2016 looks at the critical interplay between water and energy, with an emphasis on the stress points that arise as the linkages between these two sectors intensify. The analysis assesses the current and future freshwater requirements for energy production, highlighting potential vulnerabilities and key stress points. In addition, for the first time, the World Energy Outlook looks at the energy-for-water relationship, providing a first systematic global estimate of the energy requirements for different processes in the water sector, including water supply, wastewater treatment and desalination.

The interdependency of water and energy is set to intensify in the coming years, with significant implications for both energy and water security. Each resource faces rising demands and constraints in many regions as a consequence of economic and population growth and climate change.

The report finds that over the next 25 years, the amount of energy used in the water sector will more than double, mostly because of desalination projects. By 2040, these desalination projects will account for 20% of water-related electricity demand. Large-scale water transfer projects and increasing demand for wastewater treatment (and higher levels of treatment) also contribute to the water sector’s rising energy needs.

The water sector’s share of global electricity consumption remains around 4% by 2040, according to WEO-2016, but the figure hides some large regional differences. In the United States and the European Union, the water sector’s share of total electricity consumption is around 3%. In the Middle East, on the other hand, the share increases from 9% in 2015 to 16% by 2040, due to a rise in desalination capacity.

The energy sector is also set to become thirstier over the next decades, with energy-related water consumption increasing by nearly 60% between 2014 and 2040. Some technologies, such as wind and solar PV, require very little water, but others like biofuels production, concentrating solar power, carbon capture and storage (CCS) and nuclear power can have more significant water demands. As such, switching to a lower carbon pathway could exacerbate water stress or be limited by it if it is not properly managed, according to WEO-2016.

The availability of water, particularly for emerging economies, could become an increasingly important issue. For instance, demand for water from many end users is increasing in China and India, which both rely on nuclear and coal-fired power plants, many of which are located in areas of water stress.

Policies and technologies already exist that can help reduce water and energy demand, and ease potential chokepoints in the water-energy nexus. These include integrating energy and water policymaking, co-locating energy and water infrastructure, utilising the energy embedded in wastewater, using alternative sources of water for energy and improving the efficiency of both sectors.