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.