Managing the water-energy nexus

The challenge
Water and energy are fundamental pillars for economic and social development worldwide and they are inextricably linked: Water is needed for different stages of energy production and energy is required to extract, supply, distribute and treat water and wastewater. As global demand for both energy and water is set to increase significantly over the coming years, this interdependency will have significant implications for both energy and water security.

The future
According to the International Energy Agency (IEA), the water sector’s energy consumption is projected to more than double by 2040. However, a rise in water demand does not necessarily have to mean an equal rise in energy consumption. If the existing potentials of energy efficiency and energy recovery in the water sector are utilised, the sector’s energy consumption can actually be reduced by 15 percent in 2040.

Explore associated sectors

Today, wastewater collection and treatment account for a quarter of the water sector’s total electricity consumption. According to IEA, this demand is expected to rise by more than 60 percent by 2040 as more wastewater is being collected and treated. However, the organic content in the wastewater can also be used to produce energy and thereby contribute to covering the sector’s energy needs.

In order to reduce its dependency on traditional sources of energy, water utilities need to be highly energy efficient throughout the water cycle, utilise synergies with sustainable energy sources like solar and wind and recover energy from wastewater treatment plants. In Denmark, water utilities are required to benchmark their performance, which makes it possible to establish specific targets for energy consumption, energy efficiency and energy recovery.

In Denmark – as in many other countries – wastewater treatment plants are moving from being heavy consumers of energy to becoming energy and resource recovery facilities. By utilising the biogas potential – along with energy saving technology – several plants are now producing more energy than they consume. This has led the most ambitious Danish water utilities to set goals of achieving a carbon-neutral water sector across the entire water cycle.

Connect with us: Cecilie Buch Thomsen, Senior Project Manager,