Hayati Yarkadas Opinion - 16/June/2022

The water-energy nexus: an untapped resource for major energy savings

Water requires energy. When we move it, clean it, heat it and cool it—energy moves with it. These two precious resources come together seamlessly in our daily lives, but they can also jointly create significant energy savings. Unleashing the potential of the water-energy nexus will drive substantial energy savings to repower the EU while drastically reducing greenhouse gas emissions, says Hayati Yarkadas at Xylem Europe

The views expressed are those of the author and do not necessarily reflect the position of FORESIGHT Climate & Energy


We must move to an energy-neutral wastewater sector to achieve climate neutrality in Europe

The water-energy nexus refers to the link between energy use in water management and water use in energy production. Water and wastewater infrastructure account for 3.7% of the global electricity consumption. The good news is that any efficiency gains in one benefits the other.

And by using high-efficiency technologies, we can cut half of that energy consumption at zero or negative cost. This would be equivalent to removing 9.2 million fossil-fuelled cars per year and it would free up $40 billion to invest in other types of water infrastructure.

The nexus also holds the potential to generate large-scale energy and water savings across sectors and drastically reduce greenhouse gas (GHG) emissions—an important element to address the impending climate change crisis.




The European Commission is revising the EU Urban Wastewater Directive which has been in place since 1991. This presents a major opportunity for lawmakers to update legislation with the latest trends in the wastewater sector and reduce the energy used to treat water.

Wastewater utilities are at the centre of this important work with many already adopting energy-saving measures.

A good way forward is to introduce energy efficiency targets for wastewater treatment plants of a certain size—for instance, of over 10,000 population equivalent (pe)—and consider mandatory energy audits that include measuring water efficiency.

Establishing GHG emission reduction targets for wastewater utilities is also key to addressing the energy-climate challenge. GHG emission targets for larger treatment plants of over 100,000 pe should be in place by 2035 and for the wider sector by 2040.



Lastly, addressing the issue of water leakages is critical to conserving energy. Due to water leakages, more than 20% of clean drinking water is lost in distribution networks of about half of the EU Member States—in some countries this percentage is as high as 60%. This means we use energy to clean and move this water but then is lost as it leaks through an old pipe or busted water main.

When this happens, we lose twice—the water itself and the energy required to treat, pump and deliver it. The city of Brussels, Belgium, experiences 23% of water losses – wasting 1.77 gigawatts, or 634.4 metric tons of CO2-equivalent, per year. This is equivalent to 138 cars running non-stop on natural gas for a whole year that can easily be solved through existing solutions.



Digital solutions can achieve significant energy savings within a short period of time with limited investment needs. Utilities across the globe are proof positive that these solutions work.

A wastewater treatment plant with 400,000 residents in Cuxhaven, Germany, achieved a 26% reduction in aeration energy usage. This corresponds to 1.1 million kilowatt-hours annually, or 485 metric tons of CO2-equivalent, in savings, by simply using digital solutions.

Across Europe, the implementation of similar real-time support solutions to wastewater treatment can further reduce energy use and GHG emissions by 0.3 million metric tons of CO2-equivalent. This, in combination with intelligent pumps for wastewater management, can bring huge energy savings thus considerably lowering costs for utilities.

Water technologies for energy savings and promoting green energy production are tried, tested and readily available. We can make a profound difference by coming together with wastewater utilities to seize this moment to promote the dialogue around water and bring impactful policy approaches and technologies to solve water and energy challenges. •


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