How will water utilities cut emissions in half and help decarbonise the water sector?

Water operators have long been stewards of an essential resource, and water infrastructure is a cornerstone of every prosperous economy. But today’s water systems are also major sources of greenhouse gases (GHGs). And this figure is set to spiral as utilities work towards the UN’s Sustainable Development Goal of universal access to water and sanitation by 2030.

How can water utilities quickly become part of the solution to climate change while continuing to serve their communities?

After different assessments, we see that utilities could drastically reduce electricity and process-related GHG emissions across water and wastewater infrastructure quickly and cost-effectively using existing high-efficiency technologies.

An increasing number of utility operators are committing to “net zero” emissions targets, along with detailed roadmaps for achieving them. Efficient technologies, along with changes in processes, policies and practices, can drive rapid progress without adding costs to current operations.

By embracing these opportunities today, utilities can free up capital to fund water and wastewater infrastructure upgrades while reducing their GHG emissions. As a sector built on serving communities and protecting the environment, it is time for water to take its place in climate discussions and lead the way with action.

The water sector could become one of the fastest to decarbonise, and a powerful example for others.

Descarbonising the water sector: at neutral to negative cost

An interesting initial Xylem study on wastewater infrastructure, entitled “Powering the Wastewater Renaissance”, evaluated 18 distinct electricity-related emissions abatement opportunities in three regions: United States, Europe, and China. Core findings from this study, and from a follow-up analysis of the clean water sector, are summarized as follows:

  • 50% of energy-related emissions from the wastewater sector can be abated with existing technologies, such as intelligent wastewater pumping systems, adaptive mixers with variable speed drives, and real-time decision support systems.
  • ~95% of the impact is achievable at zero or negative cost.
  • Reducing energy-related emissions in the wastewater sector is directly related to the pace of adoption of existing technologies. It does not require new technologies or carbon pricing policies.
  • Existing technologies can also reduce process emissions. For example, intelligent mixing and aeration systems allow for monitoring and modelling that can reduce process-related GHG emissions by limiting nitrous oxide production.
  • In clean water, readily deployable high-efficiency technologies also have a material impact on emissions reduction. Technologies such as ultraviolet (UV) disinfection and advanced metering infrastructures (AMI) deliver significant emissions abatement throughout the water production plant and water distribution network.

Infrastructure decisions made today will have consequences for decades to come

While investment and research are still required to advance the sector’s ability to eliminate emissions, particularly with regard to process emissions, the technology and solutions exist today to make meaningful impact. In the UK alone, it is estimated that utilities could save up to one million tonnes of greenhouse gases by reaching net zero in 2030.

Leading utilities are making swift progress towards net zero

Water utilities around the world are already setting firm net-zero targets and beginning to deliver on them. For example, UK water utilities have almost halved operational emissions since 2011 through a combination of energy efficiency measures, renewable energy and the production of biomethane from sewage treatment processes. In the United States, the City of Gresham’s wastewater treatment plant is the first in the Pacific Northwest to generate more electricity than it consumes each year by using biogas generation and recovery, saving the city about $500,000 per year.

These experiences demonstrate that by prioritising emissions reductions, water operators can achieve big results quickly, affordably and at minimal risk.

As of October 2011, Global Water Intelligence identified 65 water and wastewater companies with net-zero, carbon and climate neutrality targets. They include some of the world’s largest utilities, serving more than one million people.

From Melbourne Water to the Metropolitan Water District of Southern California and Thames Water in the UK, utilities across all geographies are increasing their accountability on the path to net zero.

Published in: Nº87 FuturENVIRO – February – March 2022