Energy-Water-Carbon Nexus


Energy depends on water, it is essential for all phases of energy production, from fossil fuels to biofuels and power generation. To feed the growing population and meet the increasing needs of economy, the expansion of the energy sector cannot be avoided, which puts more pressures on fresh water resources and water suppliers. Meanwhile, changes in our climate directly impact the availability and quality of water, creating unprecedented challenges for water and wastewater utilities around the globe.


Water depends on energy. Water and wastewater utilities typically contribute 30-40% to a municipality’s energy use. In the coming decades, less abundant water will demand even more energy to abstract, treat and distribute. At the same time, the water sector is exposed to the risks and uncertainties associated with future energy fluctuations and prices. These challenges provide a window of opportunity to initiate a paradigm shift towards climate-smart and sustainable urban water services, by adopting energy efficiency measures or generating renewable energy from biogas.


Carbon emissions have a positive correlation with energy consumption. Despite being affected by climate change, the urban water sector also contributes to the global greenhouse gas emissions. The widespread use of outdated or inappropriate treatment technologies and pumps leads to unnecessarily high carbon emissions from energy use, and of methane and nitrous oxide from wastewater treatment processes. A sustained expansion of wastewater treatment, combined with appropriate technologies or concepts, is critical to put us on a climate-smart path.

Our Approach

The WaCCliM project works across local, national and international levels,
and engages with national stakeholders around water utilities in
Jordan, Mexico and Peru.


At the local level, WaCCliM provides user-focused technical support, approaches and tools that enable committed water and wastewater utilities to assess, monitor and reduce their greenhouse gas emissions while enhancing their ability to adapt to climate change. The resulting operational improvements also aim to generate spin-off benefits and cost savings in energy, labour, chemicals, maintenance and disposal. To achieve this, pilot companies are supported by project experts who develop baseline studies, options studies and trainings to strengthen capacities on low-carbon and resilient solutions.


At the national level, the project works with its political counterparts and national associations in partner countries to improve the framework conditions for the financing and implementation of climate-smart measures in the urban water sector.


At the international level, WaCCliM develops and scales up knowledge on water and climate change through conferences, expert groups, technical guidelines and online resources. Effective implementation will help advocate for improved financing mechanisms and political incentives to replicate the success of demonstration projects in the partner countries and elsewhere.

The WaCCliM Roadmap

WaCCliM employs a circular perspective on water management and considers mitigation and adaptation potential in all components of the urban water cycle, from water supply to wastewater and reuse. The project offers utilities a Roadmap to a Low-Carbon Urban Water Utility.

The Energy Performance and Carbon Emissions Assessment and Monitoring (ECAM) Tool, a carbon footprint tool for water and wastewater utilities, is a cornerstone of this approach. ECAM helps utilities understand their overall energy usage and total greenhouse gas emissions at a system-wide level and indicates areas to reduce emissions, considering all components of the urban water cycle, from water supply to wastewater treatment, sludge management and water reuse. The mitigation-focused ECAM Tool integrates well with WaCCliM’s activities in support of adaptation, which improve the capacity of utilities to develop climate risk plans, analyse the co-benefits of mitigation and adaptation measures, and prioritise measures for more climate risk-resilient water and wastewater systems.


By helping utilities reduce overall costs through reducing energy consumption and greenhouse emissions,
they become more resilient to climate change impacts, including water availability and water quality.
Integrating water and climate agendas presents opportunities to unlock climate financing
for utilities working hand-in-hand with their cities.

Energy Efficiency

Because utilities spend 10–35% of their operational costs on energy, investments in energy efficiency and production in urban water systems can be extremely cost effective. If well planned, these investments have pay-back times of only a few years. While reducing costs, such climate-smart investments reduce a utility’s carbon footprint, and complement adaptation planning to make urban areas more resilient to the risks brought by climate change.

Water Efficiency

Reducing water losses, reusing water, using rain water or conserving water can all help significantly reduce greenhouse gas emissions and energy consumption in existing urban water systems; make urban water systems more resilient to climate change related risks, includig flooding and droughts; and defer the need for new drinking water and wastewater infrastructure.

Adequate Sludge Management

Costs associated with sludge management can constitute up to half of the total expenses of wastewater facilities. As the world’s population grows and legal requirements become stricter, these costs may increase overtime. Effective sludge management tackles these challenges by shifting the perspective from waste production to resource recovery of water energy, nutrients and other valuable materials.

Decrease Untreated Sewage

Globally, approximately 80% of wastewater is discharged to the environment untreated, and as much as 95 percent in some low-income countries. In some middle-income countries reducing untreated sewage discharge would reduce one of the biggest sources of greenhouse gas emissions, while providing public health and wider ecosystem benefits. A massive expansion of wastewater treatment, coupled with sustainable treatment technologies, would put us on the path towards carbon neutrality.