In the years and decades ahead, water and wastewater utilities can take many different actions to reduce greenhouse gas emissions. But what if they don’t? This is not a pessimistic question, but a very important one. Modelling a future with no mitigation actions – business as usual – is an important part of ensuring that actions happen.

That idea is the basis of WaCCliM’s new approach to understanding business-as-usual futures, the Methodology for Establishing Baseline Scenarios in the Urban Water Sector with ECAM.

The approach builds on the Energy Performance and Carbon Emissions Assessment and Monitoring (ECAM) tool, a first-of-its-kind online tool that allows water and wastewater utilities to take a holistic approach to reducing energy use and greenhouse gas emissions throughout the urban water cycle. ECAM allows utilities to enter their existing data into the tool and model actions they are considering to estimate the benefits of mitigation. The new baseline methodology goes a step further by identifying how emissions would evolve over time if current management and practices were to continue.

As water flows through an urban water cycle to meet the needs of residents and industry, greenhouse gases are produced indirectly through energy consumption, and often released directly from untreated or poorly treated wastewater. Modelling the unchecked growth of these emissions allows utilities to reveal the benefits of investing in mitigation – which they can do by getting more energy efficient, stopping water losses, better managing wastewater and sludge, or extracting and using biogas, among other possibilities.

Baseline scenarios are far from simple models; projecting past developments into the future requires many parameters and the best available data. Scenarios are based on the physical and biochemical characteristics of the emission pathways in the urban water cycle, with key parameters affected by socio-economic, technological and climatic forces, ranging from the numbers of people expected to move to cities to the composition of their diets. For rapidly growing cities in countries with developing economies, the only certainty with these parameters is that they will not stay static in the years ahead.

Yet it is possible to project them. They can be based on the trends derived from international and national databases, journal publications, reports and policy documents – including the reports and models of the Intergovernmental Panel on Climate Change (IPCC), which WaCCliM’s methodology takes as a basis.

There are four steps to the methodology. The first step involves defining the boundaries of the specific urban water cycle to be considered, and the time horizon over which it will be modelled. In the second step, the key parameters and driving factors of the emission trajectory are determined, taking national and global trends into account. The third step is data collection and projection, and for this WaCCliM has developed a custom Excel-based tool, Project ECAM Inputs for GHG Emissions (PEIGE). This generates a projection of business-as-usual conditions in future years that, in the fourth step, can be entered into ECAM’s freely available online interface to compare with alternative scenarios.

The power of this methodology is evident in two initial case studies published by WaCCliM. In Madaba, Jordan, WaCCliM modelled the possible trajectory of the utility Miyahuna’s greenhouse gas emissions under business as usual all the way to 2040. These will be critical years, with population growth, economic development and an influx of refugees widening the gap between water supply and demand in the dry region. The scenarios showed that the direct and indirect greenhouse gases emitted by the utility could increase from around 40,000 tons carbon dioxide equivalent (CO2e) in 2016 to nearly 110,000 in 2040, if the utility were to continue with no changes to its operations.

In San Francisco del Rincón in north-central Mexico, unsustainable abstraction, high water losses and inadequate wastewater treatment challenge the two utilities Sistema de Agua Potable y Alcantarillado de San Francisco (SAPAF) and Sistema Intermunicipal para los Servicios de Tratamiento y Disposición de Aguas Residuales para los Municipios del Rincón (SITRATA). WaCCliM also modelled the trajectory of these utilities’ business-as-usual emissions to 2040. The scenarios showed that emissions from the water supply system might increase by up to 58%, while emissions from the wastewater system could dip by 8% thanks to a gradually expanding treatment area.

Neither in Madaba nor in San Francisco del Rincón, however, did business proceed as usual. Among other measures, the Jordanian utility has upgraded pumps to more efficient models, already achieving 1,000 tons CO2e mitigation per year despite its fast-growing service area. The Mexican utilities, instead of expanding wastewater treatment gradually, have acted much faster to extend the system from 48% of the city to 80%, achieving mitigation of 2,500 tons CO2e per year.

The effects of actions like these need to be measured against something – and the business-as-usual scenarios are that something. The methodology is an important step towards estimating the reduction of utilities’ carbon footprints, and a strong technical component for further implementation of climate policies, right up to regional and national scales.

As global temperatures rise, it is the water cycle that is changing most dramatically, most unpredictably, and with some of the greatest consequences for people everywhere. Climate change is disrupting water availability and quality, amplifying floods and storms, and increasing the frequency of droughts. For water-sector decision makers, all of these impacts add up to a fundamental disruption: decisions that were once based on historical data are now afloat in uncertainties about the climate of the future.

At the same time, the water sector is, itself, a place to take on the drivers of climate change. The sector currently contributes up to 5% of global greenhouse gas emissions, and with demand for water set to increase by 20-30% [1] in the next 30 years, its emissions will only rise – unless something is done.

Municipal systems, global commitments

Strong mitigation potential lies in urban water and wastewater systems, whose energy consumption, mostly driven by fossil fuels, makes up as much as 40% of municipal energy use in some cities. In developing and emerging countries, water and wastewater utilities often rely on inefficient pumps, leaky distribution lines and dated treatment technologies. They emit carbon dioxide from their energy use, and even more potent greenhouse gases – methane and nitrous oxide – from the breakdown of untreated or poorly treated sewage. Since 2014, the project Water and Wastewater Companies for Climate Mitigation (WaCCliM) has been working with selected countries and utilities to prove that in the urban water sector, climate mitigation action can be achieved alongside, and in harmony with, climate-resilient sustainable development.

WaCCliM’s experience has shown that the flow of water into, through and out of cities connects some of the largest commitments of developing and emerging countries. Among these, two stand largest: the Nationally Determined Contributions (NDCs) that governments have pledged in order to reach the climate targets of the Paris Agreement; and the Sustainable Development Goals (SDGs) that they are striving to achieve by 2030.

Clean water and sanitation command their own SDG, Goal 6, but in truth water runs through nearly all of the goals, and unites them with success or failure in climate action. Even in a stable climate, countries would be facing an enormous challenge just to reach Goal 6 – availability and sustainable management of water and sanitation for all. Billions of people still live without safe water, sanitation or both, and the effects undermine other goals like health, equality and the vision of sustainable cities. Now the uncertainties of the climate require thinking even harder about water insecurity, including in cities; about which people have as much water as they need without having more than they can manage, about how clean that water will be under all possible conditions, and about how to generate the energy that will get it there.

A climate-smart roadmap

WaCCliM’s Roadmap to a Low-Carbon Urban Water Utility, a tool for water and wastewater utilities with mitigation goals. © GIZ

The NDCs that countries have submitted reveal an awareness of just how central water is to climate adaptation. According to a Global Water Partnership analysis of 80 NDCs, investing in water infrastructure, institutions or governance is a key priority in 89% of the surveyed countries, and practically all countries indicate that some kind of water action is necessary for adaptation. Far fewer NDCs, however, mention the substantial opportunities to reduce greenhouse gas emissions found in the urban water and wastewater sector. It’s here that WaCCliM is guiding countries to mitigation opportunities, starting at the utility level.

The Project has introduced a roadmap of systematic steps and measures towards low-carbon water and wastewater utilities that can also plan for climate risks and improve their services to better support sustainable development. Helping utilities on this path is the project’s Energy Performance and Carbon Emissions Assessment and Monitoring Tool (ECAM), which any utility can use to assess its emissions and pinpoint opportunities to use less energy – or even generate its own energy.

From the utility up

WaCCliM has piloted mitigation solutions, ranging from energy-efficient pumps to technologies for generating power with wastewater biodigesters, with utilities in Jordan, Mexico, Peru and Thailand. The measures prioritised in these pilots have achieved total mitigation equivalent to 10,000 tons of carbon dioxide – or planting 50,000 trees – per year. WaCCliM is also introducing adaptation thinking by helping the pilot utilities develop climate risk plans, advising utility personnel on ways to build water system resilience to the risks identified, reducing water losses and recycling treated wastewater. The toolbox of both mitigation and adaptation planning measures will be available to utilities everywhere on the knowledge platform Climate Smart Water.

Water metering in Moroleón, Mexico. © GIZ/Maurice Ressel

Through these tools WaCCliM´s approach can substantially help meet NDCs across developing and emerging countries, and by building climate-smart urban water systems, it can help achieve the SDGs, too. This is a big vision, and it has to be achieved on a local, national and global scale. So while WaCCliM works with national and international partners to enable local action, it does this with a larger transformation in mind. The water and wastewater utilities using WaCCliM tools to pioneer greenhouse gas benchmarking and climate-smart planning are becoming national sector leaders, and they are providing evidence for an increased consideration of water as a sector for combined mitigation and adaptation action in the next round of NDCs. As that happens, they will also be poised to make a significant contribution to the sustainable development agenda.


[1] UN Water (2019): World Water Development Report 2019

The transition to low-carbon urban water utilities is an innovative idea, currently embraced only by a few forward-thinking utilities. Early adopters of the WaCCliM Roadmap to a Low-Carbon Urban Water Utility are well positioned for an uncertain water-climate future. This roadmap is directed at urban water utility managers in charge of planning future actions, as well as at the stakeholders who will support the utility’s action plans.

“The Roadmap to a Low-Carbon Urban Water Utility, a legacy from the WaCCliM project, builds on the experiences gained during the implementation of the project. It will support water utility managers around the world in their efforts to improve performance and achieve carbon neutrality of their utilities while raising the awareness of policy-makers to the substantial contributions the water sector can provide in meeting greenhouse-gas reduction targets. Local action is needed to support global targets!”

Thomas Stratenwerth, Head of Division – General, European and International Water Management Issues
Federal Ministry for the Environment, Nature Conservation and Nuclear Safety, Germany


The Roadmap to a Low-Carbon Urban Water Utility presents water professionals with an approach to address their most pressing challenges, while reducing carbon emissions through measures that either have a return on investment through energy or water savings, or that correspond to planned investments as part of the asset management plan to maintain or improve their services. Utilities adopting this approach are contributing to a carbon-neutral future, by instigating a change of mind-set, not only in urban water management but also by inspiring all other urban services through sharing the risks and the urgency to act to avoid aggravated impacts of climate change, from which water utilities are among the first victims: water scarcity, flooding and deteriorated water quality.

Why a roadmap and for whom?

The transition to low-carbon urban water utilities is an innovative idea, currently embraced only by a few forward-thinking utilities. This roadmap is directed at urban water utility managers in charge of planning future actions, as well as at the stakeholders who will support the utility’s action plans. Since only a few ‘early adopter’ utilities have embarked on a low-carbon transition, this roadmap intends to support other utilities in understanding and championing the need for contributing to a carbon-neutral future, and to guide them through a process of change. This roadmap can be applied to all utilities worldwide, but was specifically developed with utilities in emerging economies in mind, because the service performance and data management challenges are often prominent in their operations and future planning.

Setting a path for utilities to transition to low-carbon

The Water and Wastewater Companies for Climate Mitigation (WaCCliM) project supports potable water and wastewater utilities –also referred to as urban water utilities – with the implementation of measures that enhance their service performance and lower their carbon emissions. The project is a global initiative, with the overarching goal to transition to a carbon-neutral urban water sector. The approach laid out in this document was specifically developed with water utilities in emerging economies in mind within the context of the WaCCliM project, but it can serve utilities anywhere as climate change is a global problem. It targets reducing the water, energy and carbon footprints of urban water utilities through an iterative five-step process which may be used by utilities to find their own path to a low-carbon future. The roadmap is intended to guide urban water utility managers through these steps and leads to resources hosted on the Knowledge Platform ‘Climate Smart Water’, which follows the same structure as this roadmap.

The Roadmap to a Low-Carbon Urban Water Utility is available in English, Spanish and Thai.