From water to plate and from plug to field

by Adrián Mateo | Aug 29, 2025 | CARTIF Blog, Energy

Three problems, one only answer: water-energy-food nexus

This year we´ve experienced situations as diverse as a widespread blackout that left us without power and basic services for several hours; a period of intense rain that, while providing sufficient water, also caused flooding in certain regions, and heat waves that have led to fires and droughts affecting forests and farmland.

If all these events are causing a huge headache for us, who live in a socially and technologically developed country with the capacity for prevention and response, it is logical to assume that in other contexts with far fewer possibilities, their impacts will be exponentially more damaging.

A clear example of this is the African continent, which, despite having a vast array of natural resources, constantly faces energy, food, and resource management challenges. To make matters worse, its current and future economic and demographic development only exacerbates these problems, as greater social growth implies greater demands for electricity, water, and food.

Everything is connected (even it seems it doesn´t)

When we experience a drought, our minds often focus on the lack of water for drinking or irrigating crops. However, a drought can also mean less hydroelectric production and, therefore, more pressure on the grid and electricity prices. If harvests are reduced due to lack of water or extreme heat, food production plummets and, consequently, food prices skyrocket. If a power outage prevents water from being pumped or food from being stored, the problem worsens.

This web of interdependencies is no coincidence. Water, energy, and food form an interconnected system where any change in one element can trigger effects on the others. That’s why the approach known as the Water-Energy-Food Nexus Methodology (or WEF Nexus Methodology) has been promoted for years.

What is the NEXO approach?

NEXO proposes, like many other theories, that the best way to address challenges related to natural resources is to move away from traditional silo thinking (understanding each resource as an individual entity, separate from the rest) and instead approach them in an integrated manner, understanding them as complex and interconnected systems in which acting on one will affect another, either negatively or positively. This systemic methodological approach analyzes how water, energy, and food interact with each other, while also including the influence of other associated factors such as the economy, demographics, climate change, and so on.

Rather than thinking “how do we improve agriculture?” or “how do we guarantee the electricity supply?”, the NEXO approach leads us to ask how we can guarantee sustainable access to all three resources simultaneously, without harming any and maximizing joint benefits. This approach allows us to anticipate conflicts, optimize resources, and make more balanced decisions in highly complex contexts.

Model to understand (and to decide better)

But of course, understanding and predicting these relationships is not easy. How do you measure the impact of a new dam on agricultural production? What effect does an increase in fuel prices have on water use in a region? How does urban growth influence food security?

To answer these questions, we need to study how these relationships have worked in the past. This is achieved through real historical data that feeds models: tools that digitally represent the relationships between the different elements of the system. These models draw on historical values ​​to simulate different future scenarios, allowing us to analyze the effects of different political or strategic decisions. They do not seek to offer a single answer, but rather to create a framework for evaluating alternatives and making informed decisions.

Africa has a real laboratory: ONEPlanET case

The ONEPlanET Project, of which CARTIF is a key partner and a key element, was born from this approach. As part of the Horizon Europe research program, ONEPlanET began in November 2022 and will hold its final event next October in Cape Verde. Its main objective is to contribute to sustainable development in Africa by creating a common WEF Nexus modeling framework, which allows for the simulation and evaluation of different policy and resource management alternatives. To this end, three river basins have been chosen as case studies: the Inkomati-Usuthu Basin (South Africa), the Bani River Basin (Mali-Ivory Coast), and the Songwe River Basin (Tanzania-Malawi).

The initial stages consisted of an in-depth study of the case studies, organizing in-person workshops with local stakeholders (NGOs, policymakers, universities, etc.). The more technical sections then began, involving the characterization of the specific models for each pilot, the collection of data to feed them, and the development of the models themselves and their visualization tools. Currently, work is focused on the presentation and accessibility of the results. To this end, two avenues have been designed: an online tool aimed at technical users and a board game to raise awareness among broader audiences about the challenges of the nexus.

CARTIF has participated in every stage of the project: from workshops with local organizations and data collection to the creation of the models and the development of the two results visualization options.

A tool to understand the present and design the future

Although ONEPlanET is being developed in Africa, the NEXO approach and the modeling tools it promotes are replicable anywhere in the world and at any scale, provided the required data are available. In an increasingly interdependent global context, marked by climate change, resource pressure, and growing uncertainty, understanding how water, energy, and food interact is more urgent than ever.

Because the challenges of the future and the present don’t come in watertight compartments. And neither should the solutions.

Climate and sustainability policies, how are they related and why are they essential for the future of the planet?

by Adrián Mateo | Apr 14, 2023 | CARTIF Blog, Energy

Climate change is a phenomenon which has been scientifically observed for several decades, but it was not until the 1980´s that the term became widely popular and it has been growing ever since. Nowadays, not a week goes by without a new alarming headline appears, warning of record temperatures, decreasing rainfall, and the more frequent and damaging natural disasters.

Against this backdrop, mass media and public awareness of climate change has increased and, consequently, the pressure on governments and companies to establish more effective policies. Thus, climate and sustainability policies are created as actions and measures adopted by companies and policy-makers to face the climate change challenges and foster a sustainable future.

Although it was in 1972 when the United Nations Environment Programme (UNEP) was created at the 1st United Nations Conference on the Environment, concern for environmental security is not a recent topic, but it is estimated that as early as 1750 b.C the Mesopotamian Hammurabi Code established penalties for those who damage the nature.

From then until today, climatic science has changed a lot and, currently, the Conference of the Parties (COP) are held annually. They are summits held by the United Nations Framework Convention on Climate Change (UNFCCC) in which the 197 member parties reach a consensus on climate measures for the coming years. Out of the 27 COPs that have been held, the most relevant have undoubtedly been COP3 or the Kyoto Protocol and COP21 or the Paris Agreement.

Climate policies are mainly focused on cutting Greenhouse Gas (GHG) emissions, which are the major drivers of global warming. To achieve this goal, governments promote renewable energy sources, improved energy efficiency as well as independence from fossil fuel in the main economic sectors (e.g. transport, buildings and industry).

Climate policies ofthen have a specific objective when they are implemented, but they might sometimes generate unexpected effects, both positive (co-benefits) and negative (trade-offs). These co-benefits may not only be reflected in the environmental situation, but can also generate economic and even social benefits.

This interrelationship among economy, society and environment eas not taken into account until the emergence sustainability concept. Sustainability policies focus on promoting the achievement of the Sustainable Development Goals (SDGs), which are a total of 17 specific targets that address global challenges in the three basic pillars: environmental protection, social development and economic growth.

Though the application of climate measures in the most “traditional” sectors is essential to reduce our environmental impact, both policy-makers and the society have realised that a deeper redesign of our daily habits is needed. As a result, new regulations are continuously promoted in order to shift consumption trends and even to implement new approaches to educate future generations.

Nevertheless, all that glitters in not gold and it should be borne in mind that sustainability and climate policy implementation might be a complex process that requires a careful planning and assessment of the expected effects. Therefore, how can policy-makers be sure to establish a measure if there is a possibility of further damage? This is where “Integrated Assessment Models” (IAMs) are introduced.

IAMs are analytical tools for assessing and estimating the impacts of diverse climate policies in various areas such as the economy, the environment or the social awareness, by selecting which sectors and regions to focus on. With these models, policies can make scientifically supported decisions to address climate change or they can use them to justify previous measures.

The usefulness of IAMs is immense as long as they are well-used, but if the right optimal conditions are not met, they can become simply incomplete representations of the future. The correct functioning of these models requires the effective involvement of politicians and other stakeholders in the IAM development stage, as well as the correct definition of the policy to be modelled (what is the issue to be addressed and the objective of its implementation, what is its spatial and temporal resolution, etc.). Once these conditions have been met, it is essential to ensure that the chosen policy and model are compatible, as not all IAMs have enough capacity to forecast the impact of such a measure, either because it does not include the sector of application, because the geographical location cannot be specified, or because the temporal horizon is too long to be considered by the IAM. Currently, the efforts are focused on creating IAMs with greater diversity and capacity to implement policies that are not only related to the economy, but also to social and environmental factors.

At CARTIF we have been actively involved in IAMs for a long time and, in fact, together with our colleagues at UVA, we have developed an IAM called WILLIAM. We are also involved in several European projects, such as IAM COMPACT or NEVERMORE, which aimed at improving the assessment, transparency and cosistency of models.