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Urban Nexus

Towards Productive Cities // Environmental Assessment of the Food‐Energy‐Water Nexus of the Urban Roof Mosaic

By Susana Toboso‐Chavero, Ana Nadal, Anna Petit‐Boix, Oriol Pons, Gara Villalba, Xavier Gabarrell, Alejandro Josa, Joan Rieradevall. Cities are rapidly growing and need to look for ways to optimize resource consumption. Metropolises are especially vulnerable in three main systems, often referred to as the FEW (i.e., food, energy, and water) nexus. In this context, urban rooftops are underutilized areas that might be used for the production of these resources.

The authors developed the Roof Mosaic approach, which combines life cycle assessment with two rooftop guidelines, to analyze the technical feasibility and environmental implications of producing food and energy, and harvesting rainwater on rooftops through different combinations at different scales. To illustrate, we apply the Roof Mosaic approach to a densely populated neighborhood in a Mediterranean city. The building‐scale results show that integrating rainwater harvesting and food production would avoid relatively insignificant emissions (13.9–18.6 kg CO2 eq/inhabitant/year) in the use stage, but their construction would have low environmental impacts. In contrast, the application of energy systems (photovoltaic or solar thermal systems) combined with rainwater harvesting could potentially avoid higher CO2 eq emissions (177–196 kg CO2 eq/inhabitant/year) but generate higher environmental burdens in the construction phase.

When applied at the neighborhood scale, the approach can be optimized to meet between 7% and 50% of FEW demands and avoid up to 157 tons CO2 eq/year. This approach is a useful guide to optimize the FEW nexus providing a range of options for the exploitation of rooftops at the local scale, which can aid cities in becoming self‐sufficient, optimizing resources, and reducing CO2 eq emissions.


Whiley online library


November 2018


Journal of Industrial Economy

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Modelling and Assessment

Nexus Modelling // Towards Ranking the Water–Energy–Food–Land Use–Climate Nexus Interlinkages for Building a Nexus Conceptual Model with a Heuristic Algorithm

By Chrysi S. Laspidou, Nikolaos Mellios and Dimitris Kofinas. In this article, a practical heuristic approach for gaining a systemic and contextual perspective on nexus component interlinkages is presented, by building on a simple three-point typology of interactions. The approach is simple and can be applied in any case study a nexus analysis is pursued, regardless of data availability.

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Nexus Blog

Un Nexus pour les Organismes de Bassin au Sahel // Comparaison multisectorielle : OMVS - CBLT - ABN

Par Luca Ferrini (Représentant Dialogues Mondiaux NEXUS (Eau-Energie-Sécurité Alimentaire) dans le Bassin du Niger) et Lucia Benavides. Cet article fournit une analyse comparative du niveau d'intégration des différents secteurs dans les missions de trois organismes de bassin du Sahel : l'Autorité de Développement du Bassin du fleuve Sénégal (OMVS), la Commission du Bassin du Lac Tchad (CBLT) et l'Autorité du bassin du Niger (ABN). Il met en outre l'accent sur différents domaines d'intervention...

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Nexus Blog

A Nexus for Basin Organisations in the Sahel // Multisectoral comparison: OMVS - LCBC - NBA

By Luca Ferrini (Project Manager, Nexus Regional Dialogue Programme Niger Basin) and Lucia Benavides. This article provides a comparative analysis about the level of integration of different sectors within the mission statements of three River Basin Organisations in the Sahel: the Senegal River Basin Development Authority (OMVS by its French acronym), the Lake Chad Basin Commission (LCBC) and the Niger Basin Authority (NBA). It further stresses different focus areas of the mission statements,...

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