Optimization of urban resources efficiency in the domain of water-energy-food nexus through integrated modeling: a case study of Addis Ababa city

This study aims to understand the long-term (2020-2050) urban water-energy-food (WEF) resources access and sustainability in Addis Ababa city through a nexus modeling approach. Several feasible scenarios in line with improving WEF resources supply and access through conservation, system rehabilitation and technology input are explored. The water system scenarios include rehabilitation and conservation scenario, water supply enhancement scenario, technology input scenario and integrated water improvement scenario. The energy scenario includes energy conservation scenario and new renewable supply enhancement scenarios and integration of both scenarios as integrated energy scenario. The food system scenarios include crop yield productivity and irrigation water use efficiency scenarios of urban agricultural system. The integrated WEF nexus scenario is the integration of all scenarios under one nexus framework. The results are evaluated against baseline scenario. At a system level, the integrated water scenario result provides a water saving potential of 26 and 52% from the baseline scenario by 2030 and 2050, respectively, whereas the integrated energy use scenario saves energy by as much as 22 and 48%. For respective years, under the integrated WEF nexus scenario, the integrated water use scenario for low energy intensity reduces the energy use for urban water system by 23 and 72% from the baseline scenario. Similarly, urban food production have also shown enhancement. Urban food production system in Addis Ababa city is relatively small and does not significantly affect the food import from other parts of the country. Overall, the results WEF nexus modeling approach revealed the importance of exploring integrated nexus approach to sustainable urban water energy and food development and management as a first attempt at the urban scale.