Decentralised Water-Energy-Food (WEF) systems in Africa: Space analysis, least-cost modelling of sack farming and establishment of renewable energy technologies in the Diepsloot slums of Johannesburg, South Africa

Abstract

The African continent faces three distinct yet kindred problems: water, energy, and food security. Among the most vulnerable to water, energy, and food security are African cities’ poorest and most marginalised residents. Decentralised Water-Energy-Food (WEF) systems have been proposed to mitigate some of the damaging effects of climate change on energy, water, and food. While some scholars point out constraints related to decentralised WEF systems, working examples of novel decentralised WEF systems are cropping up globally. This paper demonstrates the potential of decentralised Energy-Water-Food systems in promoting access to food, water, and energy in informal settlements in Africa, focusing on Diepsloot slums of Johannesburg, South Africa. A mixed methods approach was adopted for the space analysis, least-cost modelling of sack farming, and establishment of renewable energy technologies in the Diepsloot slums of Johannesburg, South Africa. The methods include a review of literature, Geographic Information Systems (GIS), crop modelling with AquaCrop, financial analysis, and linear optimisation model urbs to identify the least-cost energy system design for the proposed community centre. Analysis of past rainfall, temperature, and climate trends; proposed water sources; spatial plant arrangements; proposed community centre; decentralised and renewable solutions; Phezulu ‘Up’ growers’ model; and a positive return on investment demonstrates the feasibility of the WEF model. Policymakers should promote decentralised Water-Energy-Food systems to enhance urban livelihoods and the achievement of Sustainable Development Goals (SDGs), in particular SDG 2 (zero hunger), SDG 6 (clean water and sanitation), and SDG 7 (affordable and clean energy), in marginalised African urban spaces.