Resource Efficiency, Renewable Energy, and Energy Intensity: A Water–Energy–Food Nexus Perspective for South Africa

Abstract

The increasing pressure on water, energy, and food resources has created a need for integrated approaches to resource management, particularly in economies facing environmental and resource constraints. This study examines the relationship between resource efficiency and energy intensity in South Africa within the Water–Energy–Food Nexus framework. The analysis focuses on water productivity, water withdrawal intensity, electricity production from renewable sources, and cereal yield as interconnected resource-related determinants of energy intensity. Using annual time-series data from 1980 to 2025 obtained from the World Development Indicators database, the study applies the Autoregressive Distributed Lag approach to distinguish between long-run equilibrium relationships and short-run adjustment dynamics. Unit root results confirm a mixed order of integration, with variables stationary either at level or after first differencing and none integrated at the second difference. The bounds testing procedure establishes a long-run equilibrium relationship among energy intensity and the selected water, energy, and food variables. The long-run estimates indicate that water productivity and water withdrawal intensity are negatively associated with energy intensity, while electricity production from renewable sources has a positive association. Cereal yield also exhibits a negative long-run relationship with energy intensity. In the short run, renewable electricity production is positively associated with energy intensity, whereas water productivity has a negative relationship. The significant error correction mechanism confirms that short-run deviations adjust toward the long-run equilibrium. The findings demonstrate that resource systems in South Africa are dynamically interconnected and that changes in one component of the Water–Energy–Food Nexus can be associated with energy-use outcomes across different time horizons. The study contributes to the nexus literature by providing time-series evidence on the joint relationship between water efficiency, renewable electricity generation, agricultural productivity, and economy-wide energy intensity. The findings provide an integrated basis for resource governance that combines water-use efficiency, agricultural productivity, renewable energy development, and energy-efficiency strategies.