Abstract
This study interrogates the energy reliability–productivity nexus in developing economies, with specific focus on Nigeria, where persistent power instability constrains productive performance despite expanded electricity access. The existing literature largely conflates electricity access with reliability, overlooking the distinct and conditioning role of supply quality in shaping productivity outcomes. To address this gap, the study employs a dual econometric framework combining ARDL bounds testing and the Toda–Yamamoto causality approach using annual data from 1990–2023. The results confirm a stable long-run relationship: electricity consumption significantly enhances productivity (elasticity = 0.428), while power unreliability exerts a substantial negative effect (−0.316). Causality runs unidirectionally from energy conditions to productivity, indicating a supply-constrained regime. Nonlinear and threshold analyses further reveal that productivity gains collapse beyond critical reliability thresholds. The study contributes by explicitly disentangling electricity consumption from reliability and providing robust causal evidence, establishing grid stability as the binding constraint on productivity in Nigeria.