Diagnosing spatialized energy poverty traps: Global evidence from nighttime lights

• A 31-year harmonized NTL dataset tracks global functional electricity access. • 1.06 billion people lack functional access, revealing hidden energy poverty. • Spatialized Energy Poverty Traps (SEPTs) reveal zones of structural stagnation. • Kenya case study confirms grid densification alone fails to break deep traps. • Achieving SDG 7.1.1 requires accelerating growth by 37.5 times in marginal regions. Monitoring progress toward universal electricity access is hindered by a reliance on binary metrics that mask subnational and long-term stagnation. We derived a harmonized Electricity Access Indicator (EAI) dataset from satellite nighttime lights, validated against official benchmarks with Pearson correlation coefficients exceeding 0.82 at national and subnational scales, to track functional electricity usage from 1992 to 2022. We estimate that at least 1.06 billion people lacked functional access in 2022, a conservative lower bound that exceeds official figures and exclude communities too sparsely settled to register any detectable luminosity. Our analysis identifies Spatialized Energy Poverty Traps (SEPTs) as geographically entrenched zones where electrification has structurally stalled. We uncover a growth paradox where many rapidly developing low-income countries remain trapped due to strong path dependency and large initial deficits. Escaping these traps to achieve the 2030 sustainable energy targets demands an acceleration of up to 37.5 times current historical rates in marginalized regions. Policy assessment in Kenya confirms this methodology accurately separates regions suitable for grid densification from structurally isolated areas requiring decentralized deployment. This study shifts global monitoring from counting physical connections to diagnosing persistent spatial inequality. It offers a roadmap spatial decision rule for directing grid densification and off-grid investment where each is viable.