A light in the dark: detectability of mini-grid electrification with remote sensing in sub-Saharan Africa

Abstract Satellite imagery is increasingly used to measure electrification rates and track progress toward the United Nations’ Sustainable Development Goals. However, its reliability in remote rural areas remains unclear due to sparse populations with far lower electricity consumption than urban areas. This study examines the detectability of electricity mini-grid installations through changes in nighttime brightness. We employed a difference-in-differences model adapted for staggered treatments on a dataset encompassing over 700 mini-grids built between 2014 and 2023 across 20 countries in sub- Saharan Africa. The findings indicate that mini-grids do not significantly alter the nighttime light signature immediately following installation, suggesting that traditional electricity access mapping techniques may underestimate electrification rates in rural areas. The analysis also uncovers a consistent and temporally varying background signal in visible infrared imaging radiometer suite day/night band nightlights that complicates the detection of brightness changes. Finally, two recent remote-sensing-based energy access maps are evaluated at known mini-grid sites: one identifies just 9% as electrified and the other 37%, consistent with our finding that mini-grid electrification is not fully detectable with current nightlight-based approaches. This study highlights the need for improved remote-sensing-based electricity access mapping techniques and, in lieu of that, bias correction for underestimations in rural areas.