Satellite‐Based Global Assessment of Solar Resource Stability

Abstract Satellite spatial smoothing complicates comparisons of solar variability between gridded products and point measurements. We introduce the Stability Deviation Index (SDI), a bounded composite of solar intensity and intraday variability. Applied independently to 69 BSRN stations and co‐located CERES grid cells, SDI shows strong cross‐platform agreement ( R = 0.89, mean bias ≈0). Applying SDI to 23 years of CERES satellite records (2001–2023) reveals an obvious climatic divergence: stable subtropical regions are becoming more stable, while coastal and equatorial zones are becoming more volatile. Overlaying SDI maps with global PV inventories reveals a systematic spatial mismatch between PV deployment patterns and climatic stability. Although utility‐scale plants are optimally located, over 70% of small‐scale distributed PV systems are deployed in highly volatile regions, particularly in China and India. Ultimately, SDI translates smoothed Earth observations into actionable, grid‐compatible intelligence, highlighting hidden systemic risks in modern solar deployment.