• Indirect cirrus effects of Saharan dust cause major PV losses. • High dust and dense cirrus clouds yield the lowest observed solar performance. • Dust alone has reduced impact; cirrus amplification drives strong irradiance loss. • Bootstrap analysis shows dust reduces PV performance ratio mainly via cirrus cloud enhancement. Saharan dust outbreaks increasingly affect Europe, yet their full impact on photovoltaic (PV) performance remains insufficiently represented in models. We investigate Saharan dust events over Hungary, a country with the highest share of PV-based electricity generation (2024: 25%). Using 2019–2024 PV production for Hungary, combined with MERRA-2, MODIS and CAMS datasets, we show that the dominant losses arise not from the direct radiative attenuation of dust, but from dust-induced enhancement of cirrus clouds, which substantially increases atmospheric extinction. Across the study period, PV performance ratio during high-dust and high-cirrus conditions fell to 46%, compared to > 75% on low-dust days. Cirrus reflectance increased by 55%, and cirrus coverage by 60–85% during high-dust episodes, highlighting a robust aerosol-cloud interaction (ACI) signal. Seasonal analyses reveal that these indirect impacts peak in the transitional seasons (spring and autumn), when thermodynamic conditions favour heterogeneous ice nucleation. In these seasons, PV performance ratio exhibits a clear sensitivity to dust load (R 2 ≈0.94–0.96), and cirrus optical thickening is most pronounced. Bootstrap-based mediation analysis also demonstrates that the dominant impact of dust on performance operates indirectly through dust-induced cirrus enhancement rather than through direct aerosol attenuation alone. This study provides the first quantitative separation of direct dust effects and cirrus-mediated indirect pathways in national-scale photovoltaic performance, revealing that ACI dominate PV losses during dust intrusions. By moving beyond correlation-based analyses, it introduces a transferable, statistically robust framework for diagnosing dust impacts on solar energy systems under real-world operating conditions.
Varga et al. (Wed,) studied this question.