Dual aerosol events hit PV output across Southern Europe and North Africa

Irradiance across the Mediterranean region has taken a significant hit over the past week as atmospheric particulates from both Saharan dust and Canadian wildfire smoke disrupted solar conditions, according to analysis using the Solcast API. The combination of regional and transcontinental aerosol transport events has affected solar PV generation across Southern Europe, with reductions in irradiance and increased soiling.

The first major event unfolded with a surge of Saharan dust reaching into the mid-levels of the atmosphere, driven by a robust subtropical ridge that directed a deep southwesterly flow across the Western Mediterranean. On 16 May, this initial pulse of dust made its presence felt over Greece, where irradiance dropped by 5% to 7%. Analysis conducted by the Solcast Data Science team separates out the irradiance lost to aerosols and cloud, highlighting the impact of dynamic aerosols on solar generation. Total calculated global horizontal irradiance (GHI) lost to aerosols at a location in Rhodes was 251.5 kWh/m2 on the 16th of May. This detailed analysis was completed using the latest available higher-temporal-resolution satellite data from the Meteosat Third Generation satellite platform.

Beyond reduced irradiance, these dust events deliver a secondary complication: soiling of PV panels. Dust deposition, especially when brought down by rain, can significantly degrade panel efficiency and increases maintenance requirements. The persistent atmospheric ridge played a key role in steering this dust northward from the Sahara, enhancing its reach and duration over populated regions.

Following this event last week, a second Saharan dust cloud has been bolstered by smoke from wildfires in Manitoba, Canada. These fires produced pyrocumulonimbus clouds that propelled smoke high into the upper atmosphere, where strong westerly winds carried it across the Atlantic. Modelled aerosol optical depth (AOD550) data from CAMS depict the simultaneous progression of this smoke plume with the Saharan dust front approaching Greece.

This second event is visible in GHI anomaly data. In the below clear sky GHI anomaly analysis of the 18th of May, you can see smoke aerosols combine with a new dust cloud over the Iberian Peninsula and Morocco. This cloud then impacted Italy on the 20th, and reached Croatia, Hungary, and parts of the Greek Islands by the 21st. Solcast clear sky irradiance modelling from 18 May highlights the passage of this aerosol-laden air mass, with clear sky irradiance estimated to have dropped by around 5% in impacted areas. This degradation not only curtailed PV production but also raised the risk of soiling, particularly in areas that experienced rainfall during the aerosol intrusion.

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