West African operational daily solar forecast errors and their link with meteorological conditions

West Africa is at the forefront of global environmental challenges with its commitment to reduce greenhouse gas emissions and harnessing the potential of renewable energy, especially the promising solar power. This study evaluates Global Horizontal Irradiance (GHI) operational forecast errors for the Zagtouli (Burkina-Faso) and Sococim (Senegal) solar plants, and investigates their links with local meteorological conditions, particularly clouds and dust aerosols. Firstly, the evaluation of aerosol products indicates that CAMS reanalysis is reliable for assessing aerosol optical depth. We then examine the accuracy of three operational GHI forecast products: the Global Forecast System (GFS, NCEP), the Integrated Forecast System (IFS, ECMWF), and SteadyMet (SM, French company Steadysun). The analysis reveals that IFS and SM outperform GFS, SM having a slight advantage due to its probabilistic nature. Closer examination reveals a significant relationship between GHI forecast errors and local meteorological characteristics. These errors are more pronounced during the wet season, primarily attributed to cloud occurrence. Dust events play a secondary influential role, especially during the dry season. Correlation analyses emphasize the forecast errors' major link with cloudiness, while co-occurrences highlight that dust aerosol is a secondary factor in forecast errors for the GHI directly or for cloud representation (aerosolcloud interaction).