Satellite-derived assessments of surface downwelling solar irradiance are more and more used by engineering companies in solar energy. To increase performances, work is on going in the framework of the MACC project funded by the European commission, to improve both the modeling of the radiative transfer and the quality of the inputs describing the optical state of the atmosphere. The present study focuses on the cloudy atmosphere. EUMETSAT provides a range of products which could be potentially used for a proper description of cloud properties: cloud analysis, cloud analysis image, cloud mask. According to our study, the cloud products of EUMETSAT show a noticeable correlation with the ground measurements of solar irradiance. Nevertheless, these products are not suitable for an accurate assessment of the surface downwelling solar irradiance.