Evaluation of the Solar Energy Nowcasting System (SENSE) using Multiple Ground Based Measurements

Solar energy nowcasting is a  valuable asset in managing energy loads and having real-time information on solar irradiation availability. SENSE is an operational-ready system which exploits satellite retrieved images from the EUMETSAT’s Meteosat Second Generation for cloud microphysics information above a certain location, modelled aerosol optical properties data from the Copernicus Atmospheric Monitoring Service (CAMS), in conjunction with Radiative Transfer Model (RTM) simulations in order to retrieve the Global Horizontal Irradiance (GHI) and the Direct Normal Irradiance (DNI) spectrally (280 - 2800 nm). For a full year period (December 2020-December 2021) a campaign was held in Athens (Greece) in the framework of the “Atmospheric parameters affecting Spectral solar Irradiance and solar Energy” (ASPIRE) project. For the needs of the campaign a number of ground-based instruments were operating, including two pyranometers, a pyrheliometer, a cloud camera, a CIMEL sunphotometer, a BREWER and a PANDORA spectroradiometer and a Precision Spectral Radiometer (PSR).

In this study, we evaluate the integrated outputs of SENSE in W/m2, at 15-minute frequency against the ground-based recordings, for the period of the campaign. A separate assessment of the SENSE’s inputs (cloud and aerosol optical properties) is performed in respect to ground-based retrievals. Finally, deviations between SENSE and measurements are linked to deviations between climatological/satellite-based atmospheric parameters and those retrieved from the ground-based measurements. The detailed evaluation of SENSE inputs and outputs using detailed ground-based data advances our present-day knowledge about the uncertainties of SENSE products, thus improving our understanding of the renewable energy merit in the total energy use for Greece. This effort is important for SENSE users such as the Greek Independent Power Transmission Operator and the Public Power Corporation Renewable of Greece.