The Aspire campaign: Assessing the effects of aerosols on solar radiation and energy in SE Europe.

<p>In recent years, solar power applications are growing rapidly worldwide, to meet the increasing power demand and the sustainable development planning. Estimation of solar radiation availability at surface level, its characteristics and various factors that affect it, play a key role in designing and achieving the optimal performance of systems employing solar energy. Various solar -PV related - applications are using radiative transfer modeling to characterize the radiation field, since accurate surface solar irradiance measurements are not always available, especially in remote regions. Understanding the effect of aerosols to the solar energy potential is highly important for the energy sector as well as for a variety of fields. &#160;&#160;&#160;In areas and periods where cloudiness is limited and they are in the proximity of particle sources, the significance of aerosol effect is very high.</p> <p>The objective of this study is to assess the impact of the variability of aerosols on the solar Direct Normal Irradiance (DNI), Global Horizontal Irradiance (GHI) and solar energy, using spectral solar measurements and aerosol optical properties retrievals, in the framework of the one-year experimental campaign (December 2020-December 2021) of the ASPIRE (Atmospheric parameters affecting SPectral solar IRradiance and solar Energy, https://aspire.geol.uoa.gr) project, which was held in Athens, Greece.</p> <p>Main findings include an assessment of differences among different PV technology and their calculated outputs using actual and standard spectra, linking the differences with aerosol optical properties (optical depth, spectral dependence, absorption). Aerosol optical depth is the major factor of such differences for all PV technologies. Spectral aerosol characteristics affect differently PV technologies as a consequence of different spectral responsivities.</p> <p>Finally, aerosol effect on solar nowcasting models have been investigated by comparing spectral solar measurements and aerosol properties with model inputs and outputs.</p>