Influence of aerosols pollution on the amount of collectable solar energy

The paper is focused on the estimation of collectable solar energy losses in aerosol pollution events. To do this, a parametric clear sky solar irradiance model has been built and validated. For applying the model, a set of four meteorological parameters (ozone, nitrogen dioxide, water vapor column content and the إngstrِm turbidity coefficient) are required at input. The energy loss in a pollution episode was evaluated as the difference between the clear sky solar irradiation computed in two situations: (1) Using measured values for all inputs and (2) using measured values for all inputs excepting the إngstrِm turbidity coefficient, for which a climatological reference value has been assumed. The calculations show that the aerosol pollution can lead to a significant loss of collectable solar energy, of over 20%. Overall results drive to the generic conclusion that the pollution episodes should be considered in both stages of a photovoltaic plant: in development, by taking them into account when the typical meteorological year is constructed, and in the exploiting stage, by accounting them in the forecasting procedure of the output power. The study was conducted with data collected in Timisoara, Romania, during 2011 and 2012.