PNNL

Abstract

Numerical weather prediction (NWP), when accessible, is a crucial input to shortterm solar power forecasting. WRF-Solar, the first NWP model specifically designed for solar energy applications, has shown promising predictive capability. Nevertheless, few attempts have been made to investigate its performance under high aerosol loading, which attenuates incoming radiation significantly. The North China Plain is a polluted region due to industrialization, which constitutes a proper testbed for such investigation. In this paper, aerosol direct radiative effect (DRE) on three surface shortwave radiation components (i.e., global, beam, and diffuse) during five heavy pollution episodes is studied within the WRF-Solar framework. Results show that WRF-Solar overestimates instantaneous beam radiation up to 795.3 Wm-2 when the aerosol DRE is not considered. Although such overestimation can be partially offset by an underestimation of the diffuse radiation of about 194.5 Wm-2, the overestimation of the global radiation still reaches 160.2Wm-2. This undesirable bias can be reduced when WRF-Solar is powered by global atmospheric composition forecasts, which then translates to accuracy improvements in photovoltaic (PV) power forecasts. This work also compares the forecast performance with the European Centre for Medium-Range Weather Forecasts model. Under high aerosol loading conditions, the global radiation forecast accuracy generated by WRF-Solar increased by 53.2%, and the PV power forecast error was reduced by 6.8%.