Evaluating the Performance of WRF-Solar Model for 72-Hour Ahead Global Horizontal Irradiance Forecasting in West Africa: A Case Study of Ghana

Abstract

Accurate forecasting of solar irradiance is crucial for the integration of solar energy into thepower grid, power system planning, and the operation of solar power plants. The WeatherResearch and Forecasting (WRF) model, with its solar radiation (WRF-Solar) extension, hasbeen used to forecast solar irradiance in various regions worldwide. However, the applicationof the WRF-Solar model for global horizontal irradiance (GHI) forecasting in West Africa,specifically in Ghana, has not been studied. This study aims to evaluate the performance ofthe WRF-Solar model for GHI forecasting in Ghana, focusing on 3 health centers (Kologo,Kumasi and Akwatia) for the year 2021. We applied a two one-way nested domain (D1=15km and D2=3 km) to investigate the ability of the WRF solar model to forecast GHI up to 72hours in advance under different atmospheric conditions. The initial and lateral boundaryconditions were taken from the ECMWF operational forecasts. In addition, the optical aerosoldepth (AOD) data at 550 nm from the Copernicus Atmosphere Monitoring Service (CAMS)were considered. The study uses statistical metrics such as mean bias error (MBE), root meansquare error (RMSE), to evaluate the performance of the WRF-Solar model with theobservational data obtained from automatic weather stations in the three health centers inGhana. The results of this study will contribute to the understanding of the capabilities andlimitations of the WRF-Solar model for forecasting GHI in West Africa, particularly inGhana, and provide valuable information for stakeholders involved in solar energy generationand grid integration towards optimized management of in the region.Keywords: WRF-Solar; Global horizontal irradiance; Forecasting; West Africa; Ghana