Estimation of Solar Energy Resource From Digital Elevation Model Across Heterogeneous Landscapes of Zimbabwe

Information on the spatial variation of solar radiation is essential for sustainable solar energy planning. This paper models average monthly and annual solar radiation across Zimbabwe using a 30 m Shuttle Radar Topographic Mission (SRTM) digital elevation model (DEM). The spatial analyst tool was used to compute solar radiation from DEM for specific areas based on their potential for hosting solar plants. Multiple statistical model evaluation metrics namely Pearson correlation ( R ), coefficient of determination ( R 2 ), mean absolute error (MAE), root mean square error (RMSE), standard deviation of residual (SD) and Willmott’s index of agreement (WIA) were computed to validate the performance DEM derived radiation and National Aeronautics and Space Administration–Prediction of Worldwide Energy Resources (NASA‐POWER) data against ground radiation measurements. The study further developed regression equations for respective areas across the country. Results show that modelled radiation was highly and positively correlated with measured radiation ( R > 0.71, RMSE < 0.5 kWh/m 2 and MAE < 0.7 kWh/m 2 ). Furthermore, results illustrates that Zimbabwe has high potential for solar energy with an annual average radiation ranging between 4.6 and 6.6 kWh/m 2 . The study demonstrates the increasing role of geospatial analysis in solar energy planning.