Estimating Solar Energy Potential in the High-Altitude Region of Jumla, Nepal, using RadEst 3.0 ver. Software

Solar energy, a clean, renewable, and sustainable resource, has become a key energy alternative in the 21st century. Despite its global availability, over 70% of Nepal’s energy still comes from conventional sources, emphasizing the need for solar energy assessments. Situated within the global solar energy belt, Nepal has significant potential for solar power utilization. This study evaluates solar energy potential in Jumla (29.28°N, 82.16°E, 2300 m altitude), a mid-western mountainous region of Nepal. Meteorological parameters were processed using RadEst 3.0 software, which applied auto-optimization and parameter-fitting techniques to estimate solar radiation. Predicted values were validated against observed data using four empirical models: Bristow and Campbell (BC), Campbell and Donatelli, Donatelli and Bellocchi, and the Modular DCBB model. The BC model demonstrated the best performance, yielding higher radiation estimates with lower mean bias error (MBE), root mean square error (RMSE), and coefficient of residual mass (CRM). The annual average solar energy was 18.9 MJ/m²/day in 2021, 19.3 MJ/m²/day in 2022, and 19.6 MJ/m²/day in 2023, with RMSE values of 3.76, 3.81, and 3.99 MJ/m², respectively. These results confirm the BC model’s reliability and its applicability for solar energy prediction in similar regions of Nepal.