Uncovering South Sudan's renewable energy potential: a comprehensive evaluation of favourable locations and variability

South Sudan is a landlocked country in East-Central Africa. It faces significant energy challenges, with only 7% of the population having access to electricity. Its dependence on biomass and diesel fuel has increased deforestation and air pollution, leading to environmental and health issues that endanger the environment and public health. The aim of this study is to assess the potential, suitability, and seasonal variation of renewable energy sources, with a focus on wind and solar power. The motivation for this research is South Sudan's urgent need to diversify its energy resources, reduce its reliance on fossil fuels, and address the energy demand while mitigating environmental degradation. This study includes a historical analysis of the daily wind and solar data collected over a period of 40 years (1974–2014) at four meteorological stations in South Sudan. The monthly wind speed and direction distributions, wind power density and monthly sunshine duration and solar radiation are computed. XLSTAT 2023, Tubular, Google Sheet, and the Angstrom–Prescott model are used to analyse and estimate the wind power density and solar radiation. The results show the variations in wind speed, power density, and solar radiation at the chosen locations. The wind-energy potential varies across the sites, with Malakal and Juba showing the highest annual average wind power densities—114.09 W/m2 and 115.17 W/m2, respectively—placing them in Class 3 (“Fair”). These are complemented by seasonal peaks of 373.31 W/m2 (January, Malakal) and 220.16 W/m2 (April, Juba), indicating strong suitability for medium-scale wind systems. Wau and Raga, with lower annual averages (88.32 and 58.07 W/m2), fall into Class 2 (“Marginal”) but may be able to support small-scale or hybrid solutions. Wind-direction patterns vary, requiring tailored micro-siting strategies. Solar resources exhibit greater consistency, with annual solar radiation averages between 19.56 and 19.72 MJ/m2/day across all sites, classifying them under “Moderate Solar Radiation.” Seasonal peaks of 22.22 MJ/m2/day in Wau (September) and 21.62 MJ/m2/day in Raga, place certain months in the “High Radiation” category, reinforcing the possibility for diverse solar technologies and hybrid systems. This quantitative assessment offers clear perspectives into the renewable-energy landscape of South Sudan, emphasizing the potential of solar and wind energy to address the country’s energy crisis. The findings provide a foundation for policymakers and investors to strategically develop wind and solar projects aligned with the global sustainable development goals, particularly SDG 7 (affordable and clean energy), SDG 13 (climate action), and SDG 9 (industry, innovation, and infrastructure), which foster economic growth and reduce the dependency on fossil fuels.