Solar energy landscapes in Nepal: site suitability analysis of solar photovoltaics using a geospatial multi-criteria decision analysis

Renewable energy deployment is expanding globally owing to rising environmental concerns, rising fuel costs and the need for long-term energy security. However, inadequate evidence-based knowledge and policies to support large-scale renewable energy deployment in developing nations like Nepal are hindering its penetration. Therefore, in this study, high-resolution spatial data in a geographical information system were paired with multi-criteria decision-making and an analytical hierarchy process to identify suitable sites for solar farm development in Nepal. This methodology employs criteria such as climate, economics, topography and environment to assess the spatial suitability of a solar farm. Results showed that only 3% of Nepal's land area is suitable for solar farms, with 1.32% (1798 km2) as highly suitable, 1.6% (2243 km2) as moderately suitable and 0.08% (124 km2) as least suitable. Suitable sites are concentrated in the Terai and hilly regions, reflecting optimal solar radiation, gentle slopes and proximity to infrastructure. Using these areas for solar installations would enhance Nepal's clean energy transition and help achieve its sustainable development goals. In summary, this study provides an analytical basis for the decisions of energy planners, government bodies, specialists and researchers involved in energy planning and policy formulation.