Photovoltaic Power Plants (PVPP) are a renewable energy source that use solar panels to transform sunlight into electricity. Identifying optimal locations for PVPP is essential to ensure the site meets numerous criteria and leads to maximised energy production. Mountainous terrains can often be overlooked as PVPP candidates because they are deemed as difficult or unsuitable areas. However, with proper installation techniques and site selection, these areas can offer high functionality and energy output. Despite its potential and growing relevance, there remains a lack of a practical framework for selecting optimal PVPP sites.

This study developed and applied a model for selecting optimal locations for installation of PVPP in mountainous terrains, using the Republic of North Macedonia as a case study. By employing geographic information systems (GIS) combined with multi-criteria decision analysis (MCDA) and the analytic hierarchy process (AHP), various criteria for selecting optimal locations were considered. Nine key factors and additional six constraints were evaluated, with expert insights used to define the criteria and determine AHPweightings. The model identified over 5,720 km² of highly suitable land in the study area, while 11,831 km² were excluded based on the applied constraints. The Vardar, East, Southeast and Pelagonia regions were classified as highly suitable. Energy production was calculated for several locations, confirming a successful PVPP siting with approximately 1.6 GWh/year energy output for an area of 10,000 m².

This study offers a transferable decision-support framework for sustainable energy planning in mountainous terrains, contributing to North Macedonia’s renewable energy transition goals and the European Union’s clean energy agenda.