Solar PV Site Selection Using GIS-MCDM: A Comprehensive Approach with Spatially Explicit Collinearity and Sensitivity Analyses

The strategic siting of large-scale photovoltaic (PV) power plants is crucial for optimizing energy production while minimizing environmental and socio-economic conflicts. This study employs a Geographic Information System (GIS) integrated with Multi-Criteria Decision-Making (MCDM) to develop a suitability model for PV site selection in the Lombardy region of Italy. A comprehensive set of environmental, technical, and infrastructural criteria was considered using the Analytical Hierarchy Process (AHP). To enhance the robustness of the model, spatially explicit multicollinearity analysis was applied to identify intercorrelation factors, ensuring the independence of criteria. Additionally, sensitivity analysis was conducted to assess the impact of weight variations on site suitability classification, revealing the relative stability of different suitability classes. Results indicate that only ∼25% of Lombardy is available for PV development after applying exclusion constraints, with the highly suitable class covering 40.5% of this area. Sensitivity analysis revealed that distance to substations and terrain aspect were the most influential factors, while stability assessment showed that 96.7% of the “most suitable” areas remained unchanged under ±10% weight variations. The inclusion of albedo further improved site evaluation for bifacial PV modules. Compared to conventional GIS–AHP suitability studies, the proposed framework advances PV site assessment by explicitly addressing criterion interdependence and spatial robustness, thereby providing more reliable and policy-relevant suitability outcomes in highly regulated regions. The proposed GIS-MCDM framework provides a systematic and adaptable approach for regional-scale solar energy planning, offering valuable insights for policymakers and energy developers.