Beyond Renewable Energy Targets: Understanding the Land Use Implications of Solar Energy Facilities in Continental Portugal

The growing demand for land to accommodate renewable energy infrastructure has intensified competition with biodiversity conservation, agriculture, and ecosystem services. In Portugal, electricity system decarbonisation relies heavily on utility-scale solar energy (USSE) facilities, yet the spatial extent of land transformation associated with photovoltaic development has not been systematically assessed. This study provides an assessment of the land occupancy of USSE facilities and associated land use and land cover (LULC) changes in continental Portugal over the past two decades, as well as their spatial relationship with areas designated for land and nature conservation. A geospatial database of USSE installations (≥1 MW) was developed through the integration of multiple data sources using geographic information systems (GIS). The geometric consistency of spatial features was ensured through harmonisation and validation procedures involving GIS-based corrections supported by Sentinel-2 satellite imagery. Spatial overlay analyses were conducted with multitemporal LULC datasets and with land-use planning constraints, including areas classified for nature conservation, ecological reserves, and agricultural reserves. The results indicate that USSE deployment has been predominantly located in the southern regions of Portugal, although the location of planned projects indicates a northward shift. The implementation of USSE facilities has been mainly associated with LULC changes in forest land, agricultural areas, pastures and shrubland. Spatial overlaps were observed with areas classified within the national ecological and agricultural reserves. These patterns may be indicative of growing land-use conflicts, but the extent to which these developments align with land-use planning objectives and conservation priorities requires further examination.