Optimizing urban solar photovoltaic potential expansion using top-down and bottom-up approaches: the example of Budapest

This study develops a spatially optimized solar photovoltaic (PV) expansion strategy for Budapest, Hungary, which aims to increase PV capacity from 200 MW to 1,500 MW by 2030 in line with its climate and urban development goals. Using an integrated top-down and bottom-up approach, the study combines GIS and LiDAR-based data with building typology analysis to assess technical feasibility and prioritize deployment. Results show that the raw technical PV potential of 5,000 MW reduced to 2,200 MW deemed realistically installable after spatial and regulatory constraints. Public institutions and prefabricated panel buildings offer the highest deployment efficiency, while World Heritage visibility restrictions reduce the potential by 170 MW. Two implementation scenarios (1,500 MW and 2,200 MW) highlight the importance of standardized installations and public sector involvement to reduce cost and time. The findings inform policy design by linking spatial planning, urban morphology, and economic feasibility, offering a replicable model for other EU Mission cities.