Unleashing the green potential: Assessing Hong Kong's building solar PV capacity

The global shift towards renewable energy highlights the significance of building photovoltaic (PV) systems as a sustainable solution. Assessing a building's solar PV potential is essential for advancing green energy initiatives. This study establishes an integrated system for analyzing both roofs and facades, incorporating physical, geographical, and technical dimensions. Utilizing the Perez model for solar irradiance, Hillshade analysis for shading effects, and Ladybug tools for facade obstruction simulation, we assess the PV potential and its spatial-temporal variations across 180,349 buildings in Hong Kong. The results show that Hong Kong's roofs and facades have a physical potential of 4.00 × 1013 Wh and 2.48 × 1014 Wh, respectively. The feasible installation areas are identified as 14.44 km2 for roofs and 71.31 km2 for façades, yielding geographical potentials of 1.48 × 1013 Wh and 3.44 × 1013 Wh. Based on this, the estimated installed capacities are 1.27 GW for roofs and 12.75 GW for facades, which could generate between 2.07 × 1012–2.66 × 1012 Wh and 3.61 × 1012–4.65 × 1012 Wh, respectively. These projections account for 12.68%–16.32% of Hong Kong's total electricity consumption in 2022. This study underlines the substantial role of building-integrated solar PV systems in Hong Kong's transition towards a low-carbon future, offering valuable insights for policymaking and implementation strategies.