Global Analysis of Combined Photovoltaic Green and Cool Roofs Under Climate Change

Abstract

Sustainable roofing configurations, including green and white roofs, can reduce rooftop surface temperatures compared to conventional surfaces and can therefore enhance photovoltaic (PV) system performance due to the temperature dependence of PV cells. Previous research, primarily experimental, recognized the synergy of combining PV with green or cool roofs. However, the influence of geographic and climatic factors on the performance of these combined systems, particularly in future climates affected by climate change, remains unclear. This work integrates three roof configurations (gravel, green, and white) into rooftop solar energy modeling across thirteen cities with different climate types, under current and future climate scenarios. Results indicate limited efficiency gains (< 2%) across all cities and climates, challenging previous findings. Yield is expected to increase in some cities receiving more solar irradiation in the future but decrease in others due to rising temperatures. Green and cool roofs can partially offset the effects of climate change on yield. PV-white roofs consistently outperform PV-green roofs, with the performance gap expected to widen in future climates. PV-green roofs excel in tropical climates with high irradiation and precipitation levels. Overall, the outcomes of this study inform the design and planning of sustainable buildings in response to climate change challenges.