Photovoltaic-Green Roof: A Review of Decarbonization, Cooling, and Ecological Performance, Key Factors, and Optimization Strategies

Photovoltaic green roof (PV-GR) which combines renewable power production with green roof (GR) is a promising solution. However, existing studies on PV-GR are limited and often focus on individual performance. Coupling mechanisms, main influencing factors, and their impacts on the overall performance of the PV-GR system remain unclear, limiting integrated design and optimization. This paper reviews recent progress in PV-GR research by outlining its integrated performance in power production, environmental cooling, ecological greening, and building energy conservation. It analyzes key factors, including meteorological conditions (e.g., ambient temperature, solar radiation, and rainfall), plant characterizations (e.g., transpiration, albedo, height), and PV module parameters (e.g., installation height, tilt angle, transparency, coverage ratio), and proposes optimization strategies. The paper proposes climate-specific strategies for different regions, including tilt angle adjustment, dynamic height changes, and plant selection based on local conditions. Moreover, existing studies show theoretical and methodological gaps of limited data from arid and continental climates, unclear system interaction mechanisms, and restricted research scope and duration. Future studies should focus on long-term field observations, explore system interactions, and develop integrated assessment tools to support the optimal deployment of PV-GR for sustainable urban development.