As urbanization progresses rapidly, cities encounter significant environmental and energy challenges. Photovoltaic-Green Roof (PV-GR) technology offers an innovative strategy with the potential to alleviate urban carbon emissions and resource scarcity issues. However, the carbon reduction potential of PV-GR technology remains unclear. Hence, this study aims to comprehensively assess the carbon reduction potential of PV-GR. This is achieved by integrating Geographic Information Systems (GIS), lifecycle assessment, the Denitrification-Decomposition Model (DNDC), and solar simulation. Using Fuzhou City as a case study, the research indicates: (1) Fuzhou has approximately 72.9 km of rooftops suitable for PV-GR development, with an annual biomass production from herbaceous plants estimated at around 2.958 × 10 kg. The annual electricity production under the baseline scenario reaches 9,678 GWh, satisfying about 17 % of Fuzhou’s annual electricity demand. Moreover, in an optimistic scenario, electricity generation rises to 10,176 GWh, and even in a pessimistic scenario, it could achieve 9,471 GWh. (2) In the baseline scenario, Fuzhou’s PV-GR annual carbon reduction is estimated at 6.678 × 10 t CO, potentially offsetting about 11.14 % of the city’s annual carbon emissions. In an optimistic scenario, this reduction increases to 7.022 × 10 t CO, and even in a pessimistic scenario, the reduction remains significant at 6.535 × 10 t CO. (3) Over a 30-year lifecycle, the carbon emissions from PV-GR are projected to total 3.092 × 10 t CO, accounting for 51.34 % of Fuzhou’s annual emissions. In an ideal baseline scenario, the net carbon reduction over the lifecycle of PV-GR could total 1.703×10 t CO, effectively offsetting 282.76 % of Fuzhou’s annual carbon emissions. Additionally, scenario simulations suggest that by 2030, potential electricity generation from PV-GR could increase to between 10,463 GWh and 10,901 GWh, due to changes in power structure and urban expansion. Overall, this study demonstrates that PV-GR holds considerable potential for carbon reduction.

中文翻译：

---

绿色能源和屋顶创新：释放光伏绿色屋顶的碳减排潜力


随着城市化的快速发展，城市面临着巨大的环境和能源挑战。光伏绿色屋顶（PV-GR）技术提供了一种创新策略，有望缓解城市碳排放和资源稀缺问题。然而，PV-GR技术的碳减排潜力仍不清楚。因此，本研究旨在全面评估PV-GR的碳减排潜力。这是通过集成地理信息系统 (GIS)、生命周期评估、反硝化分解模型 (DNDC) 和太阳模拟来实现的。以福州市为例，研究表明：（1）福州市适合光伏GR发展的屋顶面积约为72.9平方公里，草本植物年生物质产量约为2.958×10 kg。基准情景下的年发电量达到9,678 GWh，可满足福州约17%的年电力需求。此外，在乐观的情况下，发电量将升至10,176 GWh，即使在悲观的情况下，发电量也可能达到9,471 GWh。 (2) 在基准情景下，福州光伏GR年碳减排量预计为6.678×10 t CO，可抵消该市年碳排放量的11.14%左右。在乐观情景下，这一减排量将增加至 7.022 × 10 t CO，即使在悲观情景下，减排量仍然显着，为 6.535 × 10 t CO。 (3) 在 30 年的生命周期中，PV-GR 的碳排放量预计二氧化碳排放总量为3.092×10t，占福州市年排放量的51.34%。在理想的基准情景下，PV-GR整个生命周期的净碳减排总量可达1.703×10 t CO，有效抵消福州年碳排放量的282.76%。 此外，情景模拟表明，到 2030 年，由于电力结构的变化和城市扩张，PV-GR 的潜在发电量可能会增加到 10,463 GWh 至 10,901 GWh 之间。总体而言，这项研究表明PV-GR在碳减排方面具有巨大的潜力。