This 2023 CISBAT conference paper assesses whether removing trees near a residential facade to reduce shading and increase BIPV output is justified from a life-cycle Global Warming Potential perspective (SGWP). Using Radiance ray-tracing irradiance maps, a temperature-sensitive single-diode PV model, parametrised BIPV arrays (18–36 configurations), and tree biomass/allometry growth models, the study compares scenarios across cell types (m-Si, p-Si, CIGS), module orientations, inverter types (central, string, micro), facade azimuths, four tree-planting scenarios, and three regional grid-carbon profiles (USA, DEU, FRA). Key findings: removing trees is not generally beneficial for SGWP (especially in low-Cgrid regions); CIGS systems tend to yield lower SGWP due to lower embodied carbon and relatively better low-light performance; inverter type and grid carbon intensity have larger impacts on S_GWP than nearby trees.
Questions this document answers
Justin McCarty (corresponding: mccarty@arch.ethz.ch), Christoph Waibel, Alina Galimshina, Alexander Hollberg, Arno Schlueter.
Journal of Physics: Conference Series (CISBAT 2023), 2600 (2023) 042002. DOI: 10.1088/1742-6596/2600/4/042002.
Monocrystalline (m-Si) 18.4%, Polycrystalline (p-Si) 16.3%, CIGS 15.3%.
Modules: m-Si = 246 kgCO2e, p-Si = 202 kgCO2e, CIGS = 68.9 kgCO2e. Inverters: central = 28.0 kgCO2e, string = 95.9 kgCO2e, micro = 96.8 kgCO2e.
DBH growth assumed 0.83 cm/year (Nowak et al. 2008).