Performance of Vertically Mounted Bifacial Photovoltaics on High-Rise Buildings in the Nordic Conditions

In urban environments, limited land availability creates the demand for PV system installation on buildings. Roof spaces are often used as the installation surface for conventional solar panel systems. In multi-story buildings, which have low roof area compared to building volume, the roof space can be too limited to host sufficiently sized PV systems. Adding PV on building façade to increase the total electricity production is a solution to the limited roof space in multi-story buildings. This study investigates the potential of installing vertically mounted bifacial photovoltaics (VBPV) on multi-story buildings in Helsinki, Finland (60°N). A five-story apartment building with different PV systems, modeled with commercial PVSyst software, is chosen as a case study. The result shows that VBPV on the facade has a lower specific production than rooftop monofacial photovoltaics (MPV), but their values are acceptable. The specific yield of VBPV on the facade is around 700 kWh/(kWpyear), while MPV on the roof is around 1000 kWh/(kWpyear). The percentage of increase in production by integrating VBPV on the facade depends on the amount of PV that can be installed on the roof, ranging from 126% to 7%. The comparison of facade-installed VBPV and MPV demonstrates that their total production is almost equal. MPV appears to be less complicated to install, while VBPV has the benefit of matching peak production with residential electricity consumption and occupying less facade space.