Solar energy for multi-story apartment buildings-Innovative façade solutions and energy sharing enable load-matching

This study provides novel insights on increasing the profitability of solar photovoltaic (PV) systems in Nordic urban areas via innovative façade solutions and internal electricity trade in a multi-story apartment building. Nordic PV is growing fast, and the low solar elevation makes various facade installations attractive, but the insight on their impacts on energy economics of apartment buildings is lacking, and this research gap is addressed in this study. Besides conventional rooftop PV, this work investigates innovative vertical bifacial PV (VBPV) façade solutions that allow improved load-matching. Such matching of daily PV profile to load is an unusual approach compared with demand response and energy storage. Investigating the economic value of PV generation with real electricity price data and a large set of real apartment consumption profiles from southwestern Finland and different energy sharing scenarios in building- and apartment-levels provide additional novelty. In addition, investigating different real shading scenarios as well as the impact of exact building orientation provides robustness. The key results show that energy sharing corresponds to 13–14% of the total PV production and provides a 10–12% increase in the value of the produced PV electricity with a small (12-panels, 5.28 kW) rooftop PV system and different façade systems. Buying electricity from the intra-building market is beneficial for the apartment owner. The shading reduced PV production by 5.6–8.3% with minor shading, whereas non-optimal building orientation had a limited impact on the PV electricity value giving freedom to the practical building design.