Self-sufficiency in Mid- to High-Rise Buildings with Photovoltaic Façades

For mid- to high-rise buildings to be self-sufficient in their energy use, both roof and façades are necessary for the local harvesting of solar energy. In this paper a generic model is described that allows the calculation of energy generation by building integrated or building applied photovoltaic (PV) systems and compares that to the energy demand of the building. Self-sufficiency ratios can be calculated as well. Typical energy demands for mid- to high-rise buildings are reviewed to find a typical range in energy demands, for future fully electrified buildings, using heat pumps for heating. An example building is used to show the effects of building energy demand, the number of floors, the efficiency of the façade PV systems, and the location of the building in Europe on self-sufficiency ratios. Self-sufficiency ratio values of 1 or higher can be obtained for buildings with 50 kWh/m2 annual energy demand, with 5–25 floors and half of the façades and roof covered with PV.