Energy self-sufficient households with photovoltaics and electric vehicles are feasible in temperate climate

System dimensioning for self-sufficiency The battery, hydrogen, and PV system dimensions required for full self-sufficiency (true zero energy buildings) and assuming 27.2% rooftop PV efficiency are given in Table 5. Since the fuel cell and electrolyzer sizes are fixed (4.8 kW in SFBs and 9.7 kW in MFBs for electrolyzers, 2.1 kW in SFBs and 4.1 kW in MFBs for fuel cells) they are not shown in this table. The bottom four multi-family cases marked with a � are those which consider our design limits for allowed PV area (i.e., they are outside the true zero energy boundary in Fig 3). The table illustrates that the key factor causing lower feasibility of self-sufficiency for both retrofitted houses and multi-family houses is that of limited rooftop space for PV, relative to demand: the SRCR case is the only single-family case that needs to add facade PV to fulfill its design requirements. While we also assume that the additional demand in retrofitted buildings is higher than that in new buildings, which makes these cases more difficult to begin with, it is this area limitation which is the key design parameter. Fig 3. Feasibility of achieving true zero energy and net zero energy requirements as quantified by the energy balance level achieved, and as a function of the scenario and rooftop PV module efficiency. Only the last two identifying letters for each scenario are shown for increased readability, with New/Retrofitted and Single/ Multi-family building given by the lines spanning the x-axis below the scenario labels. https://doi.org/10.1371/journal.pone.0227368.g003

Energy self-sufficient households with photovoltaics and electric vehicles are feasible in temperate climate PLOS ONE | https://doi.org/10.1371/journal.pone.0227368 March 4, 2020 12 / 25