Assessing electrical bottlenecks at feeder level for residential net zero-energy buildings by integrated system simulation

Recent European communications focus on the enforcement that by 2020 all new buildings are nearly Zero-Energy Buildings (ZEBs) and on the deployment of a European Smart Grid. The presented work focuses on assessing the electrical challenges at neighborhood level of an building stock evolving towards ZEBs, and identifying the resulting challenge in multidisciplinary dynamic simulation models required to perform this assessment. A tool for Integrated District Energy Assessment by Simulation (IDEAS) is developed. This IDEAS tool allows simultaneous transient simulation of thermal and electrical systems at both building and feeder level. Residential ZEBs show a self-consumption of locally generated photovoltaic (PV) electricity of 26 +/- 4% at building level. Resulting feeder voltage fluctuations and possible transformer overload are quantified as bottlenecks. When all dwellings are intended to achieve a ZEB status, (i) a fraction of 14-47% of local PV supply is wasted by inverter curtailing depending on the feeder strength, while (ii) the peak transformer load is found to be 3.3 kVA per dwelling which may affect power security in existing feeder designs. (C) 2012 Elsevier Ltd. All rights reserved.