Residential Battery Storage System Sizing for the Medically Vulnerable from the Life Continuity Planning Perspective: Toward Economic Operation Using Uncertain Photovoltaic Output

Business continuity planning (BCP), which achieves a sustainable power supply for essential appliances under large-scale disasters, is an important concept for hospitals. Similarly, life continuity planning (LCP) was developed in the housing field. It assists medically vulnerable people who require continuous use of medical equipment in their homes because a failure of the LCP during power outages causes serious problems. If PV systems are used, storage batteries would be most fitting to economically implement LCP during normal situations. This can be achieved by effectively utilizing PV power generation. Here, the installation of an appropriate battery capacity is crucial. Considering the uncertainty of PV power generation owing to weather conditions, appropriate sizing of the battery capacity maximizes the expected economic benefits while leaving a margin LCP implementation. We discuss uncertainty of PV power generation at a residential site by applying the envelope-bound model (EBM), which is popular in information gap decision theory, and proposed a sizing method for a battery storage system that economically achieves LCP. We performed a case study to prove that the proposed method, which considers the uncertainty in the expected PV output based on EBM, can be an efficient decision-making tool to select an appropriate battery size.