Resiliency-Oriented Economic Sizing of Battery for a Residential Community: Cloud versus Distributed Energy Storage Systems

The power supply resiliency of residential feeders against grid outages can be enhanced by installing battery energy storage (BES). Most of the previous studies used distributed BES (DBES) to increase resiliency of the feeders. The cloud BES (CBES) can also be used in a similar manner to improve resiliency. However, detailed modeling of optimal CBES sizing for resiliency improvement has not sufficiently been investigated in the literature. This paper formulates an optimization problem to determine the optimal CBES size to improve resiliency against grid outages. Both the number of outages and the outage durations are carefully incorporated into the problem. The results obtained by the proposed method with the optimal CBES size are also compared with those found for the optimal DBES size. It has been found that, for the studied feeder, the net present cost (NPC) of CBES decreased by 25.49% compared to its counterpart DBES. When the number of grid outages and/or the outage durations are increased, the CBES is found to be more economical than the DBES for all cases. For a budget limit of $750,000, the maximum interrupted demand is found as 39 kWh and 1,351 kWh for the CBES and DBES, respectively. When the budget limit is increased to M$ 1, the interrupted demand for the CBES is reduced to zero whereas the DBES still needs to interrupt a maximum demand of 805 kWh.