  Energy systems resilience is becoming increasingly important as the frequency
of major grid outages increases. In this work, we present a methodology to
optimize a behind-the-meter distributed energy resource system to sustain a
site's critical loads during a pre-defined utility outage period. With the
fixed system design, we then propose an outage simulation approach to estimate
the resilience potential of the DER system to sustain loads beyond the fixed
outage period - a yearlong resilience performance analysis. We apply
statistical analysis to assess the system's resilience performance over a
broader parametric problem space on an hourly, monthly, and yearly basis. We
present a case study to demonstrate the impact of the pre-defined outage period
on the resilience performance of the system. The case study shows that the
probability of surviving a random outage of a given duration changes from 20
percent to 95 percent when the outage is modeled for a weekday instead of a
weekend for the case study building.
