It dawned on us that it’s been a while since we’ve had a power outage or phase imbalance requiring us to switch to generator power (although we do test every two weeks on load), so we did some digging and discovered that indeed the last time there was a utility power outage was back on October 24, 2010.
Over the last year we’ve only observed minor power flickering during weather and at least one lightening strike that caused a citywide (as observed by all of our remote monitoring points simultaneously) hiccup. All of these events where cleaned up by our online UPS system without going to battery.