Power Outage Risk in Vermont

Vermont's outage risk is defined less by the grid itself than by the geography surrounding it. Green Mountain Power, the state's largest utility, serves roughly three-quarters of Vermont's customers. When Tropical Storm Irene hit in August 2011, the storm produced up to 11 inches of rain in 24 hours across the Green Mountains.

Rivers turned into floodways that destroyed over 500 miles of roadway and damaged or destroyed approximately 1,200 bridges and culverts. Thirteen communities were completely cut off, with no passable roads in or out. The National Weather Service documented nearly 50,000 power outages statewide. But the electrical grid was not the primary failure point. The real crisis was physical isolation: fuel deliveries, supply trucks, and utility crews could not reach stranded towns for days. Total costs from that single storm reached roughly 603 million dollars in federal outlays, 153 million in state and local expenses, and 63 million in insurance claims.

For backup sizing, Vermont's pattern inverts the usual calculus. The grid tends to recover fast, but road access does not. A portable station in a Vermont river valley needs enough stored capacity to operate independently until roads reopen, because resupply may not arrive for days.