Battery, Portable or Standby Generator? It Depends on How Long Your Outages Last

Two numbers that do not move together

A grid can go out often but come back fast, or go out rarely and stay out for hours. In this year's filings, 79 utility-state records had outage counts in the worst quarter nationally but outages shorter than the 120-minute median; 32 had outage counts in the best quarter but outages longer than 175 minutes. Those two groups need opposite kinds of backup.

Short outages: a battery is enough

When a typical outage is under about 120 minutes, a battery power station covers a fridge, router and lights until power returns, with no fuel, fumes or start-up. 453 reporting records fall in this group.

Moderate outages: a portable generator

Between about 120 and 175 minutes, a small battery starts to run out before the grid comes back, and a fuel-powered portable generator is the better match. 227 records fall here.

Long outages: standby

Past about 175 minutes per outage - the longest quarter nationally - continuous fuel matters more than stored capacity, which is where a permanently installed standby generator on natural gas or propane earns its cost. 227 records fall here. Remember these are averages: a utility with a moderate average can still leave you dark for days after a major storm.

Where to go next

See the range across large utilities: Great Lakes Energy Coop, MI, Evergy Missouri West, MO, Nashville Electric Service, TN.

Why Rural Co-ops Lose Power More Often Than City-Owned Utilities · Why One Big Storm Can Make a Utility Look Unreliable