Although we often think of blackouts as a summer emergency, they can happen during any time of year when power demand is higher than normal. Heat waves, cold snaps, and winter storms can all result in power outages. That’s because an increased use of heaters and air conditioners can put strain on the power supply. As energy usage approaches peak demand, utility companies may ask consumers to reduce their energy usage voluntarily to avoid a blackout. But in some cases, that isn’t enough, and regulators have no choice but to turn to rolling blackouts or load shedding as a last resort.