Temporary power outages, called rolling blackouts, are a tool energy companies use to manage power grids when supply and demand fall out of balance. Cutting power in a controlled and brief manner protects sensitive equipment from being overloaded and allows utilities to carefully bring systems back into supply-and-demand harmony.

Here are all the details to know, starting with the answer to the question: What is a rolling blackout? We will conclude with some tips for how you can prepare for rolling blackouts and help prevent them.

What is a rolling blackout?

Utility companies may initiate a series of temporary power shutdowns when demand becomes so much higher than supply that equipment is put at risk of serious damage. By carefully cutting power to first one part, then another part of the city or region for a few hours, the power company can limit demand for power and protect against overloads.

A rolling power outage allows the available energy supply to be shared among customers. It also protects sensitive sites like hospitals, from power loss. If the grid was not protected against these potential overloads, the damage could cause a complete shutdown of the grid. Then everyone could be left without power.

The difference between a brownout vs. blackout is that a brownout is a period of reduced power, whereas a blackout is when you have no power at all. In both cases, it is about supply and demand.

How long do rolling blackouts last?

You might wonder: How long do rolling blackouts last? The answer depends on the severity of the supply shortfall and the persistence of peak demand.

Sometimes they last an hour or two; sometimes longer. Excessive demand can quickly spike, requiring companies to take fast action to protect the grid.

Who determines the rolling blackout schedule?

The process for initiating and managing rolling blackouts varies around the country. Typically, the regulatory body for electricity in your region orders rolling blackouts when their monitoring systems detect a problem. Your utility company is required by law to comply.

Most have plans in place that preserve power to sensitive sites and switch power on and off in specific sections of the grid until the order is canceled.

How rolling blackouts work

Rolling blackouts are necessary when electricity users demand more power than the grid can provide. Weather events, like extreme heat or cold, can cause a demand and supply imbalance. Other common causes of power outages include storms that knock out power at plants, power sources like wind and solar and substations or distribution lines. When these parts go down, the result can be supply shortages.

Whatever the cause, the solution of selectively and sequentially cutting power to specific areas in a rolling power outage can quickly bring demand back in balance with supply.

How can I prepare for a rolling blackout?

Because rolling power outages can happen quickly, you will want to be prepared while considering the needs of both your home and family. Some of the steps to take are different when you need to prepare for a winter power outage vs. one in the summer. While rolling blackouts are usually short, take the time now to also prepare for a long-term power outage.

  • Stock up on essentials. It might not be possible to get to the store during a rolling blackout. Retailers without electricity might not be able to operate and thus close their doors. Make sure to have food, water and essential medicines on hand.
  • Create an evacuation plan. If you have a place to go, you can save yourself discomfort and inconvenience by simply traveling to someplace that has power. Think about where you might go and plan to move your family, pets and valuables when the time comes.
  • Have a flashlight and batteries handy. Being able to see in the dark can keep your spirits up, but it is also a safety issue. Having a safe, non-flammable source of light is a necessity.
  • Buy a battery-operated radio. It is a good idea to have a way to access news and announcements. A radio that runs on batteries, particularly one that you can recharge with a hand crank or solar panel is preferable.
  • Protect appliances. When the power comes on, you face the risk of power surges that can damage appliances. You can protect them by unplugging them. Here are some other ways to protect your home from power surges.
  • Find out why your power is out and report it. You may have a localized power outage, confined to just your house or street. Check your own electric panel for tripped circuit breakers, then see if your neighbors are having the same problem. Take the time to report a power outage to your utility company.

How can I help prevent rolling blackouts?

While you can’t stop rolling blackouts single-handedly, you most definitely can play a part in preventing them. Reducing demand is the key, so it helps to look for ways to save energy at home and at work. Here are tips for contributing to the solution for preventing a rolling power outage in your area.

  • Perform energy-demanding tasks during off-peak hours. Spreading out demand is as important as reducing demand. If you run energy-hungry appliances when few others are demanding energy, you still get your work done but don’t contribute to spikes in demand that can trigger rolling blackouts.
  • Unplug appliances and electronics that aren’t in use. Because many modern appliances sip energy even in the “off” state, unplugging them reduces demand when not in use.
  • Take steps to improve your home’s energy efficiency. Conduct an energy audit of your whole home to see where you might be wasting power. Think about insulation upgrades to help save energy in winter and summer. Upgrade appliances to ENERGY STAR® models. Adopt new energy conservation habits.
  • Invest in smart home technology. Using technology to track and optimize your energy usage can dramatically reduce demand.

Now that we have answered the important questions of what a rolling blackout is, how rolling blackouts work, and how you can help prevent rolling power outages, you are ready to play your role in preventing them in the future.