What is a Blackout?

G. Melanson

Also known as a power outage or power failure, a blackout is a loss of electricity within a given area. A blackout can be caused by a short circuit, overloaded electricity mains, or damage caused to power lines by inclement weather, falling trees, and other environmental factors. The term blackout is typically reserved for severe power outages which blanket a large residential area, or “grid,” and last anywhere from an hour to a few weeks.

It's a good idea to keep a manual can opener on hand in case of an extended blackout.
It's a good idea to keep a manual can opener on hand in case of an extended blackout.

Power failures that last only momentarily before electricity is restored are referred to as dropouts, and typically caused by a power line fault. Power failures that cause lights to dim rather than go out are the result of a decrease in voltage, and referred to as brownouts. Brownouts can cause devices such as air conditioners and CRT televisions to struggle in an attempt to draw more current, potentially resulting in damage from overheating.

A blackout may be cause by a downed power line.
A blackout may be cause by a downed power line.

Backup systems for critical electrical devices that ensure public safety are implemented during blackouts. Equipment for hospitals and air traffic control systems use generators to automatically continue the power supply when electricity is lost. Although generators only produce power for a limited amount of time, they allow for critical workers to finish what they were working on at the time of the outage without interruption. There are also backup systems available to individuals for electrically-powered devices in their homes, which can be damaged by the sudden surges of electricity that can occur during blackouts. Computer systems, which are particularly vulnerable to hardware damage and data loss, can be protected by an uninterruptible power supply (UPS), such as a backup battery.

Dropouts are typically when single electrical lines have gone down.
Dropouts are typically when single electrical lines have gone down.

The restoration of power following an electrical blackout that has spanned an entire power grid can be challenging. Much like a car with a dead battery that requires a “boost” from another car, power stations require help from another station within the same power grid to re-start the system. If all other stations within the grid are without power, a blackstart must be initiated, which involves an intricate process of coordination between transmission utilities and power stations.

In 2007, President George W. Bush signed a policy with the Energy Independence and Security Act for the United States to upgrade its power grids to a smart grid, which can minimize the risk of blackouts as well as reduce CO2 emissions and energy consumption. On a national scale, power outages cost Americans in excess of $100 billion US Dollars (USD), according to the Electric Power Research Institute (EPRI).

Many people use generators as a guard against blackouts.
Many people use generators as a guard against blackouts.

You might also Like

Readers Also Love

Discussion Comments


I grew up in a small town and remember one winter when the whole town had a blackout for three days. We had a gas stove in our kitchen, and we would put a blanket up across the doorway into the kitchen so all the heat would stay in one room.

This is the only way we could get any heat to stay somewhat warm. When you are a kid, this is a little exciting for about 1 hour, then you realize how inconvenient it is.

The whole family would crowd in that one small room. We would play games to try and pass the time, but even that got old after awhile. We always had enough food to get by though.

You could almost hear the cheering across the whole town when they got the electricity turned back on.


It seems like every winter we have a blackout for a few hours to a few days. We have had several ice storms in the last few years, and that causes our whole neighborhood to lose electricity.

While hospitals and many major companies have generators to ensure that things continue to run smoothly, it still creates havoc.

You really don't realize how much you depend on electricity until you have to go without it for a few hours or days. This is especially hard when it is below zero outside and there is no way to get warm.

Sometimes you have to rely on friends and family members who live close by that still have their electricity.


@FernValley- My sisters were stuck in a blackout in New York City a few years ago. It was terrible because a lot of people were stranded because they had checked out of their hotels and then had nowhere to go because everything was at a standstill.

Luckily my oldest sister was able to have my other sister stay with her and she took a cab to her home, but a lot of people were not that lucky.

When the subways stop working in New York City it causes horrific transit problems all over the city. Even a blackout of a few hours is enough to do major damage.


@FernValley- I was still in school then, and some stores in town started selling "I survived the blackout" t shirts, even though it had not lasted that long at all in our area. I remember thinking that it seemed like every world event was turning into a joke, and that was even before most social media. I can't imagine how people would react now.


I remember several years ago now when a large percentage of the US power grids blacked out for several hours, people panicked. Even though that event turned out to not be so bad, I guess it showed how vulnerable people are these days when we cannot get access to electricity and everything it supports in our lives.

Post your comments
Forgot password?