1st Feb 2022
How long do power outages last?
You can precisely predict anything except the future. In short … you can’t predict anything precisely, power outage durations included. Not even the people working to fix it can predict exactly how long it will be. But, if you gather a few facts, you can predict it roughly.
The author was mopping up the floor in several rooms. An incredibly rare summer storm called a derecho had blown through town. Three distinct lines of thunderstorms had coalesced into one monster that travelled several hundred miles, wreaking havoc indiscriminately. (People who’d experienced hurricanes in South Carolina said they’d never seen anything like it.)
He’d left certain windows open. From experience, he knew the roof overhang sheltered them sufficiently.
But that meant nothing to this storm. Wind and water cascaded through every window he’d left cracked open. The lights flickered several times before finally staying out.
So, as the mopping up began, he was thinking … Was it possible this powercut might not be short?
All the more ironic when you consider his brother is one of the local severe weather warning forecasters.
How to predict the duration of your current outage
The first thing to do when your lights go out is: Gather facts.
He checked the whole house. Yup, it’s not just a single circuit.
Then he looked across the street. The sky had gotten so dark, there was no chance of all the neighbors leaving all the lights off. And they were all dark, so this was at least neighborhood-wide.
In general, the more severe and widespread the event causing the outage, the longer it takes to repair it. And there was no doubting what had caused this outage.
An outage in the middle of a bright sunny day will probably be Short, i.e. less than 2 hours.
Short outages are caused by single component failures or scheduled maintenance. Electrical equipment lasts a long time, but not infinitely; they can, and do, fail. Rodents and birds will get inside equipment and trip circuits. Local inclement weather, e.g. lightning strikes, will also cause circuits to trip, but even these can be corrected quickly.
The severity of this storm suggested the outage might be more than a simple component failure.
Moderate outages are typically 2 to 12 hours long. They typically result from more significant failures, e.g. of an entire system, substation or generation plant. Identifying the failure is usually not too time-consuming. Restarting an entire plant or system, however, is not quick; startup procedures and checks have to be followed.
The author suspected something of this nature.
Long outages last beyond 12 hours, sometimes days. They usually result from multiplebig failures in the electrical grid. They take far longer to diagnose, let alone correct.
It took little of the author’s brain power to deduce that the storm had probably caused multiple failures. His next course of action was to get some idea of how many.
The wifi was knocked out. Could he access the internet through cell phone data?
Turns out, he could. (Otherwise, his next port of call would have been to local radio stations via cell phone or battery radio.)
The first site he checked was the local electrical utility, which he knew had an online page where blackouts could be reported by customers. It also had a map indicating areas of the city currently under blackout.
The page was accessible. Where the map would normally be, however, was displayed a simple sentence to the effect that it was overwhelmed with too many incoming reports. Not a good sign.
Next, a check of the local news sites. Turns out, the storm had knocked down trees, power lines and major transmission towers, across the city and surrounding region.
Utility staff were already scrambling, but still didn’t know the full extent of the failures. Citizens were being advised to protect their food and water sources, and to check on vulnerable people in their areas.
That was all the author needed to conclude: The power would be out for days. There would be no quick return to normality.
So how long will your power be out?
Two big factors affect the answer to that:
Electrical power grids are not all created equal.
They vary widely in design from state to state, country to country. They vary because the topography, and the available generation and human resources vary. They vary because people, population densities, and politics vary.
And this means the electrical grid reliability and integrity is just as variable.
Some states and countries have large, highly-skilled populations that make designing very robust grids and generation plants possible. Others do not, and they are more blackout-prone.
This makes for interesting statistics when it comes to blackouts.
For example, blackouts in Montana are typically 80% longer than those in the state of Washington.
But total blackout minutes? Higher in Washington. (In short, Washington has a lot more blackouts, but they’re shorter.)
Two useful sites for checking the performance history of your state are Statista and Cummins.
2. The event that causes the blackout
And these include the causes already mentioned (weather, animals, equipment decay), but also scheduled maintenance, tree damage, and people. (Utility and generation plant staff do make mistakes. Remember Three mile Island?)
Actions to take in an outage
These will depend on your fact-gathering, and the prediction you reach about the likely duration.
A mid-sunny-summer-day blackout will probably be short, so the action is more about what you don’t do:
- Don’t open the fridge or freezer doors (any more than you have to).
- Report the failure to your utility, and inquire about the suspected cause.
For suspected moderate and long outages, conversely, especially those in wintertime, you will need to protect your stored food, and deploy any backup power devices you have at the ready.
The end of the author’s storm
The derecho of May 2022 caused significant damage to the electrical grid in the author’s city.
The author and his family were among the fortunate. They knew of a facility with functioning empty freezers that had not lost power. They moved their frozen food there. And incredibly, power to their home was restored after just 22 hours.
But many of their neighbors were not so fortunate. (One neighbor had a young boy with autism who couldn’t stop opening the fridge door through the blackout - they had to discard all their frozen and refrigerated food.) Some homes were still unpowered a week later.
The local utilities conducted 2 years’ worth of maintenance work in a single week.