Power Insights Blog

What causes power outages?

What causes power outages?

1st Mar 2022

Electrical power grids are all about enabling human beings to live comfortable, fairly predictable lives on a chaotic planet.

The factors influencing the creation of an electrical power grid are the same factors that contribute to their failure. And they all amount to an attempt to control the uncontrollable.

Think about it. If you didn’t have electrical power, your life would be far more hellish than it is now.

You’d be constantly lighting (and extinguishing, and buying) candles and oil lanterns. Forget your computer and cell phone. Forget the radio and TV. Forget your electronically-controlled home heating (and air conditioning) systems. (You’d probably be lighting fires and chopping a lot of firewood.)

Forget most of the comforts and conveniences that you have come to take for granted.

They all depend on an electrical grid that has been highly engineered (by clever but imperfect human beings) with integrity and reliability in mind.

Problem is … nothing … read: Nothing … is failure-free. It’s possible to put a saddle on Mother Nature … but she’s never going to be a tame horse.


So electrical power outages are just the price we pay for learning from Mother Nature secrets about how she can be harnessed … but never tamed.

Here’s why power outages happen:

Loss of power generation/supply

Your utility is responsible for distributing power to homes.

Not for creating the power. That the nuclear (or coal, or oil, solar, wind, etc) power plant’s job. And sometimes they go down, for reasons only they know about.

Can’t be helped. You can’t give what you haven’t received.

Weather/Lightning damage

Electrical grids are designed with the weather in mind.

But to do that, engineers have to ask Mother Nature, What are you going to do that we might have to withstand? Where’s the next lighting bolt going to strike? How strong is the wind going to be? How many inches will it rain?

Mother Nature is not in the habit of answering that question.

So the engineers have to make assumptions. And guess what? They get it wrong sometimes.

Add to that: Designing a system that withstands what Mother Nature throws at it is really expensive. You’ll sometimes hear engineers or weather forecasters talk about a hundred-year storm, i.e. a storm expected (based on historical data) to only occur once per hundred years.

“That power outage we just got hit with was due to a hundred-year storm.”

“Well, why don’t they design it for the thousand-year storm, or the million-year storm?”

Because the cost of building the grid becomes so incredibly high, no authority will approve it. (And you won’t want to see the figure on your next utility bill.)

Add to that: Sometimes it’s not the weather here on planet earth that causes your power cut … but the weather on the surface of the sun.

Solar flares cause bursts of electromotive force (EMF) that can knock out grids in large areas. (Happened province-wide in Quebec on March 10, 1989.) Solar flares are not common, but neither are they uncommon. Power grids are designed with such EMF bursts in mind.

But as with wind and rain, they have to guess (and select) the magnitude of the EMF that can be withstood affordably.

Vehicle/Animal/Tree damage

People sometimes do stupid things.

They drive their cars or trucks into objects they shouldn’t.

Animals crawl into confined spaces (containing high-voltage equipment) because the heat keeps them warm in wintertime.

Trees rot and fall (even when the wind isn’t blowing particularly strongly). And power lines don’t react well to trees falling across them. This is why utilities will often take down seemingly healthy trees near power lines - they are just preventing a future outage.

Fortunately, outages caused by vehicle/animal/tree damage usually only affect neighborhoods, not entire towns or cities (or worse).

Component failure

Electrical components are, in general, robust. Their lives are longer than mechanical components, because they have fewer (if any) moving parts.

But even they suffer from corrosion, which causes their electrical properties (resistance, capacitance, inductance) to degrade. Just one sufficiently-degraded component can trigger an outage.

Fortunately, such outages are generally very local and short.

Human factors, and Scheduled maintenance

Because components … and by implication, grids … aren’t infinite-life, they have to be maintained, checked, tested, and monitored.

And this introduces the human factor alluded to earlier. Human beings are not perfect. They make mistakes. They get sick and tired when on duty (making mistakes more likely).

Maintenance must be calculated, programmed and scheduled. And the maintenance programme must be designed and maintained itself. It has to be staffed, directed, and monitored.

(If you ever peruse career or job search sites, you’ll sometimes see the acronym RAMS. This stands for Reliability, Availability, Maintainability, Safety. RAMS experts are the people calculating the safety and integrity of a highly-engineered system, and their maintenance programs.)

Maintenance engineering is an entire engineering sub-discipline. A large fraction of every utility’s staff are trained, skilled maintenance engineers. That’s all they do for their entire careers. They have to be paid enough to dissuade them from doing any other career.

This isn’t cheap or easy. Which introduces …

Political factors

Because installing and maintaining an electrical grid amounts to very Big Bucks.

Bucks that generally only governments control and authorize. Hence the design and performance of electrical grids get subjected to the whims of politicians and bureaucrats as much as anything else.

Meaning, they will sometimes attempt to influence technical decisions for their own personal political gain.

And the politics are not confined to the halls of the government paying for the grid. It can come within the utility. Personalities and temperaments can clash. Every human being in a position of leadership or authority brings a bias to the job. That bias may not place much importance on maintenance or design for reliability.

Political factors, on their own, do not cause power outages. But they can be complicating factors.

They only come to light when significant outages occur for other reasons (e.g. solar flares). The resulting investigation can reveal design flaws that stem in part from political meddling.

The Unknown

This might sound like a delegation of responsibility, but it’s not.

Sometimes power outages occur for no reason that the utility can pinpoint.

They can guess and speculate. But they lack any evidence suggesting a particular cause. And it is literally documented as Cause Unknown.

This never sits well with the utility, as it doesn’t with you or me. It means some event caused a failure, and because they don’t understand it, they are powerless to prevent a recurrence.