Wikipedia Deep Dive

Rolling blackout

11 min read

Imagine you're stuck in an elevator when the power cuts out. Not because of an accident or a storm, but because someone at a power company decided it was your neighborhood's turn to go dark. This is the reality of rolling blackouts—and for millions of people around the world, it's not a nightmare scenario but an ordinary Tuesday.

The Controlled Catastrophe

A rolling blackout is, paradoxically, a success story. It means the power grid didn't collapse entirely.

Here's the basic problem: electricity grids must balance supply and demand in real-time, down to the fraction of a second. Unlike water in a reservoir or grain in a silo, electricity cannot be easily stored. At any given moment, power plants must generate almost exactly as much electricity as consumers are using. If demand outstrips supply, the entire system can cascade into failure—a total blackout that might take days to restore.

Rolling blackouts are the emergency brake. Power companies deliberately cut electricity to some neighborhoods for a set period—typically one to four hours—then restore power and cut it to a different area. The "rolling" part means the pain gets distributed. Your block goes dark from 2 to 4 PM. The next neighborhood over takes their turn from 4 to 6 PM. Nobody gets power all day, but nobody loses it all day either.

It's triage for the electrical grid.

Two Roads to Darkness

Rolling blackouts generally stem from one of two fundamental problems, and understanding which one you're dealing with matters enormously.

The first is insufficient generation capacity. There simply aren't enough power plants producing enough electricity to meet everyone's needs. This is the chronic condition affecting many developing nations, where economic growth has outpaced infrastructure investment. Building power plants is expensive, takes years, and requires political stability and access to capital that not every country enjoys.

The second is inadequate transmission infrastructure. Here, the electricity exists—it's being generated somewhere—but the wires, substations, and transformers needed to deliver it to consumers are missing, damaged, or overloaded. You might have a hydroelectric dam producing gigawatts of power in the mountains, but if the transmission lines to the city are too thin or too few, that power has nowhere to go.

In practice, many rolling blackout situations involve both problems tangled together.

The Developing World's Daily Companion

In wealthy countries, a power outage is an event. People post about it on social media. It makes the news. Frozen food spoils and becomes a minor tragedy. But in much of the world, unreliable electricity is simply the baseline condition of life.

Ghana has a word for it: dumsor. The term, which roughly translates to "off-on," describes the widespread expectation that power will come and go unpredictably throughout the day. It's not just a description of infrastructure—it's become part of the cultural vocabulary, a shared understanding that electrical reliability is a luxury rather than a given.

Well-managed systems publish blackout schedules in advance. Citizens can plan around them: charge your phone before 3 PM, cook dinner before your neighborhood goes dark, schedule business meetings for hours when you know you'll have power. Poorly managed systems offer no such courtesy. The lights simply go out when the grid frequency drops below safe operating limits, and you learn to live with surprise.

South Africa: A Case Study in Decline

South Africa's experience with rolling blackouts—known locally as "load shedding"—offers a cautionary tale about how a relatively advanced infrastructure can decay into chronic crisis.

The country's troubles began in 2007, when electricity demand finally exceeded what the state-owned utility Eskom could supply. But what started as a temporary mismatch has evolved into something far more intractable. Aging power plants that should have been maintained or replaced limped along. New power station construction fell behind schedule—in some cases, by decades. Corruption allegations mounted, with a former Eskom spokesperson recently claiming that tender corruption and deliberate sabotage by employees rank among the primary causes of ongoing shortages.

The economic damage has been staggering. Businesses cannot operate reliably. Manufacturers cannot maintain production schedules. The cold chain for food and medicine breaks down. Foreign investors, looking at a country where the lights might go out for several hours on any given day, take their money elsewhere.

Load shedding has become a fixture of South African life, with different "stages" indicating how severe the cuts will be on any given day. Stage 1 might mean occasional interruptions. Stage 8 means the grid is in crisis, with consumers spending more time without power than with it.

War's Invisible Front

When Russia invaded Ukraine in 2022, missiles and drones didn't just target military installations. They systematically attacked the country's power infrastructure—generating stations, substations, transmission lines. By targeting electricity, an invading force can inflict suffering on an entire civilian population without directly firing on homes and hospitals.

By late October 2022, rolling blackouts had become nationwide. Kyiv and surrounding areas experienced scheduled outages as engineers struggled to keep the damaged grid from collapsing entirely. By May 2024, approximately 70% of Ukraine's heating infrastructure was either damaged or under Russian occupation.

This represents something darker than mere infrastructure problems. It's the deliberate weaponization of electricity—or rather, its absence. An elevator stuck between floors during a scheduled blackout isn't just inconvenient in a war zone. It's a reminder that survival itself depends on systems that enemies can destroy from hundreds of miles away.

Ukraine had experienced rolling blackouts before, during the chaotic 1990s. Back then, the causes were economic: miners' strikes, a collapsing coal industry, murky privatization deals in the energy sector. The infrastructure existed but couldn't function in the post-Soviet economic chaos. What's happening now is different—the infrastructure is being systematically destroyed.

Climate as Amplifier

Heat waves are becoming the great revealer of electrical grid weaknesses.

When temperatures soar, air conditioners switch on by the millions. Each one draws power. The grid strains under loads it wasn't designed to handle, loads that occur at precisely the moment when power lines themselves become less efficient. (Hot wires carry electricity less efficiently than cool ones—a cruel irony of physics.) Power plants that rely on cooling water may find rivers running too low or too warm. Natural gas plants may struggle to import fuel if pipelines are at capacity. Solar panels actually become less efficient as they heat up.

Egypt discovered this in 2023 when unprecedented heat forced the government to implement scheduled blackouts across major cities. What started as a one-hour daily interruption expanded to two hours, then three. In some areas of Cairo and Alexandria, residents reported six-hour stretches without power for days at a time—during weather that made air conditioning feel less like a comfort and more like a survival necessity.

Iran has faced similar challenges. In July 2024, with temperatures exceeding 40 degrees Celsius (104 degrees Fahrenheit), the government implemented four-hour daily blackouts affecting homes and industries alike. The severity of shortages exceeded even worst-case predictions. By November, another round of blackouts was underway.

When Rich Countries Go Dark

Wealthy nations are not immune. They simply experience rolling blackouts less frequently—and find them more shocking when they occur.

California's rolling blackouts during 2000 and 2001 became a national scandal. The immediate cause was a perfect storm of factors: energy market deregulation that created perverse incentives, drought conditions that reduced hydroelectric output, and aging power plants that struggled to meet surging demand. Evidence emerged that some power generators had deliberately kept capacity offline to drive up prices—a reminder that market manipulation can manufacture scarcity as effectively as physical infrastructure failures.

The state experienced rolling blackouts again in August 2020, during a brutal heat wave that stressed the grid beyond its limits.

Texas learned its own harsh lessons in February 2021, when a severe winter storm exposed the fragility of a grid that had never been properly winterized. Natural gas wells froze. Wind turbines without cold-weather packages locked up. Power plants that should have been generating electricity sat idle. What followed wasn't just rolling blackouts but, in some areas, prolonged outages that left families without heat in subfreezing temperatures. Hundreds died.

Japan, too, knows this experience. After the 2011 Tōhoku earthquake and tsunami destroyed the Fukushima Daiichi nuclear power plant, the Tokyo Electric Power Company divided its service area into five blocks and implemented rolling blackouts from early morning until late night. For a country that prided itself on technological excellence and reliable infrastructure, the scheduled outages represented a profound shock.

The Economics of Darkness

Every hour without power carries a price tag.

Refrigerated goods spoil. Manufacturing lines stop. Retail stores lose customers who can't shop in the dark. Service businesses send workers home when computers won't boot. Each interruption ripples through the economy, creating losses that may never be fully tallied.

Businesses facing regular blackouts often invest in backup generators—diesel or natural gas units that can kick in when the grid fails. But generators are expensive to purchase, expensive to fuel, and expensive to maintain. They represent a private solution to a public infrastructure failure, and not every business can afford them. The bakery on the corner can't necessarily justify the same backup power investment as the data center downtown.

Predictability helps, at least somewhat. When blackouts are scheduled and published in advance, businesses can adjust. A restaurant might shift its dinner service to coincide with hours when power is guaranteed. A factory might schedule its most electricity-intensive operations for the morning if afternoons are known blackout periods. This adaptation is possible—it's also inefficient, representing economic activity constrained by infrastructure limitations.

Some jurisdictions have formalized how blackouts should roll. Italy's emergency plan prohibits any controlled blackout from lasting more than 90 minutes. Canadian utilities have rolled outages so that no area loses power for more than an hour at a stretch. These rules recognize that shorter interruptions, while annoying, are far less damaging than extended ones.

The Supply Side

Why isn't there enough electricity? The answers vary, but some patterns recur.

Underinvestment is perhaps the most common culprit. Power plants take years to plan and build. They require enormous capital expenditure upfront for benefits that accrue over decades. Political instability, corruption, and simple short-term thinking can all prevent the necessary investments from being made.

Aging infrastructure compounds the problem. Power plants have lifespans. A coal plant built in the 1970s may still be operating fifty years later, but it's operating at reduced capacity, requiring constant maintenance, and prone to unexpected breakdowns. Every plant that goes offline for repairs represents megawatts the grid can't count on.

Fuel supply matters too. A natural gas plant is useless without natural gas. A coal plant needs coal. Disruptions to fuel supply—whether from strikes, international conflicts, or simple logistics failures—can idle otherwise functional generating capacity.

Renewable energy introduces new variables. Wind power depends on the wind blowing. Solar power depends on the sun shining. When weather doesn't cooperate, backup sources must fill the gap. This isn't an argument against renewable energy—it's a recognition that grids dependent on variable sources need robust backup capacity and sophisticated management.

And then there's deliberate manipulation. In deregulated electricity markets, power generators are sometimes paid flexible rates based on supply and demand. This creates an incentive to restrict supply artificially. Keep a power plant offline for "maintenance" during a heat wave, and the price of electricity spikes. Investigations into the California energy crisis of 2000-2001 revealed exactly this kind of market manipulation.

The Demand Side

Supply is only half the equation. Demand spikes can overwhelm even well-maintained grids.

Extreme weather is the most common trigger. Heat waves drive air conditioning loads through the roof. Cold snaps push electric heating to maximum. Both scenarios can produce demand that exceeds even generous reserve margins.

Independent system operators—the entities that manage electrical grids across regions—sometimes introduce rolling blackouts preemptively, based on forecasts suggesting demand will exceed supply. The thresholds for these decisions can seem arbitrary from the outside. A grid operator might call for blackouts when reserves fall below 5%, even if the lights could theoretically stay on at 4%. The caution reflects hard lessons: letting the grid get too close to its limits risks cascade failures far more damaging than controlled, scheduled interruptions.

Living With Uncertainty

For billions of people, unreliable electricity isn't a temporary crisis. It's simply life.

They charge their phones when they can, not when convenient. They cook around blackout schedules. They invest in candles, flashlights, backup batteries, and generators if they can afford them. They accept that some businesses simply can't operate reliably, and structure their economic lives around that constraint.

The question of whether rolling blackouts represent failure or success depends entirely on the alternative. Compared to reliable 24/7 electricity, they're obviously inferior. Compared to total grid collapse, they're a triumph of engineering and management—a controlled sacrifice of some to preserve the whole.

The elevator stuck between floors during a scheduled blackout represents both: a failure of infrastructure and, simultaneously, a system working exactly as designed in crisis. The power will come back on. It just won't be right now.

Whether that compromise is acceptable depends largely on whether you're the one stuck in the elevator—and whether you had any warning before the lights went out.