A rolling blackout, also referred to as rota or rotational load shedding, rota disconnection, feeder rotation, or a rotating outage, is an intentionally engineered
electrical power
Electric power is the rate of transfer of electrical energy within a electric circuit, circuit. Its SI unit is the watt, the general unit of power (physics), power, defined as one joule per second. Standard prefixes apply to watts as with oth ...
shutdown in which
electricity delivery is stopped for non-overlapping periods of time over different parts of the distribution region. Rolling blackouts are a last-resort measure used by an
electric utility
An electric utility, or a power company, is a company in the electric power industry (often a public utility) that engages in electricity generation and distribution of electricity for sale generally in a regulated market. Electric utilities are ...
company to avoid a total
blackout of the power system.
Rolling blackouts are a measure of
demand response
Demand response is a change in the power consumption of an electric utility customer to better match the demand for power with the supply. Until the 21st century decrease in the cost of pumped storage and batteries, electric energy could not b ...
if the demand for electricity exceeds the power supply capability of the network. Rolling blackouts may be localised to a specific part of the electricity network, or they may be more widespread and affect entire countries and continents. Rolling blackouts generally result from two causes: insufficient
generation
A generation is all of the people born and living at about the same time, regarded collectively. It also is "the average period, generally considered to be about 20–30 years, during which children are born and grow up, become adults, and b ...
capacity or inadequate
transmission infrastructure to deliver power to where it is needed.
Rolling blackouts are also used as a response strategy to cope with reduced output beyond reserve capacity from
power station
A power station, also referred to as a power plant and sometimes generating station or generating plant, is an industrial facility for the electricity generation, generation of electric power. Power stations are generally connected to an electr ...
s taken offline unexpectedly.
In developing countries
Rolling blackouts are a common or even a normal daily event in many
developing countries
A developing country is a sovereign state with a less-developed Secondary sector of the economy, industrial base and a lower Human Development Index (HDI) relative to developed countries. However, this definition is not universally agreed upon. ...
,
where electricity generation capacity is underfunded or
infrastructure
Infrastructure is the set of facilities and systems that serve a country, city, or other area, and encompasses the services and facilities necessary for its economy, households and firms to function. Infrastructure is composed of public and pri ...
is poorly managed. In well managed under-capacity systems blackouts are planned and schedules are published in advance to allow people to work around them. In poorly managed systems they happen without warning, typically whenever the transmission frequency falls below the 'safe' limit.
These have wide-ranging impacts, and can effect the expectations of communities. For example, in Ghana
dumsor describes the widespread expectations for intermittent unexpected power outages due to rolling blackouts.
Iran
In 2021, Iran regularly conducted large blackouts nationwide.
In July 2024, the government started 4 hour per day blackouts affecting homes and industries despite 40 degrees Celsius heat waves, and the severity of power shortages exceeded worst case scenario predictions.
On 10 November 2024, the government began reimplementing blackouts nationally.
Philippines
Remote areas or off-grid areas are the most vulnerable to power supply issues. Areas placed with under yellow and red alerts are subject to rolling blackouts.
South Africa
Since 2007, South Africa has experienced multiple periods of rolling blackouts which are locally referred to as load shedding by the state-owned energy company
Eskom. This was initially caused by the country's demand for electricity outstripping supply, and as time progressed, later exacerbated by ageing power infrastructure, poor maintenance, and the slow completion of new power stations. It was recently revealed by Eskom's former spokesperson Sikhonathi Mantshantsh, that widespread tender corruption and the sabotage of power infrastructure by employees is one of the primary reasons for continuing load shedding. This has caused severe damage to the South African economy and has played a large part in limiting the country's economic growth.
Ukraine

In the late 1990s, Ukraine experienced frequent scheduled electricity blackouts throughout the country's power system due to miners' strikes, the destruction of the coal industry in 1991–1996, the hidden privatization of energy companies and
barters in the energy industry, which included even nuclear power.
During the
Russian invasion in 2022,
Russia
Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...
conducted multiple attacks on Ukraine's energy infrastructure. On 23 October 2022, rolling blackouts were introduced in
Kyiv
Kyiv, also Kiev, is the capital and most populous List of cities in Ukraine, city of Ukraine. Located in the north-central part of the country, it straddles both sides of the Dnieper, Dnieper River. As of 1 January 2022, its population was 2, ...
and its
oblast
An oblast ( or ) is a type of administrative division in Bulgaria and several post-Soviet states, including Belarus, Russia and Ukraine. Historically, it was used in the Russian Empire and the Soviet Union. The term ''oblast'' is often translated i ...
. Rolling blackouts were introduced in all Ukrainian regions on 25 October 2022.
In 2024, Ukraine faced another unprecedented
energy crisis
An energy crisis or energy shortage is any significant Bottleneck (production), bottleneck in the supply of energy resources to an economy. In literature, it often refers to one of the energy sources used at a certain time and place, in particu ...
due to Russia's destruction of energy infrastructure, re-introducing rolling blackouts. Approximately 70% of the country's heating infrastructure was either damaged or under occupation by May 2024.
Egypt
In the Summer of 2023, with the unprecedented heatwave that hit the country, the Egyptian government announced it would start a scheduled blackout across all major cities for 1 hour per day until the heatwave ended.
However, the blackouts remained well into the winter and were increased to 2 hours per day.
In the Summer of 2024, the temperatures rose even higher and the schedule changed to 3 hours per day with reports of unplanned cuts in
Alexandria
Alexandria ( ; ) is the List of cities and towns in Egypt#Largest cities, second largest city in Egypt and the List of coastal settlements of the Mediterranean Sea, largest city on the Mediterranean coast. It lies at the western edge of the Nile ...
,
Cairo
Cairo ( ; , ) is the Capital city, capital and largest city of Egypt and the Cairo Governorate, being home to more than 10 million people. It is also part of the List of urban agglomerations in Africa, largest urban agglomeration in Africa, L ...
and other cities where some places faced over 6 hours without electricity for 3 days.
In developed countries
Rolling blackouts in
developed countries
A developed country, or advanced country, is a sovereign state that has a high quality of life, developed economy, and advanced technological infrastructure relative to other less industrialized nations. Most commonly, the criteria for eval ...
sometimes occur due to economic forces at the expense of system reliability, or during natural disasters such as
heat wave
A heat wave or heatwave, sometimes described as extreme heat, is a period of abnormally hot weather generally considered to be at least ''five consecutive days''. A heat wave is usually measured relative to the usual climate in the area and ...
s.
Japan
After the
2011 Tōhoku earthquake and tsunami
On 11 March 2011, at 14:46:24 Japan Standard Time, JST (05:46:24 UTC), a 9.0–9.1 Submarine earthquake, undersea megathrust earthquake occurred in the Pacific Ocean, east of the Oshika Peninsula of the Tōhoku region. It lasted approx ...
, the
Tokyo Electric Power Company
is a Japanese electric utility holding company servicing Japan's Kantō region, Yamanashi Prefecture, and the eastern portion of Shizuoka Prefecture. This area includes Tokyo. Its headquarters are located in Uchisaiwaicho, Chiyoda, Tokyo, an ...
implemented rolling blackouts. Its service area was divided into five blocks and blackouts were implemented from 6:20 to 22:00. The schedule from 15 to 18 March 2011 was as follows:
USA
In
California
California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...
, rolling blackouts during
2000–01 California energy crisis occurred in June 2000, January, March and May 2001, and August 2020.
The
2021 Texas power crisis
In February 2021, the state of Texas suffered a major Energy crisis, power crisis, which came about during three severe winter storms sweeping across the United States on February 2021 North American ice storm, February 10–11, February 13� ...
involved rolling blackouts caused by the
February 13–17, 2021 North American winter storm
The February 13–17, 2021 North American winter storm was a crippling winter storm, winter and ice storm that had widespread impacts across the United States, Northern Mexico, and parts of Canada from February 13 to 17, 2021. The storm, unoff ...
and lack of
winterization. The
Late December 2022 North American winter storm resulted in rolling blackouts in parts of the eastern US.
Other
*
2003 Italy blackout
*
2016 South Australian blackout
Effects
Intermittent access to electricity causes major economic problems for businesses, which incur costs in the form of lost resources, reduced patronage, or curtailed production if electrical equipment—for example refrigeration, lighting, or machinery—abruptly stops working. Businesses in areas that are subject to regular blackouts may invest in
backup power generation to avoid these costs, but power backup is itself a cost because generators must be purchased and maintained and fuel must be regularly replenished.
Scheduling
When blackouts are scheduled in advance, they are easier to work around.
[
The speed at which blackouts roll may be adjusted so that no blackout lasts longer than a certain limit. For instance, in Italy, th]
PESSE
(''Piano di Emergenza per la Sicurezza del Sistema Electrico,'' Emergency plan for national grid safety) does not permit a controlled blackout longer than 90 minutes. In Canada, blackouts have been rolled so that no area had to spend more than one hour without power.
Causes
In some countries, generating capacity is chronically below demand. Assorted factors may prevent adequate investment in generation. Alternately, generating capacity may temporarily decrease below demand due to power station outages or loss of renewable capacity due to the wind dropping[ or the sun shining less. Natural disasters can also abruptly reduce supply by damaging power plants.][ A lack of fuel makes some types of power plant useless. Industrial accidents and poor maintenance can also take generation capacity offline. Conflict can disrupt fuel supply, as well as damage or destroy generating and delivery infrastructure.]
In electricity grids where power generators are paid a flexible market rate, power suppliers sometimes deliberately keep the generating capacity too low, or fake accidents that take capacity offline, to jack up prices.[
Demand spikes can also cause blackouts. Unusually hot][ or cold weather][ can cause demand spikes. Independent system operators may introduce rolling blackouts in anticipation of demand spikes, based on often arbitrary minimum thresholds of electricity reserves.]
In the case of South Africa
South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...
, failing and aged infrastructure, lack of maintenance and alleged corruption in the country's African National Congress
The African National Congress (ANC) is a political party in South Africa. It originated as a liberation movement known for its opposition to apartheid and has governed the country since 1994, when the 1994 South African general election, fir ...
-led government in the running of their primary electricity provider, Eskom, is the direct cause of rolling blackouts.
References
{{DEFAULTSORT:Rolling Blackout
Power outages