The 2003 Italy blackout was a serious

power outage A power outage, also called a blackout, a power failure, a power blackout, a power loss, a power cut, or a power out is the complete loss of the electrical power network supply to an end user. There are many causes of power failures in an el ...

that affected all of the Italian Peninsula for 12 hours and part of

Switzerland Switzerland, officially the Swiss Confederation, is a landlocked country located in west-central Europe. It is bordered by Italy to the south, France to the west, Germany to the north, and Austria and Liechtenstein to the east. Switzerland ...

near

Geneva Geneva ( , ; ) ; ; . is the List of cities in Switzerland, second-most populous city in Switzerland and the most populous in French-speaking Romandy. Situated in the southwest of the country, where the Rhône exits Lake Geneva, it is the ca ...

for 3 hours on 28 September 2003. It was the largest blackout in the series of blackouts in 2003, involving about 56 million people.

Causes

The

sequence of events Time is the continuous progression of existence that occurs in an apparently irreversible succession from the past, through the present, and into the future. It is a component quantity of various measurements used to sequence events, to compa ...

leading to the outage began at approximately 3:00 a.m. (

local time Local time is the time observed in a specific locality. There is no canonical definition. Originally it was mean solar time, but since the introduction of time zones it is generally the time as determined by the time zone in effect, with daylight s ...

) on 28 September 2003, when the 400 kV Lukmanier powerline on the Mettlen-Lavorgo powerline arced to a nearby

tree In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, e.g., including only woody plants with secondary growth, only ...

and automatically disabled itself. The line had carried

hydroelectric Hydroelectricity, or hydroelectric power, is Electricity generation, electricity generated from hydropower (water power). Hydropower supplies 15% of the world's electricity, almost 4,210 TWh in 2023, which is more than all other Renewable energ ...

power from

Italy Italy, officially the Italian Republic, is a country in Southern Europe, Southern and Western Europe, Western Europe. It consists of Italian Peninsula, a peninsula that extends into the Mediterranean Sea, with the Alps on its northern land b ...

, and this current now flowed on

parallel Parallel may refer to: Mathematics * Parallel (geometry), two lines in the Euclidean plane which never intersect * Parallel (operator), mathematical operation named after the composition of electrical resistance in parallel circuits Science a ...

lines through

France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

, overloading them. Those circuits could only stably carry the current for approximately 15 min, but the Swiss control room operator was not aware of the urgency. Instead, the operator attempted to re-energize the Lukmanier line, which was impossible because a large

phase difference In physics and mathematics, the phase (symbol φ or ϕ) of a wave or other periodic function F of some real variable t (such as time) is an angle-like quantity representing the fraction of the cycle covered up to t. It is expressed in such a s ...

had developed across the line. After repeated failures to re-energize, the operator asked the Italian transmission operator GRTN to reduce its import of power—by now, 10 min into the

grace period A grace period is a period immediately after the deadline for an obligation during which a late fee, or other action that would have been taken as a result of failing to meet the deadline, is waived provided that the obligation is satisfied duri ...

. GRTN succeeded in reducing power demand 10 min later, but by then the parallel lines had overheated. At 3:20, they, too, flashed to

ground Ground may refer to: Geology * Land, the solid terrestrial surface of the Earth * Soil, a mixture of clay, sand and organic matter present on the surface of the Earth Electricity * Ground (electricity), the reference point in an electrical circ ...

, disconnecting Italy from its suppliers to the North. Without imported power from the north, GRTN lost control of the grid in the next 4 seconds. Frequency dropped to 49 Hz, but this also removed ca. 7.5 GW of distributed power plants from the grid and the under-voltage load shedding (UVLS) could not compensate (cf. figure "Frequency behavior in Italy in the transitory period", UCTE report, April 2004, p. 115). Frequency continued to drop until the under-frequency threshold of 47.5 Hz was hit, and all generators were tripped according to the under-frequency protection settings.

Effects

The night of 27 September 2003 was the first

Nuit Blanche Nuit Blanche () (White Night) is an annual all-night or night-time arts festival of a city. A Nuit Blanche typically has museums, private and public art galleries, and other cultural institutions open and free of charge, with the centre of the ...

Rome Rome (Italian language, Italian and , ) is the capital city and most populated (municipality) of Italy. It is also the administrative centre of the Lazio Regions of Italy, region and of the Metropolitan City of Rome. A special named with 2, ...

. Thus, many people were on the streets and all public transportation were still operating at the time of the blackout (at about 3:00 on 28 September 2003) despite the fact that it was very late at night. Although the festival had already slowed due to heavy

rain Rain is a form of precipitation where water drop (liquid), droplets that have condensation, condensed from Water vapor#In Earth's atmosphere, atmospheric water vapor fall under gravity. Rain is a major component of the water cycle and is res ...

s, the blackout marked its definitive end. Several hundred people were trapped in

metro Metro may refer to: Geography * Metro City (Indonesia), a city in Indonesia * A metropolitan area, the populated region including and surrounding an urban center Public transport * Rapid transit, a passenger railway in an urban area with high ...

trains. Throughout Italy, 110 trains were cancelled, stranding 30,000 people, although flights proceeded as normal. Many people spent the night sleeping in train stations and on streets in Rome. Police described the scene as chaos but there were no serious accidents. The blackout did not spread further to neighboring countries, such as

Austria Austria, formally the Republic of Austria, is a landlocked country in Central Europe, lying in the Eastern Alps. It is a federation of nine Federal states of Austria, states, of which the capital Vienna is the List of largest cities in Aust ...

Slovenia Slovenia, officially the Republic of Slovenia, is a country in Central Europe. It borders Italy to the west, Austria to the north, Hungary to the northeast, Croatia to the south and southeast, and a short (46.6 km) coastline within the Adriati ...

and

Croatia Croatia, officially the Republic of Croatia, is a country in Central Europe, Central and Southeast Europe, on the coast of the Adriatic Sea. It borders Slovenia to the northwest, Hungary to the northeast, Serbia to the east, Bosnia and Herze ...

, which are connected to Italy. Only part of the

Geneva Canton The Canton of Geneva, officially the Republic and Canton of Geneva, is one of the 26 cantons of the Swiss Confederation. It is composed of forty-five municipalities, and the seat of the government and parliament is in the city of Geneva. Gen ...

of Switzerland suffered a power outage for three hours.

Restoration of service

After three hours, energy was restored in northern regions. Electricity was restored gradually in most places, and in most cities electricity was powered on again during the morning.

Rolling blackout 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 shutdown in which electricity delivery is stopped for non-over ...

s continued to affect about 5% of the population on the next two days (29–30 September) as the electricity company GRTN continued its effort to restore supply.

Investigations

The final report of the investigation committee on the 28 September 2003 blackout in Italy was published in April 2004 by

UCTE The European Network of Transmission System Operators for Electricity (ENTSO-E) is an association representing 40 electricity transmission system operators (TSOs) from 36 countries across Europe, thus extending beyond EU borders. It manages the ...

. The blackout also proved a useful

case study A case study is an in-depth, detailed examination of a particular case (or cases) within a real-world context. For example, case studies in medicine may focus on an individual patient or ailment; case studies in business might cover a particular f ...

for researchers in

physics Physics is the scientific study of matter, its Elementary particle, fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge whi ...

and complex networks, who modelled the 2003 Italy blackout as a cascade of failures in interdependent networks. Several nodes in the network of power stations failed, causing a failure of the Internet communication network, which in turn caused a further breakdown of power stations. The goal of research was to understand how to build more robust networks.

References

External links