2003 Italy blackout
The 2003 Italy blackout was a serious power outage that affected all of Italy—except the islands of Sardinia and Elba—for 12 hours and part of Switzerland near Geneva for 3 hours on 28 September 2003. It was the largest blackout in the series of blackouts in 2003, affecting a total of 56 million people. It was also the most serious blackout in Italy in 70 years.
Power went off at about 03:20 hrs. local time on 28 September 2003. Initial reports from Italy's electricity supplier, ENEL, stated that the power line which supplied electricity to Italy from Switzerland was damaged by storms, causing it to trip and also the two 400kV power lines between France and Italy to trip due to sudden increased demand from those two power lines. The cascading effect disrupted power supply to Italy from France and Switzerland. ENEL lost control of the grid in the next 4 seconds, with the lines tripped one by one amid the cascading effect. Swiss electricity company ATEL later concurred that a power line between Switzerland and Italy went out for a few hours.
The night of 27 September 2003 is the night of the annual overnight Nuit Blanche in Rome, the capital of Italy. Thus, many people were on the streets and all public transportation were still operating at the time of the blackout (at about 03:00 on 28 September 2003) despite the fact that it was very late at night. The blackout caused the carnival to end early. Several hundred people were trapped in underground trains. Coupled with heavy rain at the time, many people spent the night sleeping in train stations and on streets in Rome.
Throughout Italy, 110 trains were canceled, with 30,000 people stranded on trains. All flights in Italy were also cancelled. Police described the scene as chaos but there were no serious accidents.
The blackout, however, did not spread further to neighbouring countries, such as Austria, Slovenia and Croatia, which are connected to Italy. Only part of the Geneva Canton of Switzerland suffered a power outage for three hours.
Restoration of service 
After 3 hours, energy was restored in northern regions. Electricity was restored gradually in most places, and in most cities electricity were powered on again during the morning. Rolling blackouts continued to affect about 5% of the population on the next two days (29-30 September) as the electricity company ENEL continued its effort to restore supply.
Scientific research 
Researchers in physics and complex networks have 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.
- Sergey V. Buldyrev, Roni Parshani, Gerald Paul, H. Eugene Stanley & Shlomo Havlin. Catastrophic cascade of failures in interdependent networks. Nature 464, 1025-1028 (15 April 2010), http://www.nature.com/nature/journal/v464/n7291/abs/nature08932.html