Across Western Europe, power cuts temporarily plunged homes into darkness overnight. Millions of people were affected in France, Germany, Belgium, Austria, Spain and Italy.
When the power went out some people were in elevators, others were cooking and others were watching television. It was late Saturday, when millions were plunged into darkness across Western Europe.
Rail and underground trains were delayed, and thousands of worried citizens called the emergency services. No injuries were reported.
In France, about five million people were left without power, including many in the capital, Paris. Firefighters said about 15 French regions were affected, and many homes were still without electricity early Sunday. Homes in Austria, Belgium, Italy and Spain were also affected, though supplies were quickly restored.
Heavily populated areas of Germany, where the power outage originated, were also plunged into darkness.
Private German company Generator E.On A.G. said the problems began in the northwest of the country, where its network became overloaded, possibly because it shut down a high-voltage transmission line over a river to allow a ship to pass safely.
The company said it had shut down transmission lines in the past without causing problems, and that it was still trying to discover what happened this time.
In Italy, speaking to reporters in his hometown of Bologna, Prime Minister Romano Prodi said the incident suggested Europe needed to strengthen its coordination of power supplies.
He said there is a contradiction between having European power links and not having a European power authority. Prodi added that countries depend on each other, but are not able to help each other, and do not have a central authority.