Electricity has been restored across Italy, as prosecutors launched an inquiry into what caused the worst blackout in the country's history.
Italy imports up to 17% of its electricity needs
Angry Italians have been demanding answers after more than 50 million people were left without power for several hours.
The European Commission says the blackout was caused by chronic energy congestion in parts of the European Union.
The power failure has highlighted Italy's heavily reliance on energy imports from neighbouring Switzerland and France.
The EU Energy Commissioner, Loyola de Palacio, on Monday called for the introduction of a single electricity network and a full opening up of national energy markets.
Industry Minister Antonio Marzano said he would make a statement to parliament on Tuesday, where he is expected to call for reforms to the electricity sector.
Sunday's power loss was the latest in a series of major blackouts to affect national power grids. In August, a vast section of the eastern United States and Canada lost power, hitting 50 million people.
August 14 - US and Canada
August 28 - London, UK
September 23 - Denmark, Sweden
September 28 - whole of Italy
The incident was followed two weeks later by one in the UK. Last week the Danish capital, Copenhagen, and southern Sweden were hit.
The blackout appears to have been triggered by a minor accident on a power line in neighbouring Switzerland, causing a domino effect in French lines which affected Italy. Parts of the Swiss city of Geneva were also blacked out.
Switzerland and France have blamed Italy for failing to take action that would have limited the scale of the problem, while Italy said France was at fault.
Andrea Bollino, chairman of the national grid company GRTN, has faced criticism for having reassured the Italian public after the US blackout that the problem could not happen there.
At least five people are reported to have died in accidents during the blackout. An estimated 30,000 were trapped on trains.
Only the island of Sardinia escaped the blackout, as it has its own electricity supply.
Environmental opposition to building new power plants means Italy has become more and more dependent on power imports.
A spokesman for Enel, the Italian utility company, said the country imported up to 17% of its power, compared with a Europe-wide average of 2%.
He said poor organisation in the Italian grid made the problem worse.