On 28 September a tree falling on to a power line in Switzerland plunged most of Italy into a major blackout. Electricity was quickly restored in the north of the country, but Rome was without electricity for 12 hours, and parts of the south of Italy were without power for over 24 hours.

It is thought that the falling tree broke a major power line carrying power from Switzerland to Italy, which caused overloading on lines from France to Italy, which were subsequently disconnected.

Etrans, coordinator of the Swiss transmission network, said that it alerted Italy about the downed line, and told them to increase their own production to compensate. It said that Italy was too slow to react, resulting in other lines from France, Switzerland, Austria and Slovenia becoming overloaded and eventually disconnected. However, the Italian industry minister Antonio Marzano said that the blackout was not Italy’s fault, but was caused by events outside Italy. He called for a vote on a bill to increase existing electrical generation capacity by 25%.

The Italian prime minister, Silvio Berlusconi, said that the Italian government was preparing to rush into law a special blackout decree to allow the swift construction of new power stations. The government decree will aim to eliminate bureaucratic delays and permit a rapid, huge building programme. It hopes that liberalisation of the transmission market will encourage foreign investment into the sector.

Public opinion on nuclear power in Italy appears to be changing, and among the options are utility Enel taking equity in French nuclear capacity, and restarting two Italian reactors closed down by government decision in 1987. These could be back online in 18 months ­ the 260MWe Trino Vercellese PWR had been operating for 22 years and the 860MWe Caorso BWR only six years.

Italy currently relies on imports for 17% of its power, mainly from France.

On 26 September, parts of Sweden, and Denmark’s capital, Copenhagen, were hit by a power cut, leaving 5 million people without electricity for four hours.

It is thought that the blackout was caused by the failure of a faulty transmission line connecting Denmark and Sweden. The power cut took place just after Oskarshamn 3 in Sweden was shut down due to a fault in the transmission line.

Mikael Engvall, a spokesman for the Swedish grid network operator Svenska Kraftnet, said that the closure of Oskarshamn triggered automatic shutdowns at the Ringhals 3 and 4 nuclear units because they could not transmit the electricity they were generating. The resulting power shortage lowered voltage on eastern Denmark’s grid, causing a sequential shutting down of Danish power plants. The problem was made worse by the fact that a cable linking Denmark to Germany was closed for repairs.

About a month earlier, the UK’s National Grid was comparing itself favourably to the US transmission system: the UK, it was pointed out, enjoyed higher levels of investment than the USA, and such a domino effect of catastrophe as endured by the USA was unlikely. Soon after, London was blacked out, followed by Birmingham a week later. Although the London blackout lasted less than an hour, as in New York, the knock-on effect on commuters was marked, with widespread travel disruption.