Power is returning across Spain and Portugal after a massive outage yesterday.
The incident, which is under investigation, resulted in transport chaos with hospitals cancelling some services. Schools are expected to be shut today.
Spain declared a state of emergency.
Madrid has meanwhile urged caution over speculating about the causes of the outage.
Reports on Monday suggested that due to extreme temperature variations in the interior or Spain, there were anomalous oscillations in the very high voltage lines (400 KV), a phenomenon known as ‘induced atmospheric vibration’.
These oscillations caused synchronisation failures between the electrical systems, leading to successive disturbances across the interconnected European network, according to some reports.
However, Madrid said the investigation is ongoing although it has ruled out a cyberattack.
The Mayor of Madrid yesterday warned people to stay off the roads and think before contacting the emergency services.
There are also reports that mobile phone and internet connections were down.
In Portugal, traffic lights were down, and the metro in Lisbon and Porto was closed.
Train and plane services were also not running in parts of both countries.
Andorra and parts of France were also affected.
Spanish grid operator RedElectrica said: “The restoration of electricity supply is progressing in various parts of the country.
“Electricity is now available in parts of Catalonia, Aragon, the Basque Country, Galicia, La Rioja, Asturias, Navarre, Castile and León, Extremadura, and Andalusia.
“We continue to work in coordination with companies in the sector to gradually restore service throughout the peninsula.”
The operator has said that it could take up to 10 hours to restore power.
Portuguese grid operator REN added: “REN is in permanent contact with official entities, namely the National Civil Protection Authority.
“At the same time, the possible causes of this incident are being evaluated.
“All plans for the phased restoration of energy supply are being activated, in coordination with energy producers.”