Spain's national grid operator Red Eléctrica de España has ruled out a cyberattack and pointed to a drop in solar generation as the preliminary cause of the country's power outage, El Pais reports.

Electricity was back in most of the two countries almost 18 hours after a blackout that shut down much of daily life. The cause of the outage remained unclear.

No electricity, no communication, and in some cases, no running water – that was the situation from around 11:30am yesterday in Portugal and Spain, following a widespread blackout. Many people were unable to work,