The sweeping power outage that hit Spain and Portugal this week has raised questions about the electricity grid in a region not normally known for blackouts.

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.

The massive power outage on the Iberian Peninsula has cost at least three lives. The search for the cause of the outage continues.