What caused the blackout in Spain and Portugal and did renewable energy play a part?

Passengers roam outside Atocha train station during the nationwide power outage in Madrid on Monday. Picture: AP Photo

Spain and Portugal suffered the worst blackout in living memory in Europe this week. About 55m people were affected and it lasted more than half a day. Some have blamed renewables and net zero emissions targets, as the two countries boast high levels of wind and solar on their electricity grid and lead Europe in the technologies. But is this true?

What happened?