Trigger suspected to be one substation https://www.reuters.com/business/energy/power-generation-los... The blackout itself is suspected to be amplified by ren https://montelnews.com/de/news/96607ac1-dd73-4c23-bb47-a7c2a... "Die Experten betonen, dass erneuerbare Anlagen das Problem nicht nur nicht abfedern konnten, sondern möglicherweise verstärkt haben."

And RE is running the grid in "strengthened mode". There were no comments about what this means, but looking at the data, gas+nuclear are modulated less vs usual, regardless of ren generation https://app.electricitymaps.com/zone/ES/72h/hourly