The blackout that engulfed the Iberian Peninsula on Monday was chaotic and stressful for many. But it had a silver lining.

That conclusion has been supported by the operator of Spain’s national grid, Red Eléctrica, which has located where outages began on Monday. Two separate incidents of power outages led to instability in the grid leading to a “breakdown in interconnections with France,” leaving the Iberian grid isolated.

Power started returning to parts of the Iberian peninsula late on Monday after a huge outage brought most of Spain and Portugal to a standstill, grounding planes, halting public transport, and forcing hospitals to suspend routine operations.