Electricity is pulsing through Spain and Portugal again after a massive outage knocked out power in both countries on Monday. So too are questions.

Spain’s high-voltage electricity grid suffered more power generation disruptions than previously known ahead of the country’s largest ever blackout, the government said.

Portuguese grid operator REN will allow utilities to resume imports of electricity from Spain, but the transmission capacity will be limited to around one-third of the levels seen before the huge power blackout in the two countries on April 28.