Europe's ageing power grid and lack of energy storage capacity will require trillions of dollars in investments to cope with rising green energy output, increasing electricity demand and to avoid blackouts.

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.

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