Europe's aging 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.

A week ago, Spain and Portugal lost power in their worst blackout. Authorities are investigating the cause, but whatever the findings, analysts and industry representatives say infrastructure investment is essential.

"The blackout was a wake-up call. It showed that the need to modernize and reinforce Europe’s electricity grid is urgent and unavoidable," Kristina Ruby, secretary-general at Eurelectric, Europe's electricity industry association, said.