Spanish authorities say the massive power outage in April across Spain and Portugal was due to technical and planning errors that led to a cascade of failures in the grid.

Spain's power grid operator and the country's electricity companies traded blame on Wednesday over the April blackout that crippled the Iberian Peninsula, a day after a long-awaited government report highlighted their responsibility.

A government investigation into the massive blackout that struck the Iberian Peninsula in April has determined that a voltage surge in the power grid triggered a chain reaction that led to widespread disruptions,