Spain's grid operator has countered a government report attributing April's Iberian Peninsula blackout to miscalculation of the energy mix.

MADRID (Reuters) -Spanish grid operator Redeia will release its own report on the causes of the massive blackout that hit the Iberian peninsula on April 28, its chair, Beatriz Corredor, told a news briefing on Wednesday.

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.