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.

Spanish grid operator Redeia blamed power plants for the massive blackout that affected the Iberian peninsula in April, as it disputed a government report that said its failure to calculate the correct energy mix was a key factor.

An investigation into April's massive blackout across the Iberian peninsula revealed Spain's grid operator REE underestimated its power capacity needs. The oversight resulted in insufficient thermal power stations being online during peak hours,