By Pietro Lombardi MADRID (Reuters) -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.

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.