An official report found that insufficient voltage control in the power grid led to the blackout on April 28, severely affecting electricity supplies.

Spain's Energy Minister Sara Aagesen said the inability of power plants to adjust voltage caused the massive blackout on April 28 that affected Spain and Portugal. The investigation report revealed that the plants, paid to maintain voltage control, failed to absorb the necessary reactive power. The incident led to severe outages, leaving thousands of people stranded in trains and elevators. The investigation found no evidence of a cyber attack.