A major power outage that paralysed the Iberian Peninsula in April was caused by “overvoltage” on the grid that triggered “a chain reaction,” according to a government report released Tuesday, June 17th.
The blackout had “multiple” causes, Ecological Transition Minister Sara Aagesen told reporters following a cabinet meeting, adding the system “lacked sufficient voltage control capacity” that day.
Overvoltage happens when there is too much electrical voltage in a network, overloading equipment. It can be caused by surges in networks due to oversupply or lightning strikes, or when protective equipment is insufficient or fails. When faced with overvoltage on networks, protective systems shut down parts of the grid, potentially leading to widespread power outages.
Aagesen mentioned Spanish grid operator REE and certain energy companies she did not name that she said disconnected their plants “inappropriately… to protect their installations.”
The minister also cited “insufficient voltage control capacity” on the system that day, due in part to a programming flaw, but she stressed that Spain’s grid is in principle robust enough to handle such situations.
Due to these misjudgements “we reached a point of no return with an uncontrollable chain reaction” that could only have been managed if steps had been taken beforehand to absorb the overvoltage problems, she added.
The report comes after leaked recordings of conversations between Red Eléctrica (REE), the national electricity grid operator, and electricity operators were made public on June 9th.
Just 46 minutes before the blackout, an REE technician admitted the problem stemmed from solar energy “coming in and out” of the system due to price and adjustment issues.
