The massive power cut that plunged huge swathes of Spain and Portugal into chaos earlier this year was caused by a miscalculation, the Spanish government has said.
Airports, trains and internet were among the services affected by the blackout in late April, with traffic lights also down - causing huge tailbacks.
Millions of people were affected and parts of the two countries were brought to a standstill as authorities raced to find the source of the problem.
There was discussion about whether a cyberattack was to blame, but today Spain's energy minister said the issue was a miscalculation by the Spanish power grid operator REE.
Sara Aagesen said REE did not have enough thermal power stations switched on during peak hours of April 28 when the surge caused a chain reaction leading to the power outage.
"The system did not have sufficient dynamic voltage control capacity," she said.
Read more from Sky News:
Air India flight from Ahmedabad to London cancelled
Assassination suspect captured after two-day manhunt
The government report, which was due to be made public on Tuesday, found that some of the power plants required by law to regulate the grid's voltage failed to do so.
Electricity grids in Europe are kept at 50 Hertz frequency in order to maintain stability - and even a slight deviation can lead to damage.
Power plants "should have controlled voltage and, moreover, many of them were economically remunerated to do so. They did not absorb all the reactive power that was expected in a context of high voltages," Ms Aagesen said.
The investigation found no evidence of a cyberattack, she added.
(c) Sky News 2025: Cause of massive power cut that plunged Spain and Portugal into chaos revealed
Trump's words designed to stoke tension, confuse and apply intense pressure on Iran
Israeli tanks kill 51 people waiting for aid in Gaza, Hamas-run health ministry says
The one 'bunker buster' bomb that could be used to hit Iran's secretive Fordow enrichment plant
Ukraine war: 14 killed as Russian missile and drone attacks strike Kyiv - including American citizen
Austria gunman had 'significant passion' for school shootings, police say
French police fire tear gas at migrants – as No 10 admits Channel crisis 'deteriorating'
Double shooting suspect 'fled through three countries in 15 hours', Spanish police claim
Air India flight from Ahmedabad to London cancelled days after fatal crash
Family describe 'disbelief' after man's wife and two daughters killed in Iranian strike on Arab Israeli town
