Britain struck by unusual power activity hours before blackouts in Spain and Portugal

The UK was struck by unusual power activity hours before large swathes of Spain and Portugal were hit by blackouts, it has emerged.

Britain’s grid operator has confirmed it is investigating unexplained changes in electricity frequency seen early on Sunday morning and also in the evening. The system’s frequency must be kept within specific limits for the lights to remain on.

Control room staff noticed the first incident at around 2am at the Keadby 2 gas-fired power plant in Lincolnshire, as well as the Viking Link interconnector between the UK and Denmark. Then, power plant failures were again seen at around 6pm.

National Energy System Operator (Neso), the quango that operates Britain’s grid, has confirmed to The Independent that officials are investigating the unexpected activity, with the cause still unknown. It is thought that there was a disconnection from the network in both instances, which was contained by control room engineers each time.

However, a spokesperson said it is “highly unlikely” the events over the weekend are connected to each other or to the massive system failures that hit the electricity network in Spain, Portugal and parts of France on Monday.

They added that it is “standard practice” to review events such as those that affected Britain’s grid on Sunday and that there was no impact to electricity supplies or consumers, with the issues resolved the same day.

Just hours after the second unexplained power failure in Britain, at around 11.30am on Monday, one of Europe’s most severe blackouts plunged most of the Iberian peninsula into darkness.

Spain and Portugal both declared a state of emergency as the lives of tens of millions of people were upended for hours, with traffic and transport brought to a standstill and many left without water, Wi-Fi or mobile network.

Power has now returned to households in both countries – but investigators are still looking into the cause of the blackout, which remains unclear, although authorities denied foul play and rumours of a cyber attack.

"What happened yesterday cannot ever happen again," Spanish prime minister Pedro Sanchez said on Tuesday afternoon, vowing to hold private operators to account.

NESO confirmed that Britain's electricity network was not affected by Europe’s power system incident, with the grid operating under different conditions that can protect it from issues the continent might be facing.

A spokesperson said: “As a prudent system operator we review all generator trips and events on our network as standard practice. We are still reviewing operational events across the weekend. However, it is highly unlikely that these events are connected to each other or related to the events on the European electricity network on Monday.

“Great Britain's electricity network was not affected by the power system incident on the European electricity network on Monday. We are working closely with our counterparts across Europe to understand the cause of the power system incident and to offer our support. It is too early to comment further on these events and whilst investigations are still ongoing.”