National Grid boss claims Heathrow had 'enough power' despite shutdown

24 March 2025, 01:51 | Updated: 24 March 2025, 10:02

The chief executive of National Grid has claimed that Heathrow Airport had enough power from other substations despite Friday's shutdown.

Around 1,300 flights were affected after a fire knocked out an electricity substation in Hayes on Thursday evening. Operations were not able to resume until Friday evening.

John Pettigrew from National Grid said there were two other substations "always available for the distribution network companies and Heathrow to take power".

In his first comments since the disruption, Mr Pettigrew told the Financial Times: "There was no lack of capacity from the substations.

"Each substation individually can provide enough power to Heathrow."

He added: "Losing a substation is a unique event - but there were two others available.

"So that is a level of resilience."

In response to the comments, a Heathrow Airport spokesperson said: "As the National Grid's chief executive, John Pettigrew, noted, he has never seen a transformer failure like this in his 30 years in the industry.

"His view confirms that this was an unprecedented incident and that it would not have been possible for Heathrow to operate uninterrupted.

"Hundreds of critical systems across the airport were required to be safely powered down and then safely and systematically rebooted. Given Heathrow's size and operational complexity, safely restarting operations after a disruption of this magnitude was a significant challenge."

Speaking to Wilfred Frost on Breakfast this morning, Transport Secretary Heidi Alexander said the decision to suspend flights at Heathrow on Friday was taken by the airport because it needed to reboot systems after switching to a different power supply.

She said she had had a conversation with Thomas Woldbye, the chief executive of Heathrow, on Friday morning.

"He told me that whilst there are multiple power supplies into the airport, the fire had created a very significant problem with respect to Terminals two and four specifically and that there had to be some reconfiguration of power supplies into the airport.

"That meant all the systems had to be turned off and all the systems had to be restarted again in a safe way."

Mr Woldbye previously said a back-up transformer failed during the power outage, meaning systems had to be closed in accordance with safety procedures so power supplies could be restructured from two remaining substations.

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But it has emerged that a report by consultancy firm Jacobs more than 10 years ago found a "key weakness" of Heathrow's electricity supply was "main transmission line connections to the airport".

The document, published in 2014, stated "outages could cause disruption to passenger, baggage and aircraft handling functions", and "could require closure of areas of affected terminals or potentially the entire airport".

In its appraisal of operational risk at the airport, Jacobs said provision of on-site generation and other measures to ensure resilient supply appeared "to be adequate" to enable Heathrow "to withstand and recover from interruptions to supply".

The report added that the airport operated "within risk parameters that are not excessive or unusual for an airport of its type".

Metropolitan Police counter-terrorism officers initially led the investigation but the force said the fire was not believed to be suspicious so the London Fire Brigade is now leading the probe which will focus on the electrical distribution equipment.

Heathrow is Europe's largest airport, with more than 83.9 million passengers travelling through its terminals in 2024. Around 200,000 passengers were affected by Friday's closure.