The chief executive of UK electricity supplier the National Grid has confirmed that Heathrow Airport had sufficient power during last week's outage, emphasising that the energy network remained fully capable of supplying the airport’s electricity needs throughout the day.
National Grid chief executive John Pettigrew told the Financial Times that while the “unprecedented” fire disabled the North Hyde substation, two other substations serving Heathrow were fully functional throughout the incident.
The fire at the West London electrical substation caused the cancellation of over 1,300 flights to and from Heathrow on March 21, 2025. In addition, over 200 flights were forced to land in cities around the world such as Amsterdam, New York, Frankfurt and Calgary. Dozens of flights were also made to return to their origin airports. Heathrow reopened later in the day, operating a very limited flight schedule at Terminals 3 and 5, with British Airways operating several long-haul services to destinations such as Riyadh and Cape Town.
Throughout the day, airlines operating from Heathrow were expected to transport more than 291,000 passengers.
“This was not a decision we took lightly,” said Thomas Woldbye, CEO pf Heathrow Airport. “The scale of the fire at an off-airport power substation was significant, impacting a large area of West London. It is inevitable that an incident of this magnitude would affect our operations. I hope people will understand all our decisions and actions were to ensure the safety of our passengers and colleagues,” Woldbye stated in a social media post.
The airport boss also recognised the impact the closure had on passengers, airlines, and airport workers.
“There was no lack of capacity from the substations,” Pettigrew told the Financial Times. “Each substation individually can provide enough power to Heathrow.”
The National Grid said on March 21, that it was able reconfigure its electricity supply to restore power to parts of Heathrow Airport affected by the outage but described the move as an "interim solution" while further work was carried out to fully resolve the issue.
In response to comments made by Pettigrew, a Heathrow spokesperson told Airline Economics: “Pettigrew’s 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”
The airport reaffirmed that its objective was to reopen the airport as soon as safely and practically possible after the fire, further confirming that over the weekend, the airport operated a full schedule of over 2500 flights, serving over 400,000 passengers.
British Airways, which has the largest share of Heathrow flights, said in a social media post that it was able to deliver around 90% of its flying schedule one day after the closure. Virgin Atlantic also confirmed that its operations had “fully stabilised” following the power outage.
However, some operators have voiced frustration at the suspension of all operations at the airport. “I’m afraid I can’t find a reason to congratulate Heathrow Airport for the closure of the largest (and one of the most expensive) airports in Europe and leaving your customer airlines with tens of millions of pounds in extra costs and huge losses and passenger disruptions,” said Conor McCarthy, executive chairman at Emerald Airlines & Dublin Aerospace
“To have a single point of electrical failure render all air services and terminals useless is surely a complete failure of airport operational management. Heathrow should surely be liable for all costs here,” McCarthy said.
UK energy minister Ed Miliband, who previously described the sub-station fire as “catastrophic”, noted that he has commissioned the National Energy System Operator (NESO) to carry out an investigation into this specific incident and to understand any wider lessons on energy resilience for critical national infrastructure, both now and in the future.
Heathrow again confirmed on March 24, 2025, that it is now back running a full schedule.