Employees on the best way of examine electrical substation following a hearth at {an electrical} substation supplying energy to the ability, in London, United Kingdom on March 21, 2025.
Rasid Necati Aslim | Anadolu | Getty Photos
A hearth that shut Heathrow airport in March, stranding hundreds of passengers, was attributable to Nationwide Grid’s failure to keep up an electrical energy substation, an official report mentioned on Wednesday, prompting the vitality watchdog to open a probe.
The closure of Heathrow, the busiest airport in Europe, price airways tens of thousands and thousands of kilos. It additionally raised questions concerning the resilience of Britain’s infrastructure.
Vitality minister Ed Miliband mentioned the report was “deeply regarding”.
The report follows a overview of the incident on March 21 by the Nationwide Vitality System Operator, which manages the electrical energy community and was separated from Nationwide Grid final yr.
Because of the report, Britain’s vitality regulator Ofgem launched an enforcement investigation into Nationwide Grid Electrical energy Transmission, which owns and maintains the high-voltage electrical energy transmission community in England and Wales.
The report mentioned its overview had seen proof {that a} “catastrophic failure” on one of many transformer’s excessive voltage bushings at Nationwide Grid Electrical energy Transmission’s 275kV substation triggered the transformer to catch fireplace.
“This was most definitely attributable to moisture getting into the bushing, inflicting {an electrical} fault,” it mentioned.
It mentioned Nationwide Grid controls in place weren’t efficient and didn’t determine that motion had not been taken in relation to an elevated moisture studying in 2018.
A Nationwide Grid spokesperson mentioned that the corporate had a complete asset inspection and upkeep programme in place and that it had taken additional motion for the reason that fireplace.
“There are essential classes to be learnt about cross-sector resilience and the necessity for elevated coordination,” the spokesperson mentioned.
Ofgem mentioned the overview had “established that the foundation reason for the fireplace was a preventable, technical fault”.
It plans to overview whether or not Nationwide Grid complied with the related laws and licence situations referring to the event and upkeep of its electrical energy system near Heathrow.
The regulator may even fee an impartial audit into Nationwide Grid property to overview whether or not the failings have been a one-off or systemic, it mentioned.
Keep forward of the curve with NextBusiness 24. Discover extra tales, subscribe to our e-newsletter, and be a part of our rising group at nextbusiness24.com