A fire that shut London’s Heathrow airport in March, stranding thousands of people, was caused by the UK power grid’s failure to maintain an electricity substation, an official report said on Wednesday, prompting the energy watchdog to open a probe.
The closure of Heathrow, Europe’s busiest airport, cost airlines tens of millions of pounds. It also raised questions about the resilience of Britain’s infrastructure.
Energy minister Ed Miliband called the report “deeply concerning,” after it concluded that the issue which caused the fire was identified seven years ago but went unaddressed by power grid operator National Grid. Energy regulator Ofgem said it was “a preventable, technical fault.”
The report follows a review of the March 21 incident by the National Energy System Operator, which manages the electricity network and was separated from National Grid last year.
As a result of the report, Ofgem launched an enforcement investigation into National Grid Electricity Transmission (NGET), which owns and maintains the high-voltage electricity transmission network in England and Wales.
Heathrow said via email that it was considering whether it wanted to pursue legal action, and that it expected National Grid to take “accountability for these failings.” Heathrow itself, along with airline companies, could potentially face a hefty compensation bill for the disruption caused to travelers.
Full Audit
The report said a “catastrophic failure” on one of the transformer’s high-voltage bushings at NGET’s 275 kilovolt substation caused the transformer to catch fire, most likely due to moisture entering the bushing, sparking an electrical fault.
Despite detecting an elevated moisture reading in one of the bushings in 2018, which indicates an imminent fault that requires the component to be replaced, the company did not fix the issue, the report said.
