UK power bosses had boasted that a huge outage like the one that crippled Heathrow would happen only once every 346 years.
Their bold prediction came under scrutiny after Friday night’s fire at a substation brought Europe’s busiest airport to a standstill.
AFPSmoke billows from a substation supplying power to Heathrow Airport[/caption]
APHuge flames rising from the North Hayes substation[/caption]
GettyNational Grid chief executive John Pettigrew is facing growing demands to explain how the blaze could cause so much trouble[/caption]
PAHeathrow chief executive Thomas Woldbye told BBC Radio Four that he was ‘personally quite proud’ of how the airport responded to the outage[/caption]
According to a grid reliability assessment produced in December using National Grid data, the network in the West London area was deemed to be “highly reliable”.
The environment report, compiled by a consultancy agency for a new data centre opened near Heathrow, said the area supplied by the North Hyde substation had a reliability level of 99.999605 per cent.
A similar National Grid report from 2022-2023 calculated that the overall reliability of the country’s supply was 99.999997 per cent.
It equates to the probability of a one-minute outage happening once in 5.8 years and a one-hour outage occurring once in 346 years.
The substation was the site of an enormous blaze on Thursday night with 25,000 litres of cooling oil igniting in a fireball, although the cause of the fire is still unknown.
It forced Heathrow to shut down for 18 hours, causing travel misery for 300,000 passengers.
Heathrow yesterday said it was fully operational after Friday’s disruption — but passengers were still warned to expect delays.
More than 100 flights arriving and departing were cancelled.
Farah Rafeeq, 24, was due to fly with Singapore Airlines on Friday with her pregnant friend Niken Wulan, 32, to a wedding on Sunday.
She said: “The last few hours have been nightmarish because it is one of our closest friends’ wedding and we have to travel for at least 20 hours to get there.
“We had to pay double the amount, between £600 and £700, for the new flight, and we had planned this trip for months and had hotels booked and are flying to South-East Asia after the wedding.”
The statistics in the reports heaped further pressure on under-fire National Grid chief executive John Pettigrew, who is facing growing demands to explain how the blaze could cause so much trouble.
Mr Pettigrew is paid £7.2million a year. It includes almost £6million in bonuses and incentives and making him one of the highest paid energy executives.
National Grid issued a grovelling apology yesterday, saying it was working to “improve the resilience” of the network after the failure.
The privately owned company, which is the UK’s largest electricity distribution network, said: “We are deeply sorry for the disruption caused and are continuing to work closely with the Government, Heathrow and the police to understand the cause of the incident.”
It did not respond to The Sun on Sunday’s enquiries about its reliability figures.
LNPFlights have now resumed for passengers at Heathrow[/caption]
‘Key weakness’
Yesterday it emerged that Heathrow was warned in 2014 that the reliance on certain electricity lines into the site was a “key weakness”.
The report, written by consultants Jacobs and published by the Government, stated that even a brief interruption to supplies could have a “long-lasting impact” on systems.
But Heathrow chief executive Thomas Woldbye told BBC Radio Four yesterday that he was “personally quite proud” of how the airport responded to the outage.
He said the incident was “as big as it gets for our airport” and that “we cannot guard ourselves 100 per cent”.
Mr Woldbye has not revealed publicly how much he is paid but his predecessor John Holland-Kaye had a £6.4million final pay deal, which included a £2.67million termination package.
Electrical substations are designed to convert and distribute electricity at suitable voltage levels.
Heathrow uses three substations, each with a back-up, and consumes as much energy as a small city.
Fires at substations are rare but not unheard of.
There have been at least four so far this year already, albeit on a smaller scale to the Hayes inferno.
The last few hours have been nightmarish because it is one of our closest friends’ wedding and we have to travel for at least 20 hours to get there
Farah Rafeeq
They are often triggered by equipment failure or external events such as weather incidents.
Counter-terrorism officers from the Metropolitan Police initially led the investigation before the force confirmed the fire was believed to be non-suspicious.
London Fire Brigade has now taken over and will focus on the electrical distribution equipment.
Residents living near the substation claimed they had never seen any security staff guarding the crucial infrastructure.
Ramandeep Singh, 38, said: “I don’t see anyone in high-viz.
“The door is closed, but no one is ever in there.”
A mum of two, who asked not to be identified, said: “I had just gone to bed when they knocked on the door and said, ‘You have to go’.
“We all stood out on the street for hours, 200 people.
“The power in the house was all gone, the streetlights weren’t working so it was so dark.
“I have lived in the area for 20 years and I never see anyone working there.
“I have never noticed security or CCTV although it is locked up.”
Labour MP Ruth Cadbury, chairwoman of the Transport Select Committee, said yesterday that there was a lack of power grid capacity in the area surrounding Heathrow.
No new overhead lines are expected until 2036.
She blamed a lack of interest in improving infrastructure during the last Government and said that the priority was now working to “ensure our key national infrastructure is fit for purpose”.
Former Transport Secretary Ruth Kelly, an independent member of Heathrow’s board, will undertake a review of the airport’s crisis management plans and its response to the power outage, said the airport’s chairman, Lord Deighton.
Additional reporting: Eleanor Gunn and Brendan McFadden
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