The Director General of the National GRID confirmed that the power was available to keep Heathrow open throughout Friday closure.
In an interview with Financial Times, John Pettigrew said that the fire that had eliminated a “unique event”, but that two other substations had remained operational and capable of propeling western airport.
Heathrow’s managing director Thomas Woldbye said on Friday that the closure was not caused by a lack of power, but was due to the time it took to go from damaged substation to the other two.
The airport is under pressure from the airlines to explain why the flights were suspended for 18 hours after the fire in the early hours of Friday morning.
The fire began in a transformer in the electrical substation in Hayes, north of Heathrow, around midnight.
The airport offers emergency emergency power supplies, which use generators and diesel batteries, but they only do crucial safety systems, such as landing and track fire equipment.
A separate biomass energy generator also provides heat and electricity to Terminal Deux.
However, the national network is the main source of power for Heathrow.
Mr. Pettigrew told Financial Times, of which he did not remember a transformer who had failed such an extent in his 30 -year career in industry.
“Losing a substation is a unique event, but there were two others. It is a level of resilience.”
A Heathrow spokesperson said Mr. Pettigrew’s comments confirm that it was an unprecedented incident and that he would not have been possible for Heathrow to operate without interruption.
“Hundreds of critical systems across the airport were to be provided safely, then restarted in complete safety and systematic,” she said.
“Given Heathrow’s size and operational complexity, the safe restarting of operations after a disturbance of this magnitude was an important challenge.”
On Friday, Heathrow directors decided to close the airport for security land while they went to national national network supplies.
Woldbye told the BBC that the reopening delay was due to the need to “reallocate” the power supply – “the closure and restart of the systems that take a lot of time”.
He said there were “a number of systems that we have to close and bring them back and bring them back and ensure that they are safe”.
“These are food systems, its bridges, its mechanical stairs, all these systems must be raised, tested to ensure that they are safe.”
He added that there were risks “of certain sizes that we cannot protect ourselves 100% and it is one of them”.
However, the duration of the closure made the airlines furious.
Willie Walsh, former boss of British Airways and chief of air organization IATA said it was a “clear airport planning failure” and that power management systems and procedures were now in the spotlight.
The government has ordered a six -week investigation into the closure, led by the national operator of the energy system.
Woldbye, who sparked criticism for saying that the airport had “returned fairly quickly,” said that it was “happy” to answer the Prime Minister.
