The British energy secretary has contributed to the long disruption at Europe's busiest air travel hub, and said the fire at the electrical substation that crippled Heathrow Airport has removed one of the main backup systems designed to keep electricity running.
“We had a backup generator, and it was affected by the fire. This gave us a sense of how unusual and unprecedented it was,” UK energy secretary Ed Miliband said in an interview on Sky TV early Friday.
Miliband said the National Grid, which operates a failed transformer near the airport, is about to pass through a second backup system, but it has proven to be difficult given the scale of the fire at the substation.
The transformer converts current from voltage to low voltage. In the case of the transformer that caused the fire, experts said they had apparently changed 275,000 volts to 66,000 volts when it failed. London Fire Force vice-chairman Jonathan Smith said the flames had a connection to a “transformer made up of 25,000 liters of cooling oil completely down at the substation.”
By early Friday afternoon, National Grid officials said the network at the Northhide substation where the fire broke out had been reconfigured to restore power.
“This is a temporary solution and we'll be doing more work at Northhide to bring the substations and network back to normal operation,” the utility said.
It could be at the heart of questions about the reliability of UK infrastructure after a fire and airport closures, as at least one backup system failed to recover power quickly after such a major outage. These questions began within hours of shutdown. In a social media post, Willie Walsh, director of the International Air Transport Association, the global trade association of airlines, wrote, “What about critical infrastructures that are important domestically and globally rely entirely on a single power source without alternatives?”
“If that's the case – so that you can see it,” he added. “It's a clear failure of the airport's plan.”
Miliband said the government understood the cause of the suspension and told Sky TV:
National Grid officials did not immediately respond to emails requesting information about the backup system.
In a statement, Heathrow Airport said the facility has “multiple energy sources” but there was no backup to provide enough power to operate the entire airport. The statement said the backup diesel generator and easy-to-run power source would kick, allowing the plane to land and passengers to disembark. But they wouldn't have been enough to get the airport to work perfectly.
Simon Gallagher, a former senior executive at the UK's largest power provider, said he believes that the substation near Heathrow is designed so that if there is a problem with the first transformer, the second transformer is designed to kick quickly. However, he said the fire seemed to have been furious through the prevention system and damaged both transformers.
That's very unusual, he said. He shows a series of failures to a fire control system designed to quickly reduce power to failed transformers to avoid such damage.
“We basically designed things so that something would fail,” said Gallagher, now managing director at UK Networks Services. But he added, “To make it fail, and because it also damages the one next to it, a lot must have been wrong.
Police say counter-terrorism investigators will investigate possible sabotage. But Gallagher said the incident appears to him as a “classic transformer fault,” judging from video footage from the scene.
The incident raised questions about whether the airport had a backup generator operated with batteries or gas.
Gallagher said that it is not possible given Heathrow's current system. This cannot provide enough energy to maintain all the lights if the regular connection to the airport's electrical grid is broken.
The emergency generator system mentioned in the Heathrow statement said it was designed to operate the runway lights and control tower systems, even during incidents like the one that took place on Friday.
However, he said it was impossible to keep the planes arriving because there was no electricity to move their luggage, light the terminal or operate the doors. To do that, you'll need at least 20 large diesel generators, the size of a 40-foot shipping container, each capable of generating a large amount of electricity.
Heathrow had no such system. This would have been able to maintain power throughout the airport for about six hours before refueling was needed, he said. However, he added that other major power customers, such as data centers, have installed large backup generators to ensure power in emergencies.
“I think things will change,” Gallagher said. “I think Heathrow and other airports will set up a generation of backup.”
A decision to do so may oppose questions about environmental impact. Heathrow officials have worked towards the “net zero” goal for many years by increasing the efficiency of planes landing at airports and reducing ground infrastructure and vehicle emissions.
Gallagher said none of these efforts caused confusion on Friday or prevented the faster return of power, despite some claims circulating on social media.
