Heathrow Blackout Exposes Weak Spot In Airport’s Power Supplies

London Heathrow's unprecedented blackout on Friday has put the airport's reliance on potentially vulnerable infrastructure into focus, at a time when the biggest UK hub is lobbying for an ambitious expansion plan. 

A fire late Thursday at a nearby electrical substation cut off the power supply to Heathrow, bringing flights to a standstill for almost all of Friday. While backup systems kicked in, they only allow the hub to land some aircraft and evacuate passengers, but not to support full operations. Only by late on Friday did a few flights resume, mainly to repatriate dislocated passengers.

Smoke from a fire at North Hyde Electricity Substation near London Heathrow Airport in London on March 21.

The public blowback to the outage was swift, with Willie Walsh, the former chief executive officer of British Airways parent IAG SA and now IATA director, saying it's “yet another case of Heathrow letting down both travelers and airlines.” 

Walsh said it's a “clear planning failure by the airport” if critical national infrastructure relies on one energy source without an alternative. 

At the same time, given that Europe's busiest airport uses as much energy as a small city, keeping enough power capacity in reserve to meet such demand is complicated. Heathrow hasn't suffered an outage on that scale in at least two decades, with previous disruptions typically caused by strikes, weather, or air-traffic control computer glitches.

“Lots of people would say it seems like a greater level of redundancy could have been built in, but ultimately you have to pay for that,” said Robin Preece, a lecturer in future power systems at the University of Manchester. “It's a question of how much you're willing to pay for situations which are unlikely to arise.”

A traveler at Terminal 5 on March 21.

Airports around the UK are connected to substations in a similar way to Heathrow, and it's not unusual for some to be dependent on a single source, Preece said. What's different this time is the fire and catastrophic failure that ensued, Preece said in an interview.

While infrequent, such fires can be caused by various factors, said John Loughhead, an electrical engineering expert at the Institution of Engineering and Technology. Some equipment in the substations, such as oil and circuit breakers, are flammable or can trigger explosions.

“It is surprising that, as a part of our national critical infrastructure, Heathrow does not have an alternative supply point in case of accidents like this,” he said in an email.

The incident comes at a time when Heathrow is trying to position itself for expansion and remain competitive against other international hubs like Dubai and Paris. Heathrow recently got the go-ahead from the UK government to build a third runway, a concept that has been considered for decades, in a bid to increase passenger numbers.

A British Airways aircraft at London Heathrow Airport in London on March 21.

Heathrow is also installing next-generation luggage scanners across the security lanes in all of its terminals. The airport is set to miss the government deadline in June which was already extended by a year, Bloomberg News reported earlier this month.

The fallout from Friday's blackout would have been worse still had Heathrow already had a third runway, said Guy Gratton, associate professor of aviation and the environment at Cranfield University. There's currently little spare capacity across UK airports to help accommodate disrupted passengers from Heathrow's shutdown, he said.

“Heathrow runs at near 100% saturation,” Gratton said.