Firefighters in Hayes, west London, got the call to investigate smoke billowing out of the area’s North Hyde power substation around 11:20pm on Thursday, and raced to the site located less than two miles from Heathrow airport.
Within hours, one of the world’s busiest airports was closed to all air traffic, incoming planes from as far as New Delhi and Los Angeles were turning back, and the recriminations had begun.
“How is it that critical infrastructure — of national and global importance — is totally dependent on a single power source without an alternative,” asked Willie Walsh, director-general of International Air Transport Association, the airline lobby, and a former chief executive of British Airways, who has been a long-standing critic of the airport. “If that is the case — as it seems to be — then there is a clear planning failure by the airport.”
The question of how a fire at a single substation could bring one of the world’s biggest airports to a halt echoed around Whitehall.
While the cause of the ignition is not known, the ferocity of the blaze fuelled by 25,000 litres of cooling oil inside the substation’s transformer appears to have been enough to damage backup transformers on site.
That was enough to knockout the whole substation which supplies electricity to terminals 2 and 4 at Heathrow as well as lighting on the runways, triggering such disarray at the airport it decided to close entirely.
Heathrow’s diesel-fired backup generators worked as planned. But these are in place to make sure it can do the basics such as landing planes and evacuating passengers, rather than run a full operation.
“It’s not possible to have back up for all of the energy we need to run our operation safely,” Heathrow said.
Shortly before 2pm, engineers at National Grid and Scottish and Southern Electricity Networks, said they had reconfigured the substation so that it was capable of supplying power to Heathrow again.
But it took several hours for the airport to be satisfied that its power source was reliable, and that its electronics were safely back online. By just after 4pm the airport announced plans to reopen, and the first flights were scheduled to take off from around 7pm.
Pressure is growing on Heathrow to explain why it allowed itself to become so exposed to a single point of failure.
Dieter Helm, infrastructure expert at Oxford university, said it was a “huge wake-up call about the lack of resilience in all our critical infrastructure and its interdependence”.
“Just as the UK and Europe have had a massive wake-up call on defence, it’s blindingly obvious that the energy infrastructure is target number one. You need a lot more resilience in the energy system if you face a serious security threat.”
Thomas Woldbye, Heathrow’s chief executive, insisted that the airport’s contingency planning had worked.
He said the airport could run on power from the remaining two of the three substations it takes power from, but migrating its electronic systems over to the restructured power supply “takes time”.
Woldbye said: “We lost a major part of our power supply . . . this has been an incident of major severity. We have lost power equal to that of a midsized city and our backup systems have been working as they should, but they are not sized to run an entire airport.”
Heathrow airport, which is privately owned by a consortium of investors, is saddled with more than £19bn of debt, and has long faced questions from airlines over its finances and whether it has efficiently invested in its infrastructure.
Experts added the fire underscores the need for the government to oversee critical infrastructure in the UK, more of which is privately owned than in any other country worldwide. The UK’s electricity, gas, telecoms and water networks as well as ports and airports are all in private hands.
Noble Francis, economics director at the Construction Products Association, said: “Companies tend to spend on maintenance, renewals and expansion in capacity but for fundamental infrastructure there needs to be significant investment in resilience and contingency so they can deal with big one-off disruptions.”
The incident comes as the UK is set to rely more heavily on electricity networks as it tries to move towards electric cars and heat pumps powered by renewable energy, as part of the shift away from fossil fuels. Huge new capacity is needed to connect new wind farms and solar farms to homes and businesses.
The electricity networks around west London have been the subject of intense scrutiny over recent years as capacity has failed to keep up with demand. Housebuilders have been warned of lengthy delays to projects as power-hungry data centres set-up near fibre-optic cable lines.
Tony Travers, professor at the London School of Economics, said the incident begs the question of “whether there are other national infrastructure assets that are this vulnerable to a one-off incident and which part of government is responsible for the regulatory oversight, even if they are privately owned.”
Passengers delayed around the world have a more urgent question: when will they get in the air? “We’re stuck here with no alternative but to eat in the hotel,” said Sarah Jones, a retiree set to fly to Singapore with her husband, at the Sofitel hotel near Heathrow. “Breakfast costs £66 for two . . . and prices are going up as we speak.”
Additional reporting by Akila Quinio at Heathrow
