However, the Jacobs report, titled Operational Risk: Ground Infrastructure Heathrow Airport, stated: “Beyond the management of supply and grid services, which lie outside the airport’s control, the responsibility for managing electricity supply risk lies with the airport and businesses operating from the airport.
“While some services can be temporarily supported with generator or battery back-ups, the key weakness is the main transmission line connections to the airport.”
It warned: “Outages could cause disruption to passengers, baggage and aircraft handling functions and could require closure of areas of affected terminals and potentially the entire airport.
“Even a brief interruption to electricity supplies could have a long-lasting impact as systems can take time to recover.”
The fire destroyed a vital transformer at the North Hyde substation and a back-up transformer, rendering the substation inoperable.
The airport is also served by two other substations powering different areas. However, in order for these to run the entire airport, the power supply to all the terminals needs to be re-engineered.
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While this is happening, Heathrow relies on its back-up supply, which is not sufficient to run the entire airport.
Warnings were also raised in 2022 about demand outstripping supply at the substations supplying Heathrow.
A London Assembly briefing paper, prepared by SSE Networks and seen by the London Telegraph, detailed how heavily the North Hyde substation was being used.
An upgrade project was planned to add another 22 MVA of capacity to the substation, although no date was given.
Heathrow’s operations began to return to normal following its reopening on Friday night.Credit: AP
Kathryn Porter, an independent energy consultant, criticised Heathrow’s reliance on only one exterior source of power, saying: “The risks associated with only having one grid connection have been known for more than a decade, but not mitigated effectively.”
Porter, who runs Watt-Logic consultants, also questioned why on-site generation was too low and criticised the time it took Heathrow to start up its back-up power supplies in response to the North Hyde substation failure.
She told GB News: “They don’t have different sources of generation, they have substations.
“One substation failed and it took out a second substation on Heathrow’s site, but two substations remained and they needed to reconfigure to run the site. It’s inadequate to not be able to maintain the site when one of your substations goes off.
British Airways says it expects “to run a near-full schedule” from Heathrow on Sunday.Credit: AP
“They should have on-site generation. They should have diesel back-up that can power the airport in the way data centres do.”
A second report, written just four years ago, also warned that without major infrastructure investment following the loss of revenue to Heathrow from the global COVID-19 shutdown, the airport faced a threat to its resilience.
Heathrow’s own revised business plan warned in June 2021 that underinvestment would “result in unacceptable risks that could threaten major erosion to service and resilience and potentially even the safe operation of the airport”.
The report warned that without more flexible investment rules by the Civil Aviation Authority to allow additional private investment into the airport, the result would be “materially worse consumer outcomes as key projects are deferred”.
It stated: “After two years of underinvestment in assets in order to protect liquidity, we risk less reliable services and more major failures”.
Lord Toby Harris, head of the Preparedness Committee, said: “Something so critical to the UK economy as Heathrow Airport should have had both contingency arrangements in terms of emergency power – is it really so dependent on one single substation? That’s a failure in itself.”
Surinder Arora, chairman of the Arora Group and founding member of the Heathrow Reimagined campaign, said: “This matter has been an embarrassment for the whole nation.
“A full investigation must be held at the earliest opportunity, and at the heart of that must be how Heathrow can be so reliant on any single site or source for power.”
The National Grid said in an incident update on Saturday morning (local time) that it was “now implementing measures to help further improve the resilience levels of our network”.
Heathrow’s own revised business plan warned in June 2021 that underinvestment would result in unacceptable risks.Credit: AP
‘Near-full schedule on Sunday’
British Airways says it expects “to run a near-full schedule” from Heathrow on Sunday, and passengers should go to the airport as normal, unless told otherwise.
A statement from the airline said: “We’ve been able to deliver around 90 per cent of our Saturday flying schedule, which means the vast majority of our customers were able to get to where they needed to be despite the very challenging circumstances going into the start of the day.
“As things stand, we’re anticipating being able to run a near-full schedule on Sunday and would therefore ask customers to come to the airport as normal, unless we get in touch to tell them otherwise.
“We’re really grateful to our customers for bearing with us over the past couple of days, even though many of them have had their travel plans unacceptably cancelled or disrupted.
“We’d also like to thank the thousands of colleagues who have worked so hard to support customers and help get our operation back on track.”
The Telegraph, London