Heathrow Airport closed all day Friday 21 March 2025

[whole diary]

[Electric train]

A location of stratigic National importance such as Heathrow should have a robust backup system whilst they 100% may not be warranted they should be able to run core business at a acceptable degraded mode

As I said, the "robust back up system" did work, if an aircraft HAD to land at Heathrow last night it could have done so safely. Trying to keep an airport running when everything around it has failed is just asking for even more trouble. "Degraded mode" = what ?  Burger King open but not McDonalds ?

Strangely enough, before I retired, I actually worked at an airport setting to work a "robust back up system" such as is probably installed at Heathrow - albeit on a much larger scale at Heathrow. This was not designed to keep the airport restaurants running at that airport either.

My current job is looking after the traction power system for a large chunk of South London along with a number of major London stations.  There are always weak spots in a system especially older systems, the modern systems can operate a N-1 including a total loss of a National Grid connection in SE London, a reduced service would have to be implemented but it would not be a total shut down

Seems my option that Heathrow Airport should have been able to supply the Airport from the other 2 GSP as widely reported in the media is backed up by the boss of National Grid
https://www.bbc.co.uk/news/articles/cdjy4m0n1exo

There is no doubt a war of damage limitation of the 2 public listed companies going on to protect from reputational damage, political focus, not to mention the clams for costs from Airlines.

As I said in my original post on Friday, I am surprised the Heathrow were not able to reconfigure the supplies, something they should have been able to do that night, the only thing that then my have effected flights was the smoke from the fire.

[stuving]

Seems my option that Heathrow Airport should have been able to supply the Airport from the other 2 GSP as widely reported in the media is backed up by the boss of National Grid
https://www.bbc.co.uk/news/articles/cdjy4m0n1exo

There is no doubt a war of damage limitation of the 2 public listed companies going on to protect from reputational damage, political focus, not to mention the clams for costs from Airlines.

As I said in my original post on Friday, I am surprised the Heathrow were not able to reconfigure the supplies, something they should have been able to do that night, the only thing that then my have effected flights was the smoke from the fire.

One company that is keeping its head well below desk level is UKPN. They manage the distribution network at Heathrow, as an independent DNO^▸ (Distribution Network Operator) (or the equivalent). But they have put out some quite hubristic stuff about this role in the past, e.g. this:

Security and reliability of electricity is essential for all airports. Heathrow is no exception. Even an interruption of a few seconds could have a knock-on effect on baggage systems and cargo shipments. This could take many hours to resolve and lead to significant lost revenue and passenger disruption. Resilient power is also vital to the entire airport community: including passenger transport services, employees’ facilities, freight and cargo operators, passenger retail or restaurants, emergency services, rail links, and airlines themselves. 

Providing 24/7/365 resilient power to a global transport hub requires continuous innovation and dedication. This means around-the-clock maintenance, repairs, and renewals to thousands of high voltage electrical substations, transformers, relays, and more than 600km of cables...

Approach and innovation

As strategic energy infrastructure partner, our approach has been to work with Heathrow to deliver world-class performance every single day. The faultless maintenance of critical energy infrastructure of this scale and density is vitally important: the risks to people, property and businesses from electricity cannot be understated if not managed correctly.

... and a world class excuse generator?

[TonyK]

I think we are still in the phase of this incident where everybody tries to blame everybody else. Next will come the small matter of deciding who pays for all the expense. Hopefully, there will time for proper "wargaming" of the systems before too long, something that would have strengthened the response had it happened before, but may have been omitted because there had been no previous problems. I'm sure there will be chance one night for a simulation to develop a process for a quick recovery should it happen again.

[Electric train]

Seems my option that Heathrow Airport should have been able to supply the Airport from the other 2 GSP as widely reported in the media is backed up by the boss of National Grid
https://www.bbc.co.uk/news/articles/cdjy4m0n1exo

There is no doubt a war of damage limitation of the 2 public listed companies going on to protect from reputational damage, political focus, not to mention the clams for costs from Airlines.

As I said in my original post on Friday, I am surprised the Heathrow were not able to reconfigure the supplies, something they should have been able to do that night, the only thing that then my have effected flights was the smoke from the fire.

One company that is keeping its head well below desk level is UKPN. They manage the distribution network at Heathrow, as an independent DNO^▸ (Distribution Network Operator) (or the equivalent). But they have put out some quite hubristic stuff about this role in the past, e.g. this:

Security and reliability of electricity is essential for all airports. Heathrow is no exception. Even an interruption of a few seconds could have a knock-on effect on baggage systems and cargo shipments. This could take many hours to resolve and lead to significant lost revenue and passenger disruption. Resilient power is also vital to the entire airport community: including passenger transport services, employees’ facilities, freight and cargo operators, passenger retail or restaurants, emergency services, rail links, and airlines themselves. 

Providing 24/7/365 resilient power to a global transport hub requires continuous innovation and dedication. This means around-the-clock maintenance, repairs, and renewals to thousands of high voltage electrical substations, transformers, relays, and more than 600km of cables...

Approach and innovation

As strategic energy infrastructure partner, our approach has been to work with Heathrow to deliver world-class performance every single day. The faultless maintenance of critical energy infrastructure of this scale and density is vitally important: the risks to people, property and businesses from electricity cannot be understated if not managed correctly.

... and a world class excuse generator?

I agree about the excuse generator 

However it is still down to Heathrow Airport to have processes in place 24 / 7 to manage business interruption.  A major failure of a GSP is certainly something that is under constant consideration in the Southern Region of Network Rail

[Chris from Nailsea]

An update, from the BBC^» (British Broadcasting Corporation - home page):

Heathrow shutdown cause still unknown, report says

The root cause of a fire which led to the shutdown of Heathrow Airport and affected hundreds of thousands of journeys worldwide "remains unknown", an interim report says.

Heathrow was closed to all flights for much of 21 March after a fire at a nearby electrical substation, which started the previous night, caused a power outage at the airport.

In Thursday's report, the National Energy System Operator (Neso) said a transformer disconnected and caught fire at the substation in Hayes, west London.

The grid operator's final report is due by the end of June. Heathrow Airport said it welcomed the interim findings and that it hoped the final report would provide answers on what caused the fire.

The Metropolitan Police's counter-terrorism unit carried out an initial investigation into the fire, but Neso noted that detectives found there "no evidence to suggest" the incident was suspicious.

The power outage and subsequent closure of Heathrow led to more than 270,000 journeys being affected.

Energy Secretary Ed Miliband shortly after ordered an urgent investigation into the fire to prevent it "from ever happening again", and told Neso to provide its initial findings within six weeks.

Heathrow's management has been criticised for the decision to close the airport and the long shutdown that followed. Neso said power was restored to Heathrow's terminals seven hours before flights resumed.

In a detailed timeline, it said the fire at the North Hyde substation, which was built in the 1960s, started at 23:21 GMT on 20 March and resulted in a "simultaneous loss of connection". The power outage affected 66,919 domestic and commercial customers, including Heathrow Airport, Neso said.

A major incident was declared by the Met Police at 00:42, and Heathrow took the decision to close the airport at 01:11 the following morning.

Neso's chief executive Fintan Slye said: "It is important that the right lessons are learnt from this incident to prevent future instances where possible and to manage them effectively when they do occur."



Power was restored to Heathrow's substations by 06:25 using circuits from another nearby substation, Neso said, and the flow of electricity to all four of Heathrow's passenger terminals was restarted by 10:56. But Flights did not resume until after 18:00 that day, once safety checks were completed. Planes were able to land and take off through the night to allow Heathrow to get back up to full capacity.

Neso said the re-energisation of the entire airport was only fully completed by 14:23. Other customers' power was restored by 12:24, the report said, and supply from the North Hyde substation was reinstated the following day.

Heathrow relies on three electricity substations, and has emergency back-up power supplies, such as diesel generators and batteries - but these only keep crucial safety systems running, such as landing equipment and runway lights.

Heathrow's chief executive Thomas Woldbye previously said the shutdown was caused not by a lack of power but by the time it took to switch from the damaged substation's supply to the other operational substations. Due to Heathrow's "size and operational complexity", managers decided to close the airport on safety grounds while this took place. The airport said at the time that its objective "was to reopen as soon as safely and practically possible after the fire".

Neso confirmed that the restoration of power to the airport was followed by "a period of safety checking" to ensure "safety critical systems were fully operational prior to passengers arriving at the airport".

Heathrow said in a statement: "Further clarity on how the fire started and why two transformers were subsequently impacted can help ensure greater resilience for the UK^▸ (United Kingdom)'s energy grid moving forward."



Both the National Grid, which owns the North Hyde substation, and energy firm SSEN^» (Scottish and Southern Electricity Networks - website), which is responsible for power distribution in the area, said they welcomed the interim findings and would await Neso's full report.

London Fire Brigade (LFB), which sent 70 firefighters, previously said that the substation blaze "involved a transformer containing insulating oil which was fully alight". "This created a significant hazard due to being within a substation containing high-voltage equipment and the challenges of an oil-fuelled fire," it said in a statement. LFB explained crews had to wait for the transformer to cool down "before cutting through the steel casing to reach and extinguish pockets of fire that were inaccessible".

Following the publication of the interim report, Miliband said: "We now await the full report to understand what happened and learn lessons to strengthen UK energy resilience and protect our critical national infrastructure."