Heathrow's power outage - a one-off?

Last Friday, one of the world's largest transport hubs came to a halt for 18 hours after a fire broke out at one of its substations in North Hyde.

Since the incident, National Grid's CEO responded to accusations that Heathrow bosses were forced to shut down the airport due to a lack of power, confirming that the two other substations were operational and fully capable of powering the airport.

Why, then, was the airport not able to connect the power, and why did it take so long to return to its operations?

In this week's episode, Richard speaks to Simon Gallagher, grid expert and MD of UK Network Services, a leading independent energy networks consultancy, about some of the wider concerns this outage raises about the country@s energy security. How vulnerable is some of its crucial infrastructure?

 Host: Richard Sverrisson - Editor-in-Chief, Montel News
 Guest: Simon Gallagher, Managing Director of UK Network Services

 Editor: Bled Maliqi
 Producer: Sarah Knowles

Transcript

Richard Sverrisson - Editor-in-Chief, Montel News: 0:02

This week listeners were diving into a story that shocked travelers, disrupted flights, and raised major questions about energy resilience at Europe's busiest airports. I'm talking about the fire, the electrical substation on the edge of Heathrow just outside London, which brought this international travel hub to a standstill exactly a week on from the fire itself I traveled through the airport myself. It's a busy morning at Heathrow Airport. I'm standing outside terminal two, and I can see the usual mix of tourist and business travelers, some rushing to their gates, others sing through the terminal without a care in the world, all heading to destinations all over the world. Completely unaware and maybe even unaware what happened a week ago. Last Friday, this airport, one of the busiest in the world, was forced to close its doors. For a full 24 hours after a fire knocked out a power substation at North Hyde. Flights from India to Istanbul, from Toronto to Tallin were affected. Many turned around or redirected. The airport was forced to close with thousands of passengers stranded. It city's largest transport hub came to a standstill, but today it's a return to normal. The flights are taking off, the terminals are busting with activity. Power is back, planes are in the air and taxiing across the runway. But this Air of Normality masks some various serious questions that Heathrow the UK TSO and the British government have failed to answer. How could a single fire at a substation knock out the entire airport? Why didn't Heathrow quickly reroute power from other substations? Why didn't the airport's power generators kick in and provide enough power to keep the airport going? Hello listeners and welcome to Plugged In the energy news podcast from Montel. Each week we bring you in-depth analysis and insights from across the energy sector. I'm Richard Sverrisson. I'm back here in our Oslo studio and thankfully, power was restored at Heathrow. Now helping me to answer key questions about the outage at Heathrow and much more is Simon Gallagher managing director at UK Network Services. Welcome to the podcast Simon.

Simon Gallagher, Managing Director of UK Network Services: 2:13

Thank you for having me.

Richard Sverrisson - Editor-in-Chief, Montel News: 2:15

So if we could start by just setting the scene a bit. Really, I think Heathrow how much power does it consume and where does that power come from?

Simon Gallagher, Managing Director of UK Network Services: 2:25

Heathrow has a peak demand of about 40 megawatts. And it's actually fed from three different, what we call grid supply points in the UK. So each and in theory, each one of those can actually supply Heathrow all by itself. So one of those grid supply points did have a fault, and we've seen it spectacularly on the news with the transformer fire, so we can get into what happened there. But effectively, one of the grid supply points failed and then Heathrow shutdown operations.

Richard Sverrisson - Editor-in-Chief, Montel News: 2:55

Sure. We'll get to the details about that in a second, Simon. But what, in terms of backup, what does Heathrow have in terms of backup? Does it have own site generation as well?

Simon Gallagher, Managing Director of UK Network Services: 3:04

Well, they have these three independent supplies in theory, which in itself is a level of resilience. But it appears now, I don't know the ins and outs. Inside the airport, but it appears you have backup for their critical safety systems. So they have backup for the runway lights, air traffic, control, radio systems the landing system. So safety was never compromised because all that things stayed up. But there's two important points that the first is that with these safety critical systems, once you go onto your backups. You then have no further backup. So actually same. You can't use them. They're there for emergencies. And the wider airport did not have generation backup. So while in theory their safety critical systems were running, nothing else was operating so the terminals were shut, the baggage handling systems were shut, and that's ultimately what forced them to shut down.

Richard Sverrisson - Editor-in-Chief, Montel News: 3:58

So if we can go back to what actually happened. So there was a fire at a substation, a north hide substation early in the hours on Friday, was it Friday the 20th of March?

Simon Gallagher, Managing Director of UK Network Services: 4:07

Yeah, I think it actually started at around 11 o'clock the night before where that substation called North Hide. It's fed from another substation called Iver in West London. So it's got two 275,000 volt circuits run to North Hide. And in North Hide, there's three transformers there. 2, 7, 5 to 66. The one of the transformers went on fire at field. So I mean, field transformers is a thing that happens generally. They trip out fast and they don't spectacularly feel, but in this case, unfortunately, one of the transformers failed. It went on fire, and of course there's 20,000 liters of oil within this transformer. It went on fire, which was actually in, it's a, it's environmentally it's terrible, but from an electricity point of view, the national grid can cope with that. With one transformer field, the grid actually carried on fine at supplies, but unfortunately right next to that transformer that went on fire is a second transformer. That got damaged in the heat it's too close to be able to maintain supply. So the second transformer also failed because it got damaged in the fire, and that was the stage then where National Grid could not then maintain supply. So there's about 60,000 customers connected to that substation. They all lost supply at that point, including Heathrow Airport.

Richard Sverrisson - Editor-in-Chief, Montel News: 5:34

But there's nothing suspicious about the fire. It was just something that's one of these things that, unfortunately does occur now and again.

Simon Gallagher, Managing Director of UK Network Services: 5:39

There's nothing. You'll have seen the news reports originally. Was all, is this sabotage or is there a state actor involved? No it looks like a, it just looks like a, an equipment failure.

Richard Sverrisson - Editor-in-Chief, Montel News: 5:49

But you said that the 60,000 people were cut off, but they, the power was restored fairly quickly.

Simon Gallagher, Managing Director of UK Network Services: 5:55

Yeah, so the distribution network operator in the area, Scottish and Southern electricity Network. So they then started rearranging their high voltage networks to use supplies from other. Places, so SSEN were able to reconfigure their network to get supplies back on. But the bit of Heathrow that was off, that was a 20 megawatt. Chunk. That's quite a big bit to try and pick up on the network when you've lost one of your grid supply points.

Richard Sverrisson - Editor-in-Chief, Montel News: 6:22

So what I mean, so there was enough power to supply, those 60,000 in Scots, in Southern managed to restore the supply there. What why was that not the case for Heathrow?'cause as you said, 20 megawatts is obviously much higher than 60,000 customers. Their consumption.

Simon Gallagher, Managing Director of UK Network Services: 6:39

Yeah. So at SSEN we're able to split their network up and reconfigure things. So now we don't know. Ultimately it took them all day to restore all the customer supplies in the area. So what we don't know at this stage is did they manage to restore it without hide coming back on? Or did they restore bits of hide? We don't know. But with Heathrow. Yes, it's a big chunk to try and pick up elsewhere, but the real question for Heathrow is you have a high voltage network on site that's connected to these three different supply points. Why is it when one field you weren't able to reconfigure things? But I do have sympathy here in that it does take time to reconfigure high voltage networks. And there. We don't really know what the design of that network is. So there may be design limitations, there may be hardware limitations. We don't quite know, but I think it's a fair question to ask. Why could that network not be reconfigured relatively quickly to take supply from these other places?

Richard Sverrisson - Editor-in-Chief, Montel News: 7:38

This is one of Europe's biggest transport hubs, if not the biggest. And it's quite a small outage affecting true tube transformers, if I understood you correctly there, Simon. But it, it raises some serious concerns about the UK's energy security and the resilience of the network. I mean, how would you gauge the significance of what happened on Friday?

Simon Gallagher, Managing Director of UK Network Services: 7:58

It's massively significant because of the effect, the take through one was the world's largest. Airports, but if this had not have affected Heathrow, it would be a regional news story. 60,000 customers is a tragedy for the people who are involved. Of course. But 60,000 customers is not a huge amount of people to lose supply. In the grand scheme of things, we lose far more in storms. But of course, Heathrow is protected which raises two big questions. It raises the question I mentioned about why couldn't Heathrow reconfigure themselves? Because in theory they have a secure supply because they've got these three independent in feeds. But also, why does Heathrow not have a lot of generation backup? So if we compare Heathrow to some other industries, and not just Heathrow by the way, but all airports in the uk. So right next to Heathrow, in fact, within 20 meters of the fence of the substation where the fire happened, there's a brand new data center and that data center will ultimately consume 150 megawatts. So three, four times what Heathrow consumes. Now the first data hall has opened on that data center, and that's about 30. Megawatts and that's connected via 66,000 volt cables to North High, the exact same substation. But the big difference in that data center and Heathrow is the data center has got 100% generation backup. So they've actually got 12 Rolls-Royce large generators, a couple, I think they're three megawatts each. So in the event of a fault, and this did happen, the FT reported this, that the data center seen the same loss of supply, but their backup systems kicked in instantly. Their generators fired up, they never lost operations. Even to the extent that they've got 12 generators, but they only actually need 11. One of them is there to back up the backups. So it's a fair question to ask. If a data center can protect itself so well, you cannot say this data center. Was more important than Heathrow. So there's definitely broader questions around how is resilience handled by the airport industry.

Richard Sverrisson - Editor-in-Chief, Montel News: 10:05

Absolutely. I think, Heathrow is a household name, whereas this data center is probably known by very few maybe the technical data nerd Simon. But but how come they were provide able to provide this backup? But Heathrow wasn't, I think, and you talking 11, 12 backup generators I presume they're gas fired or diesel.

Simon Gallagher, Managing Director of UK Network Services: 10:25

Diesel diesel.

Richard Sverrisson - Editor-in-Chief, Montel News: 10:25

Yeah. Yeah. Does that raise questions that about Heathrow and other maybe UK airports that they. Should put in place measures to provide that kind of backup? What? What are your views here?

Simon Gallagher, Managing Director of UK Network Services: 10:36

Yeah, I think it does, like most airports in the UK don't even have this level of resilience that Heathrow does. So Heathrow's got these three GSPs. Most other airports don't have that. I think what's happened is the airports are more mature industry, so things have changed over time. So they're probably, the airports are probably more critical to business and daily life than was 20 years ago. Whereas the data centers that are a new young industry, I think they're more attuned right now to what is the impact that they lose their operations, which is catastrophic for their business models, but also catastrophic for their customers in terms of they would feel as well. So the data center seems to have done. We cost benefit analysis that it's worth spending million and it is millions of pounds on generators. It's worth spending this millions of pounds to guard against an exceptionally rare event, which is what this power loss is. They've made the business case that it's worth doing that, whereas I don't think the airports have actively not done that. It's just that things have changed over time and now that needs relooked at again.

Richard Sverrisson - Editor-in-Chief, Montel News: 11:42

There's legacy industry versus quite a modern UpToDate there, there's those two ways of looking at it. Would that be fair Simon?

Simon Gallagher, Managing Director of UK Network Services: 11:49

I think that's exactly what's happened. We've got a legacy, mature industry with a different take now on what's a more a younger industry.

Richard Sverrisson - Editor-in-Chief, Montel News: 11:58

And I think do, you would expect then to to see such backup solutions being introduced. Not just a Heathrow brother, other airports, if you are talking, they need ant. They need to be diesel generators, but they could also be bat battery backups, couldn't they? That would be perfectly possible in these kind of scenarios, would they not?

Simon Gallagher, Managing Director of UK Network Services: 12:15

You have to have both really. So those data centers have got UPSs because, the generators take a few minutes to spin up. So you have to bridge that gap. UPS some what could you explain that to on interruptible I struggled. Okay. On Instructural power supply. So basically, yeah, the data center's fed via batteries so that if the grid fields, the batteries can maintain the full supply for a few minutes while the generators kick in.

Richard Sverrisson - Editor-in-Chief, Montel News: 12:40

Gotcha. Gotcha. But I think, with data centers you mentioned, it's catastrophic if they go down. Heaven forbid, we have to, chatGPT goes down or you stop mining Bitcoin. But of course they have other much more important ways of, or other customers. But if, but it, but losing or disruption to, what was it 250,000 passengers that's also quite catastrophic. It's certainly an embarrassment. And if not catastrophic for Heathrow.

Simon Gallagher, Managing Director of UK Network Services: 13:07

Undoubtedly. But I think if, there's two schools of thought here in that if you look at a data set, so their critical loads are actually, they are serious. So it's like financial institutions. It could be trades worth billions of pounds slow between the London Stock Exchange and New York Stock Exchange. So that, yep. That's the kind of things that. Presumably their collateral exposure is huge. If any of that fail with the data center, they probably have huge contractual penalties if they feel like, business ending type costs. But there's an argument that says, yeah, the airports, so if Heathrow fails, a lot of the financial costs is actually externalized. With the Heathrow failures, probably the airlines who are bearing the brunt of the financial penalties rather than Heathrow. So there, there might be a slightly different incentive for the data centers over Heathrow, but regardless of the actual point note cost, at the end of the day, I think the airports will have to be more resilient after what's happened.

Richard Sverrisson - Editor-in-Chief, Montel News: 14:05

Yep. And I think you, you have the airlines and certainly the representatives of the airlines or the association airlines were the most critical in their voices on that Friday and the subsequent days, weren't they? But is there a vulnerability here at airports that. That could be the case elsewhere in Europe as well, not just in the United Kingdom.

Simon Gallagher, Managing Director of UK Network Services: 14:23

Yeah, the UK is not special in this regard. So Skip all had problems back in 2018 where they actually seen high voltage fluctuations on their high voltage, power supplies and they actually went off as well. So Skip had these big problems. They didn't have enough generation to back up their terminals either. But since that, they have put in more generation now and they actually tested quite regularly. So they will actually switch their terminals off from the main supply while they're in operation. So not just a theory thing, they will actually turn their terminals off to test their backup systems while the airport's open during the day. And then if we look internationally. Dubai, for example. Because this is what Heathrow needs to be compared to. Really, it's big international hub airports, so Dubai International, they've actually got three independent grid supply point feeds as well. And then they have extensive onsite generation, more akin to the data centers in the UK.

Richard Sverrisson - Editor-in-Chief, Montel News: 15:20

Absolutely. And I think also in the aftermath of the incident, you heard from the CEO of the National Grid saying that there was power, was a, was available even if the airport was not tapping into what's your, what are your thoughts here, Simon?

Simon Gallagher, Managing Director of UK Network Services: 15:32

That goes back to that point that and it is right, that they did. So they've got these three different independent supplies from three different substations, three different grid supply points, and the point that. CEO of National Grid is making. Yeah, we had a, we definitely had a problem. We lost one of our supplies to you, but you had two still live, which had the capacity to feed your airport. So why did it take you 18 hours to get yourself back online? And this goes to this question about why did it take so long to reconfigure your 11,000 volt network on site? And there may be multiple answers for that. Like I said at the start, it may not be configured to do that. There may be design limitations we don't know at this stage.

Richard Sverrisson - Editor-in-Chief, Montel News: 16:15

And now there's a probe or an investigation into the issue. So we probably have to wait to six weeks or more to find out what, what actually happened. But is there a wider, concern about the vulnerability of the UK's energy infrastructure here. Does it raise just, not just the airports or data centers, but maybe, more and more capacity is coming online and both in forms of, the kind of generators you mentioned, batteries and also production sites with offshore wind or onshore wind, onshore solar, what does this say about the grid in the UK? Is it at straining point?

Simon Gallagher, Managing Director of UK Network Services: 16:48

I think we need to be careful when we look into a rare one off, we call these high impact, low probability events when these happen and every few years there's one of the, so in my own career in the company I used to work for, we lost 4 1 3 2 KV oil fill cables over a cable bridge in South London, and that took out South London for a while. So there's multiple of these things happen, but. What it ex, what it shows to me is that they are very rare events and they do usually expose some unknown thing. But if you take a step back and look at the UK as a whole, we have got some of the most reliable ultrasound networks on the planet. So if you look at the UK's average. I teach per person. In the UK it's very low. If you look at the UK's average duration of fault per person in the uk, it's very low. When I started, 20 years ago, we used to have an average, every person in the UK had no power for about a hundred minutes on average, 120 minutes. Now in London, it's less than 30. So the UK is actually very reliable, but when you have an issue that affects a big customer, a big important thing like Heathrow, of course, that then needs a very close look.

Richard Sverrisson - Editor-in-Chief, Montel News: 18:00

Yeah, absolutely. I think that's the crew is, it's important to remind ourselves that this is a very rare event. Yeah. But of course it is quite dramatic when it affects an international airport of the size and reputation of Heathrow. But we mentioned in the introduction a little bit Simon, when we just started chatting before we started recording about state actors or involvement of state actors here, and there was a suspicion there, but that's obviously not happened in this case. But if I were a malevolent state actor or wishing to disrupt the energy infrastructure, would I look at this and think, ah, I just need to get, put a attack attack these kind of trans. Performers or these substations 'cause they're vulnerable to these to, to that kind of attack.

Simon Gallagher, Managing Director of UK Network Services: 18:39

I think that the vulnerability of any country's power system is well known. So it's not a, anyone who would be thinking about attacking the UK's par system already knows that it could be attacked and where the weak points are just like every other country. And it wouldn't if you asked me to look at a third country and say, where's the weak points here? You need, all you need is Google Maps to have a look around. So yes, there's vulnerability. I won't say the UK has done quite a lot to guard itself against this, but. Probably not one to go into in a podcast, but there, there is a lot of security now to prevent a lot of these things happening.

Richard Sverrisson - Editor-in-Chief, Montel News: 19:15

Absolutely. And we see the, with certain interconnectors between cold countries, certainly in the Baltic countries, that sort, that's also the, highlighted some of the vulnerabilities here with some of the infrastructure. But you mentioned data centers and that, that's the data centers there close to Heathrow. Is this, what's the outlook for data centers in the uk and what impact could they have on the grid?

Simon Gallagher, Managing Director of UK Network Services: 19:35

We are seeing a huge demand for data centers now. So data centers a few years ago were 20, 30 megawatts was a big data center. The one that just connected next to Heathrow is 150 megawatts which is huge.

Richard Sverrisson - Editor-in-Chief, Montel News: 19:48

Yeah. Yeah.

Simon Gallagher, Managing Director of UK Network Services: 19:48

We're actually working on, one of the men is 300 megawatts, so you know, that's a UK city. And actually when we talk about the transmission system, national Grid's 400 kv and 2 7 5 kv and Scottish Power Scotland, then SSEN of Scotland, a direct. Connection to those networks for demand was actually unheard of until recently. Whereas now these data centers are connecting directly to the transformation network. So there is a huge demand for them right now. Yes.

Richard Sverrisson - Editor-in-Chief, Montel News: 20:19

And how does this relate to the issue of zonal versus national pricing as well? Because if you had, you mentioned this data center, close to it's on the outskirts of London, but surely if you have, if all the data centers were around London, that the grid would be put under an impossible strain. In Ireland, Dublin has forbidden more data centers around, around Dublin. Could that situation arise in, in the uk do you think? Simon,

Simon Gallagher, Managing Director of UK Network Services: 20:40

We are seeing that situation, slaw in West London has got the highest concentrated data centers in Europe. Mostly because it sits on the transatlantic fiber networks from the city of London to New York. So we're already seeing that in that the driver of data centers does seem to be. Heavily focused on London because you do have X industrial sites, like you've got the old power station sites that in theory have a huge big demand connection available, but, and I'm not a comms person, but for a communications point of view, they want to be around London. Now that is changing a bit. People tell me that with Edge AI, you don't need to be so close to London, but. Currently we do see a, definitely a favor of London for these data centers, which is why, the power problems in West London, the capacity constraints there are quite well known and publicized.

Richard Sverrisson - Editor-in-Chief, Montel News: 21:30

Yep. And I think that's one of the arguments for zonal pricing is to, to have lower prices, say in the north, in Scotland, where to attract these kind of this kind of infrastructure.

Simon Gallagher, Managing Director of UK Network Services: 21:40

Yeah. I am on. The jury's out with me on zonal pricing because I can totally understand why. Yeah. Let's use price signal to attract industry to those areas where we have the infrastructure and the capacity. But at the same time, if I own a factory that happened to be in a place worth now expensive, why is that fair? On me and the people who I employ. All of a sudden, I can't do anything about relocating my factory right now. So there's like all these things. There's winners and losers and we just need to be careful, which has got the biggest societal benefit.

Richard Sverrisson - Editor-in-Chief, Montel News: 22:10

Absolutely. The devil is always in the detail there. Simon. Thank you Simon, for a fascinating discussion. I think it it's clear it was quite an embarrassment to the UK government, but I think it's very good to get an overview of what actually happened and what led to that outage. So thank you for clarifying that Simon.

Simon Gallagher, Managing Director of UK Network Services: 22:27

No problem. Thank you for having me.

Richard Sverrisson - Editor-in-Chief, Montel News: 22:29

It's been an excellent and insightful discussion. I hope you agree, listeners, and thank you for tuning in to this episode. Our podcast episodes are released every Friday. For the latest news from Montel, please visit montelnews.com and you can follow us on LinkedIn, Bluesky and other social media channels. See you next time.