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A fire at an electricity substation in West London caused a power outage to Heathrow Airport forcing it to close, impacting thousands of travellers as well as residents in the surrounding area, and now resilience plans are under scrutiny.
London Fire Brigade said it had received over 200 calls about the fire that started close to midnight on 20 March. The fire involved 25,000 litres of cooling oil which was fully alight, creating a major hazard with live high voltage equipment.
By 0042 on 21 March, the Metropolitan Police declared a major incident. At its peak, the Brigade had 70 staff on site, with ten fire engines, two Bulk Foam Units and a High Volume Pump used at the scene of the fire at the North Hyde electricity substation in the London Borough of Hillingdon.
“Firefighters safely evacuated 29 people from neighbouring properties, and as a precaution, a 200-metre cordon was established. Working with MPS around 150 people were evacuated to a rest centre.”
National Grid, which provides the power and manages the electricity distribution network across the UK said it was working with the electricity provider for the area, SSEN, to reconnect affected domestic customers, restoring it to over 60,000 customers by 0600.
The huge disruption at Heathrow Airport dominated the airwaves throughout Friday and the National Grid said in the early afternoon that it was working with SSEN to: “reconfigure the network to restore all customers impacted, including the ability to resupply the parts of Heathrow airport that are connected to North Hyde.”
National Infrastructure Commission chair Sir John Armitt said the incident highlighted the need for resilience stress testing.
“We’ve been clear the UK needs national resilience standards for our transport, digital, energy and water infrastructure. These will give clarity to operators and users about what levels of service they should expect in the face of short and long term disruptions, and ensure regulators have a clear yardstick against which they can ensure sufficient investment in resilience is made, proportionate to the risk.”
Regional failure of the electricity network is identified as a risk in the London Risk Register, where it is graded as likelihood rating of two and impact rating of three on a five point scale. At a national level, the National Risk Register shows this risk at three and three on its scale with the narrative focused on failure due to extreme weather rather than an acute unpredicted risk from a fire as was the case here.
The London plan puts the UK Power Networks as the lead for the risk, with controls including a testing and maintenance regime and emergency plans for the UKPN.
The London Power Supply Disruption Plan is another control; the document has not been updated since 2018 despite a response to question by a London Assembly Member in 2022 indicating that: “The document is maintained and revised on a rolling three-year basis as is the case for all London Resilience Forum response frameworks.”
Reacting to the continued closure, local MP and Chair of the Transport Select Committee, Ruth Cadbury told the BBC that there are questions about Heathrow Airport’s resilience that need answering.
Expressing her concern that Heathrow Airport relied on a single substation, she added: “Here in west London, we do have an issue about the overall grid capacity challenge in the boroughs of Hounslow, Hillingdon and Ealing, because the data centres are huge users of electricity but I think it is a question for Heathrow Airport, about whether they had previously considered this resilience concern themselves.”
Rich Preston, BBC journalist and host of the Tech Main Stage at The Emergency Tech Show, reported on the fire and highlighted the importance of the electricity grid as part of the country’s Critical National Infrastructure (CNI). This is defined as “national assets that are essential for the functioning of society, such as those associated with energy supply, water supply, transportation, health and telecommunications.”
“Whether that was deliberate or not, we don’t yet know. But there are serious questions about why better resilience wasn’t in place to protect such a vital part of British infrastructure.”
The incident is ongoing with reports of the power supply being restored but the chaos and disruption are likely to continue well after Heathrow Airport opens its doors again. Questions about the cause of the fire continue and scrutiny of resilience arrangements will consider whether the airport and the electricity network – a Category 2 responder under the Civil Contingencies Act – has robust enough plans to deal with such a crisis in the future.
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