Heathrow paralysis: Substation fire exposes UK grid vulnerabilities

A fire at the North Hyde electricity substation near London’s Heathrow Airport led to a major power outage on March 20, causing the shutdown of Europe's busiest airport. The incident left thousands of passengers stranded, disrupting more than 1,300 flights, with 120 already in the air at the time. The fire severely impacted the airport and surrounding areas, cutting power to 67,000 homes and businesses overnight.

While authorities are still investigating the exact reasons for the widespread disruption, The Conversation publication has interviewed several experts who offered insights into several factors that may have contributed to the incident.

Barry Hayes, an associate professor in electrical power systems at University College Cork, explained that the fire involved a 275kV transformer, a crucial component of the local electricity grid. Normally, critical infrastructure like Heathrow should have multiple power supply points to prevent a single failure from causing such large-scale disruptions. Some reports indicated that parts of the airport, like Terminal 5, still had power, suggesting that redundancy mechanisms were in place but failed to work as expected.

One reason for the extensive impact could be the strained state of the UK power grid. The North Hyde substation serves a highly constrained area, with increasing demand from new housing developments, commercial investments, and data centers. The UK’s aging power infrastructure is another factor, as many components are at the end of their service life and require urgent modernization. These vulnerabilities may have played a role in the Heathrow shutdown.

Failures in backup power systems

Professor Kirk Chang of the University of East London highlighted another major issue: the failure of Heathrow’s backup power systems. While it is clear that the fire caused the outage, the backup generators should have immediately taken over. This raises two key questions: why did the backup systems fail, and who was responsible for managing the power response?

There are two possible technical reasons for the failure. The backup machines may not have had sufficient fuel, or the system might not have been properly linked to the grid. Typically, a primary backup system (Plan A) provides about 90% of the required power, while a secondary backup (Plan B) covers around 30-50%. The failure of both Plan A and Plan B is highly unusual and suggests a serious flaw in Heathrow’s power contingency planning.

Wider implications for energy sector

Hayley J. Fowler, a professor of climate change impacts, emphasized the broader significance of this event. The Heathrow shutdown highlights the critical importance of maintaining national energy infrastructure, especially as demand for electricity increases with the transition to low-carbon technologies like electric cars and heat pumps.

The UK’s energy system is also facing growing risks from extreme weather. While the exact cause of the Heathrow fire remains unknown, most energy system failures in the UK are linked to severe weather events such as storms, flooding, heatwaves, and cold spells. The year 2024 was the warmest on record, with climate change driving more frequent and intense extreme weather events.

Gas and electricity operators have invested in protecting critical assets, but recent storms, including Arwen and Éowyn, have exposed weaknesses in the system. These events left thousands without power for days, revealing that the UK is still underprepared for extreme weather threats.

By Nazrin Sadigova