Terms Set for NESO Review of the Heathrow Substation Fire and Closure

According to the terms of reference, power was quickly restored to affected customers and Heathrow restarted operations from late on 21 March, but there was significant disruption at the airport over the weekend of 22 and 23 March. The Energy Secretary and Ofgem have commissioned the National Energy System Operator (NESO) to review the incident under condition C7.5 of the Electricity System Operator Licence.

What the review will examine

NESO will report on three pillars:

• Resilience of energy infrastructure: the root cause, contributing factors and sequence of events at North Hyde, alongside the London Fire Brigade investigation; the direct and secondary impacts, including why the outage resulted in the closure of Heathrow; and where improvements are needed.
• Response and restoration: the contingency planning in place for failure of electricity infrastructure, whether plans worked as expected, and the timeliness of the response and communications.
• Resilience of critical infrastructure: recommendations for improving the resilience of essential services, including critical national infrastructure, to power disruption.

The London Fire Brigade investigation will also explore compliance with the Regulatory Reform (Fire Safety) Order 2005.

What the review will not cover

The terms of reference state that NESO will not investigate the knock-on impacts on transport resulting from the airport's closure, which will be covered by a separate review led by Ruth Kelly, and will not look more widely into airport operations or the impact on airport customers and the aviation industry.

Timetable and why it matters

NESO is to submit an initial report to the Secretary of State and Ofgem within six weeks and a final report, with recommendations and where possible an implementation plan, by the end of June 2025. For airlines, insurers, airport operators and other operators of critical sites, the findings and recommendations are likely to inform contractual risk allocation, business interruption claims and resilience planning.

Sources

• GOV.UK: NESO review into the North Hyde substation outage, terms of reference (28 March 2025)
• GOV.UK: Review into the North Hyde substation outage, terms of reference (publication page)