Heathrow Airport has announced it is operating at full capacity again after a significant power outage caused by a fire at an electrical substation significantly impacted operations, affecting over 200,000 passengers.

The electrical failure, which originated from a blaze in Hayes, west London, resulted in a suspension of flights for about a day, grounding more than 1,350 flights and leaving many passengers stranded at the airport and abroad.

In response to the incident, UK Energy Secretary Ed Miliband has tasked the National Energy System Operator (Neso) with conducting an urgent investigation.

This inquiry aims to understand the root causes of the power outage and to examine the broader resilience of energy systems serving critical national infrastructure.

Ofgem, the energy regulator, has pledged to take necessary actions if any breaches of standards or license obligations are uncovered during the investigation.

Miliband stated that the government is committed to preventing a recurrence of the incident that led to significant disruptions.

The fire itself has since been deemed non-suspicious, and the London Fire Brigade is now leading the investigation into the specifics of the electrical equipment failure.

Heathrow's Chief Executive, Thomas Woldbye, expressed his commitment to cooperating with all stakeholders to ensure a thorough analysis of the incident.

Woldbye acknowledged that operational challenges arose from a failure of backup transformers during the outage, necessitating a reorganization of power from remaining substations to restore electricity supply to the airport’s extensive infrastructure.

Reflecting on the impact of the closure, Heathrow reported a strong recovery, with a scheduled operation of over 1,300 flights on the following Sunday.

British Airways, who operates a major portion of the traffic through Heathrow, stated it expected to resume nearly all scheduled flights and advised passengers to arrive at the airport as planned, unless otherwise informed.

Heathrow’s chairman, Lord Paul Deighton, indicated that an internal review is being conducted to assess the airport's crisis management plans during the incident.

Former Transport Secretary Ruth Kelly, an independent board member of Heathrow, is overseeing this review.

Deighton asserted the need for a thorough evaluation of the airport's response to improve future resilience and operational readiness.

Transport Secretary Heidi Alexander remarked on the urgent need for lessons learned from this incident, emphasizing the significance of the airport in national transportation infrastructure and reassuring the public that measures must be taken to ensure robust operations in the future.

Despite the resumption of flights, temporary disruptions are anticipated as operations normalize, with passengers advised to check with airlines concerning flight statuses and potential further impacts.

Additionally, the incident has drawn increased scrutiny regarding the resilience of Heathrow's power supply, with calls from experts for evaluations of the infrastructure supporting such critical facilities to prevent similar occurrences.

The government and relevant agencies remain engaged in exploring ways to enhance energy security across the UK’s vital services.