More than a million people were affected by the power cut on Friday 9 August 2019 following a lightning strike on the transmission network north of London at 4:52pm.

Households suffered electricity outages of between 15 and 50 minutes while commuters in London and the South-East faced severe travel chaos in the evening and into the next day as some trains couldn’t operate until an engineer attended. Both Ipswich hospital and Newcastle airport also lost power for a brief time.

Energy regulator Ofgem revealed that while lightning strikes are routinely managed so that power generation wouldn’t be expected to trip off or de-load, the loss at two large power stations and a smaller loss of generation at a local level triggered the outages and disruption.

A report into the event stated: “The two almost simultaneous unexpected power losses at Hornsea One Ltd offshore windfarm, co-owned by Orsted, and Little Barford gas power station, operated by RWE represent an extremely rare and unexpected event”.

Following the lightning strike, the power stations reduced their output “beyond the security standards resulting in a large and fast fall in frequency” which impacted 1.1 million people.

They have agreed to pay out £4.5m each and UK Power Networks will also pay £1.5m into Ofgem’s redress fund for a technical breach.

Ofgem found that local network operators disconnected and reconnected consumers in response to the loss of power as expected. But UK Power Networks began reconnecting customers without being asked, which could have potentially jeopardised recovery of the system.

All customers were reconnected by the Distribution Network Operators within 45 minutes of the lightning strike.

The investigation also found software flaws on some trains which extended the delays for commuters. Any commuters impacted by the power loss are able to apply to rail operators for compensation.

‘Futureproof the networks’

Jonathan Brearley, executive director of Ofgem, said: “Consumers and businesses rely on generators and network companies to provide a secure and stable power supply. August 9^th showed how much disruption and distress is caused to consumers across the UK when this does not happen. That is why it is right that companies that were unable to keep generating have paid into our consumer redress fund.

“Our investigation has raised important questions about National Grid’s Electricity System Operator, which is why our review will look at the structure and governance of the company.

“As the energy market changes it is vitally important we futureproof the networks to ensure consumers continue to benefit from one of the most reliable electricity systems in the world.”