Grimsby-based windfarm operator Orsted to pay £4.5m after huge UK power cut that left a million without electricity 

Offshore wind giant Orsted will pay £4.5 million into energy regulator Ofgem’s redress fund over the huge power cuts that left more than a million customers without electricity.

The company’s Grimsby-based Hornsea One wind farm, together with an RWE gas-fired power station at Little Barford, Cambridgeshire, did not stay connected following a lightning strike on an overhead transmission line on August 9 last year.

Both will contribute to the watchdog’s compensation package.

Ofgem’s investigation found that the combined loss of the two large generators and the smaller loss of generation at a local level, together triggered the disconnection, loss of power and disruption to more than a million customers.

This included many commuters and rail passengers in other parts of the country with traffic lights down and trains coming to a standstill, along with two airports and four hospitals.

Operators Orsted and RWE have agreed to make voluntary payments of £4.5 million each to the fund.

The regulator also said that UK Power Networks had started reconnecting customers without being asked to by the National Grid Electricity System Operator (ESO) which could have potentially jeopardised recovery of the system.

Ofgem said that this had no impact on the events but UK Power Networks had recognised this technical breach, taken swift action to prevent any future re-occurrence and agreed to pay £1.5 million into its voluntary redress fund.

Jonathan Brearley, executive director, said: “Consumers and businesses rely on generators and network companies to provide a secure and stable power supply.

“August 9 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 future-proof the networks to ensure consumers continue to benefit from one of the most reliable electricity systems in the world.”

Hornsea One, set to officially become the world’s largest wind farm when fully commissioned in the coming months, is located off the Humber approaches and operated from Grimsby.

It, and the gas power station operated by RWE, both stopped generating shortly after a lightning strike to an overhead transmission line in Cambridgeshire.

At the same time, approximately 150MW of smaller generation, known as distributed generation, also went offline and stopped generating, it added.

National Grid ESO activated back-up power generators to make up some of the shortfall and distributed generation to balance the system but when there was not enough back-up power generation available, local network operators automatically disconnected some consumers from the grid in order to prevent further system-wide disruption.

All customers were reconnected within 45 minutes of the lightning strike, the regulator said.

A Hornsea One spokesperson said: “Together with every organisation involved with the UK electricity system, we work hard to provide a reliable, resilient service and take any interruption very seriously.

“The power outage on August 9 was caused by an extremely rare sequence of events, involving a number of parties, and the issue we experienced at Hornsea One was quickly resolved. However, in recognition of our role in the outage, we have offered to make a voluntary contribution to Ofgem’s redress fund.

“We have co-operated with Ofgem throughout their investigations and conducted a thorough internal review of the events in order to prevent a situation like this from happening again.

“We will continue to work hard to bring clean, carbon free electricity to millions of homes across the UK.