GB Regulator Concludes August Power Cut Probe

British energy regulator Ofgem has concluded its investigation into the August 9 power cut without imposing any fines. It has also resolved to accelerate its review of National Grid's operations as the electricity supply operator (NGESO), it said January 3.

A lightning strike caused widespread disruption to the grid and two power plants went offline: the Hornsea One, part-owned by Orsted; and RWE's Little Barford plant. But they did not remain connected after the lightning strike and the operators have made voluntary contributions of £4.5 ($5.9)mn each into a fund controlled by Ofgem.

The combined loss of two large generators, one gas and one wind, as well as the smaller loss of generation at a local level, together triggered the subsequent disconnection, loss of power and disruption to more than 1mn consumers, Ofgem said. 

This included many rail passengers. Ofgem has worked closely with the Office of Rail and Road which has today published its findings into rail companies’ roles in the disruption. 

Ofgem also found UK Power Networks began reconnecting customers without being asked to by the ESO, which could have potentially jeopardised recovery of the system. UK Power Networks has recognised this technical breach, taken swift action to prevent any future reoccurrence, and agreed to pay £1.5mn into Ofgem’s voluntary redress fund, making £10mn in all. 

Ofgem’s investigation has raised questions about how the ESO’s management of the system is carried out. The incident has underlined the importance of ESO adapting to the complex and changing world it operates in, it said.

Ofgem said it would work closely with the government's Department for Business, Energy and Industrial Strategy ahead of its position paper on system governance in 2020.

Ofgem said: "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."