The energy watchdog, Ofgem, is demanding answers from the National Grid after a major power cut caused travel chaos and cut electricity to almost 1 million people in England and Wales.
More than 900,000 customers have had their power restored after experiencing blackouts late on Friday afternoon after what the National Grid electricity system operator said were issues with two generators.
The power cut stopped traffic lights from working, plunged Newcastle airport into darkness, affected Ipswich hospital and caused major disruption on the railways during the busy Friday evening commute.
Ofgem said on Friday night: “In any incident the priority is to get power restored to customers as quickly as possible. National Grid has now informed Ofgem that the system has been restored.
“However, Ofgem understands the frustration this power cut has caused consumers. Ofgem has asked for an urgent detailed report from National Grid so we can understand what went wrong and decide what further steps need to be taken. This could include enforcement action.”
A back-up generator at Ipswich hospital failed after the power cut, a hospital spokeswoman said.
“There were some issues with regard to our outpatient areas and the generator that provides cover [to them],” the spokeswoman for East Suffolk and North Essex NHS foundation trust said.
Other generators worked as required and “patients were kept safe and cared for throughout” the 15-minute period before power was restored.
Prof Tim Green, the co-director of Energy Futures Laboratory at Imperial College London said he believed the two generators that disconnected were at Little Barford, in Bedfordshire, and Hornsea wind farm, in the North Sea off the coast from Hull.
“The first generator to disconnect was a gas-fired plant at Little Barford at 4.58pm. Two minutes later Hornsea offshore wind farm seems to have disconnected,” he said. “This might be linked to disturbance caused by first generator failing; might not.
“We will need to wait for National Grid’s full technical investigation to get to bottom of that.”
Around 300,000 UK Power Networks customers were affected in London and the south-east, a spokeswoman said, and Western Power Distribution said around 500,000 people were affected in the Midlands, south-west and Wales, with power restored to them all shortly after 6pm.
A spokeswoman for Northern Powergrid, which serves Yorkshire and the north-east, said 110,000 customers lost power, while at least 26,000 people were without power in the north-west, Electricity North West said.
Trains began to run out of King’s Cross late on Friday night after the station was shut down during rush hour.
The first train bound for Peterborough left the central London station at around 9.30pm after all services were halted for several hours. Passengers were filmed forcing their way through the barriers to try to board the first northbound service.
London North Eastern Railway tweeted on Friday evening: “Services heading towards London are now able to depart, however due to congestion across the network it will take some time to clear the backlog.”
Thameslink said its services would not be running north out of London for the rest of the day.
On Friday evening, a Network Rail spokeswoman said a power surge on the National Grid meant power was lost to all signalling over a wide area, including Newport, Gloucester, Ashford, Bristol, Eastbourne, Hastings, Three Bridges and Exeter.
“All trains were stopped while our back-up signalling system started up,” she sad.