A simultaneous malfunction at a wind farm and gas facility caused a power cut in the UK earlier this month, according to a new report.
The unexplained outages followed moments after a lightning strike, the National Grid Electricity System Operator said.
Officials said the lightning strike hit a transmission circuit at 4.52pm on 9 August.
Such strikes are common and the national grid’s protection systems cleared the lightning under 0.1 seconds.
But moments after the strike the UK lost five per cent of its power.
Simultaneous outages, associated with the strike, occurred independently at Hornsea offshore wind farm and Little Barford gas power station.
“The total generation lost from these two transmission connected generators was 1,378mw,” the NGESO interim report said.
The scale of generation loss meant that the 1000mw level of “backup” power held under regulations was insufficient.