An initial report into the cause of the enormous power cut that stranded commuters and inconvenienced the tea-making arrangements of home workers on August 8 has been released, with National Grid trying to ease blame away from itself and get a rogue lightning strike in trouble instead.
The NG's initial report [PDF] is fairly vague in its summaries, starting with an evocative scene-setting explanation of the day's events and mood, and says: "Prior to 4:52pm on Friday 09 August Great Britain's electricity system was operating as normal. There was some heavy rain and lightning, it was windy and warm – it was not unusual weather for this time of year."
It was a dark and stormy night, is what whoever wrote that really wanted to say, even though it was actually a normal afternoon. The afternoon's peace was about to be torn asunder by a lightning strike, the story then tells us, which tripped the safety on one transmission circuit; a circuit that returned to a perfect functioning state seconds later, as it is designed to do. The Grid added: "...this is normal and expected for a lightning strike on a transmission line."
But. However. Within seconds of this lightning strike and totally normal automatic reset Little Barford gas power station and the Hornsea off-shore wind farm both dropped out of the grid supply, triggering a harsh power frequency drop that set off safety processes galore, and caused the power cut across the south east; leaving 1.1 million customers without electricity. How these events are related isn't really explained, though, as National Grid only suggests that the power station outages were "...associated with the lightning strike" somehow, even though all of the protection systems appeared to work normally post strike.
Basically it doesn't know what happened yet, although regulator Ofgem would like a better answer than that -- and has launched a full investigation with the menace of massive fines attached. [Ofgem via BBC]