UK Grid to Report to Ofgem August 16

Following the widespread UK power cuts of August 9, National Grid is to submit an interim report to regulator Ofgem August 16, and a further technical report September 6, it told NGW August 13. It said that the former would not be for publication and it could not comment on the contents. Separately it is reporting to the government's Energy Emergencies Executive Committee, under Andrea Leadsom.

As a consequence of the short-lived cuts – all supplies were back within the hour and there was no discernible impact on prices, according to Cornwall Insight – an automatic shut-down took place in order to limit the damage. Transport was badly hit, with knock-on consequences including commuters being trapped on stationary trains for hours during the rush-hour.

National Grid's CEO John Pettigrew reportedly said on his LinkedIn page that one of the areas that would be examined in the aftermath was whether the disconnections might be prioritised differently in future. 

There has been speculation that it was the amount of renewables on the network that lowered the frequency below the statutory minimum and caused the failure: conventional power generation, with heavy turbines, provides the inertia the grid needs. Pettigrew said he did not believe there was a link but that the probes would examine the possibility. His post also said that other entities, including Network Rail, train operators and local grid operators, should also examine their own systems to see how they performed that day.

Nigel Cornwall, of Cornwall Insight, said that the demarcations between NG as Electricity Supply Operator (ESO) and the local distribution networks and how they are governed are likely to be considered. "Basically these arrangements have been in place for years and pre-date the increasingly decentralised system and they need revisiting," he said in LinkedIn.

The loss of power from the two stations, 1.48 GW, was greater than the largest loss of supply planned for: 1.32 GW, according to ESO.