LONDON (Reuters) - Britain’s energy emergencies executive committee said on Friday more work was needed to understand why certain power assets failed during a blackout caused by a lightning strike in August.
The power outage cut off 1.1 million electricity customers on Aug. 9.
National Grid said last month that the lightning strike resulted in Orsted’s Hornsea offshore wind farm and RWE Generation’s Little Barford gas-fired power station going offline.
The committee said in an interim report commissioned by the government that investigations were continuing.
“Further work is required to understand the exact failure mechanisms and whether these can be mitigated,” it added.
As Britain’s generation mix now includes a lot more renewable energy generation and interconnection with Europe, the grid system needs to be more flexible.
New forms of generation can provide flexibility but more work needs to be done by both generators and the system operator to ensure a continual balance between security of supply, resilience and the generation mix, the committee said.
During the one-hour outage on the evening of Aug. 9, some essential services were disconnected from supply, such as a hospital and Newcastle Airport.
This was because when 1 gigawatt (GW) of supply went offline there was a large drop in the frequency of electricity running through the grid.
Back-up power and other tools were used but the size of the generation loss meant the frequency fell to a level at which some demand was disconnected to ensure the safety of the network in a measure known as load shedding.
“Further review is required to identify essential infrastructure that is currently connected to (the load shedding mechanism), understand why they have been included in the scheme and whether it is possible to modify the scheme to minimise impacts to essential services,” the report said.
Communication policies at the grid operator, transmission operators, power generators, market regulator and the government should also be reviewed, it added.
The committee will submit a final report to the government at the beginning of next month.
Separately, energy market regulator Ofgem is conducting its own investigation into the August blackout.
Reporting by Nina Chestney; Editing by Edmund Blair and Louise Heavens