Whistleblowers at the National Energy Systems Operator, which maintains Britain’s electricity supply, said the UK came close to a nationwide power shutdown last month.
They claim the grid fell outside safe operating limits.
The crisis, caused by one of the UK’s numerous heatwaves, was said to be hidden by senior officials in charge of the electricity grid.
A crisis occurs when the grid falls outside safe operating limits and has to use all possible supplies of power to meet demand.
This means that if any of these supplies had failed it would have triggered an automatic system shutdown causing power cuts across the country.
The staff claimed that members of Neso’s corporate affairs team were in the control room at the time of the crisis and were inappropriately involved in operational decisions.
They said that when the grid falls outside its safe operating limit, controllers cut off electricity supplies to some industrial users to rebalance supply and prevent a potential automatic shutdown.
In this particular incident, no customers were disconnected.
Neso is investigating, but insisted the system remained stable.
The last major blackout the UK suffered was back in 2019 when the Little Barford gas-fired power station in Bedfordshire and the Hornsea windfarm in the North Sea failed at the same time.
This caused large parts of the grid to automatically shut down.
The fear is that the UK could suffer a similar incident which afflicted Spain and Portugal last summer. The massive outage left 60 million people in both countries without power for over ten hours.
The blackout was triggered by overvoltage as the grid struggled to absorb sudden power losses, according to a European network report.
Red Eléctrica linked the fluctuations to sudden changes in renewable energy generation and slow response times from facilities controlling dynamic voltage.
Although renewables got the blame at the time, a later technical analysis revealed that conventional power plants, including coal, gas, nuclear and hydro, failed to adequately control voltage oscillations.
Spain’s regulations back then prevented renewable sources from providing voltage control services despite being technically capable.
