Britain could face an increased risk of power outages after the National Energy System Operator (NESO) announced plans to operate the electricity grid with lower levels of inertia.
Inertia helps stabilise the power system by keeping turbines and other rotating equipment moving when there is a sudden loss of electricity generation.
NESO said lowering the minimum inertia threshold would save consumers about £96 million annually, while insisting that the change would not result in a significant increase in the risk of blackouts.
The operator said it plans to use new assets and modify existing infrastructure to provide inertia as Britain transitions towards a low-carbon electricity system.
Traditional coal, gas and nuclear power stations naturally provide inertia through their heavy rotating turbines. However, wind and solar power systems generally do not provide the same type of inertia, prompting NESO to explore alternative methods of maintaining grid stability.
NESO said rapid-response batteries and other technologies would help the system respond to sudden changes in electricity supply.
Some energy companies have, however, raised concerns about the proposed changes.
Drax, operator of Britain’s largest power station, warned that the projected savings would be insignificant compared with the potential economic consequences of a major system failure.
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EDF, which operates Britain’s nuclear power stations, also urged caution, warning that a country-wide or regional blackout could result in losses far exceeding the expected savings.
“Maintaining grid stability is becoming more challenging as the system becomes more diverse,” an EDF spokesman said, adding that reducing minimum inertia levels during the current energy transition was premature.
The development has also prompted warnings from some NESO engineers, who claim that the electricity system is becoming increasingly difficult to manage as Britain expands its reliance on renewable energy.
The engineers said they had repeatedly raised concerns with NESO and the regulator, Ofgem, over the stability of the electricity network.
Their concerns intensified after leaked documents reportedly showed that the system came close to shutting down on June 23 following a shortage of wind and solar generation.
Ofgem subsequently ordered an investigation into the incident.
One whistleblower described the prospect of a future major blackout as an “engineering certainty”, while alleging that safety concerns had not been adequately addressed.
NESO, however, rejected the claims, insisting that the secure operation of Great Britain’s electricity system remained its highest priority.
“The analysis shows these proposals will maintain system security while delivering significant savings for consumers,” a NESO spokesman said.
The Department for Energy Security and Net Zero also defended the reliability of the UK electricity system, saying Britain had one of the most reliable electricity networks in the world.
It added that there had never been a complete shutdown of the national grid in its 75-year history and said the government remained confident in the country’s electricity security arrangements.