Britain’s electricity system frequency moved outside its normal operating range during June’s extreme heat but remained within statutory safety limits, NESO has said.
The National Energy System Operator said sustained high temperatures during the week beginning 22 June placed pressure on power systems across Britain and Europe. The Met Office had issued a red weather warning covering risks to life, travel and energy supplies.
Low wind generation, reduced gas power availability, high electricity demand, adverse interconnector flows and network constraints combined to create tight operating margins.
Craig Dyke, Director of System Operations at NESO, said: “Despite this, no customer demand was disconnected, frequency remained within statutory limits, the voltage stayed within limits and no lines or cables were overloaded.”
Grid frequency must remain close to 50Hz because significant deviations can damage equipment and threaten security of supply.
NESO uses a normal operating range of 49.8Hz to 50.2Hz during routine conditions.
The system moved outside that range at points between Monday 22 June and Friday 26 June.
Mr Dyke added: “At times, frequency moved outside the normal operating range. The lowest recorded value was 49.66Hz and the highest was 50.23Hz. Even at its lowest point, frequency stayed above the statutory lower limit of 49.5Hz and well above the level at which customer disconnections could occur (48.8Hz).”
NESO said it is analysing system and market performance during the heatwave as it does after all major events. The findings will be shared with industry through its Operational Transparency Forum and other channels.
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