The body that operates Britain's electricity network has issued another industry call for additional power generation as the week's heatwave continues. The National Energy System Operator (Neso) warned that electricity supplies could be stretched on Friday evening.
Electricity Margin Notice Issued
Neso, responsible for balancing electricity supply and demand, issued an electricity margin notice for the period between 7pm and 10pm on Friday. The notice requests 700 megawatts (MW) of power generation as a buffer to cover an expected shortfall in electricity margins. This marks the second such call this week, following a similar notice issued before Wednesday.
However, the grid operator cancelled the earlier warning shortly after 2pm on Wednesday, indicating confidence in power supply levels for that evening. The new notice reflects ongoing concerns driven by extreme temperatures.
Record Heat and System Strain
Britain continues to experience sweltering conditions, with rare red weather warnings in effect through Friday. The Met Office reported that temperatures reached 36.7°C in Merryfield, Somerset, on Thursday, provisionally making it the UK's hottest June day on record.
A Neso spokesman explained that forecasts showed “tight margins on the electricity system” for Friday evening. “This is due to the impact of extremely high temperatures affecting Great Britain and the continent,” he said. The spokesman emphasised that the notice is “a routine tool” and “does not mean electricity supply is at risk.”
Extreme heat can pressure the electricity system by reducing efficiency and imposing operating restrictions on power plants, including nuclear, gas, and water cooling systems. Additionally, higher electricity usage for fans and air conditioning to keep cool further strains the grid.
Costs and Market Impact
According to analysis by Kraken, an AI grid platform spun out of Octopus Energy, Neso paid approximately £11 million on Tuesday to ensure the amount of gas entering the grid matched consumer withdrawals. This amount was more than five times the daily average, highlighting the financial impact of the heatwave on energy markets.
