The National Energy System Operator (Neso) has issued an electricity margin notice for Friday evening, warning of a potential shortfall in power supplies during the ongoing heatwave. The notice, effective between 7pm and 10pm, requests an additional 700 megawatts (MW) of power generation to act as a buffer against expected tight margins.
Second Appeal This Week
This is the second such appeal made by Neso this week, following a similar warning on Wednesday. The previous notice was cancelled shortly after 2pm on Wednesday after the operator became confident in supply levels. The repeated appeals come as Britain experiences sweltering temperatures, with rare red weather warnings continuing into Friday in some areas and an amber warning for extreme heat in Greater Manchester.
The Met Office reported that temperatures reached 36.7C in Merryfield, Somerset, on Thursday, provisionally making it the UK's hottest June day on record.
Impact of Extreme Heat
A Neso spokesman said forecasts show 'tight margins on the electricity system' for Friday evening, attributed to 'the impact of extremely high temperatures affecting Great Britain and the continent.' The spokesman emphasised that the notice is 'a routine tool' and 'does not mean electricity supply is at risk.'
Extreme heat pressures the electricity system by reducing efficiency and imposing operating restrictions on power plants, including nuclear, gas, and water cooling systems. Additionally, increased use of fans and air conditioning drives up demand.
Financial Implications
According to analysis by Kraken, an AI grid platform spun out of Octopus Energy, Neso paid approximately £11 million on Tuesday to ensure gas supply matched consumer demand—more than five times the daily average. This highlights the financial strain of managing the grid during extreme weather events.
