The National Energy System Operator (Neso) has issued its second electricity warning this week due to the ongoing heatwave, calling for an additional 700 megawatts (MW) of power generation to cover an expected shortfall between 7pm and 10pm on Friday.
Second Warning This Week
Neso, which operates Britain’s electricity network, issued the electricity margin notice after forecasting tight margins for Friday evening. This follows a similar warning earlier this week, which was cancelled shortly after 2pm on Wednesday when the grid operator became confident in supply levels.
The warning comes as the UK experiences sweltering temperatures, with rare red weather warnings continuing into Friday. The Met Office reported that temperatures reached 36.7°C in Merryfield, Somerset, on Thursday, provisionally making it the hottest June day on record in the UK.
Impact of Extreme Heat
A spokesman for Neso said the notice was “a routine tool” and “does not mean electricity supply is at risk.” However, extreme heat puts pressure on the electricity system by reducing the efficiency of power plants—including nuclear, gas, and water cooling systems—and increasing demand for fans and air conditioning.
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 demand, more than five times the daily average.
Previous Warning Cancelled
The earlier warning on Wednesday was cancelled after Neso determined that power supply levels were sufficient for the evening. The grid operator continues to monitor the situation closely as the heatwave persists.
